McKenna's Drug Handbook for Nursing & Midwifery, 7e

Seventh Edition

McKENNA’S DRUG HANDBOOK FOR NURSING AND MIDWIFERY

Lisa McKenna and Sanja Mirkov

McKenna’s Drug Handbook for Nursing and Midwifery Lisa McKenna & Sanja Mirkov

Sample Contents

Chapter 3 Drug Therapy in the Older Adult

Chapter 59 Muscle Relaxants

Chapter 97 Antivenoms

Chapter 98 Diagnostic Preparations

McKenna’s Drug Handbook for Nursing and Midwifery - Seventh Edition - Lisa McKenna PhD, MEdSt, RN, RM Sanja Mirkov BPharm, PGDip Pub Hth

3 Drug therapy in the older adult

diminished activity of certain liver enzymes. When an older person takes certain sleep medications, such as nitrazepam, reduced liver metabolisation of the drug may cause a hangover effect the next morning. Decreased hepatic function may lead to the following: • more intense drug effects due to higher blood levels • longer-lasting drug effects due to prolonged blood concentrations • greater incidence of drug toxicity. Renal function Although an older person’s renal function is usually sufficient to eliminate excess body fluid and waste, the ability to elimi- nate some medications may be reduced by 50%or more. Manymedications commonly used by older adults, such as digoxin, are excreted primarily through the kidneys. If renal excretion of the drug decreases, high blood concentrations may result. Digoxin toxicity, therefore, is relatively common in older adults who are not receiving a reduced digoxin dosage to accommodate decreased renal function. Drug dosages can be modified to com- pensate for age-related decreases in renal function. Aided by laboratory tests, such as urea and serum creatinine, prescribers may adjust medication dosages so that the person receives the expected therapeutic benefits without the risk of toxicity. Since creatinine is a by-product of musclemetab- olism, in older individuals serum creatinine may remain in the normal range despite a falling glomerular filtration rate because of low muscle mass. Thus, elderly people should be considered as having impaired renal function and their drug dosage should generally be substantially lower than for younger people. It is common to start with about 50% of the adult dose.

If you are providing drug therapy for older adults, you will want to understand physi- ological and pharmacokinetic changes that may alter appropriate drug dosage or cause common adverse reactions or compliance problems in these people. Physiological changes As a person ages, gradual physiological changes occur. Some of these age-related changesmay alter the therapeutic and toxic effects of medications. Body composition Proportions of fat, lean tissue and water in the body change with age.Total body mass and lean body mass tend to decrease; the proportion of body fat tends to increase. Varying from person to person, these changes in body composition affect the relationship between a drug’s concen- tration and distribution in the body. For example, a water-soluble drug, such as gen- tamicin, is not distributed to fat. Because there is relatively less lean tissue in an older person, more of a drug remains in the blood. GI function In older adults, decreases in gastric acid secretion and GI motility slow the emptying of stomach contents and the movement of intestinal contents through the entire tract. Furthermore, research suggests that older adults may have more difficulty absorbing medications.This is a particularly significant problemwith drugs having a narrow thera- peutic range, such as digoxin, in which any change in absorption can be crucial. Hepatic function The ability of the liver tometabolise certain drugs decreases with age because of dimin- ished blood flow to the liver—a result of the age-related decrease in cardiac output and

14      General information

Be sure to observe the individual for signs or symptoms of toxicity. A person receiv- ing digoxin, for example, may experience anorexia, nausea, vomiting or confusion. Adverse drug reactions Compared with younger people, older adults experience twice as many adverse drug reactions because of multiple-drug therapy, poor compliance and physiologi- cal changes. Signs and symptoms of adverse drug reactions—confusion, weakness and lethargy—are commonlymistaken for senil- ity or indications of disease. If the adverse reaction is not identified, the person may continue to receive the drug. Furthermore, the person may receive unnecessary addi- tional medication to treat complications caused by the original medication. This may lead to a pattern of inappropriate and excessive medication use. Although any medication can cause adverse reactions, themost serious reactions in the older adult are causedby relatively few medications.Beparticularlyalertfortoxicities resulting from diuretics, antihypertensives, digoxin, corticosteroids, anticoagulants, sleeping aids and nonprescription drugs. Diuretic toxicity Because total body water content decreases with age, normal dosages of potassium- wasting diuretics, such as hydrochlorothia- zide and frusemide, may result in fluid loss and even dehydration in an older person. These diuretics may deplete serum potas- sium, causing weakness, and may elevate blood uric acid and glucose levels, com- plicating pre-existing gout and diabetes mellitus. Antihypertensive toxicity Many older adults experience light- headedness or fainting when using antihy- pertensive medications, partly in response to atherosclerosis and decreased elasticity of blood vessels. Antihypertensive drugs may reduce blood pressure too rapidly, resulting in dizziness or fainting.

Consequently, dosages of antihyperten- sive drugs must be carefully individualised. In older adults, overly aggressive treatment of high blood pressure may do more harm thangood, so treatment goals shouldbe rea- sonable. Although bringing blood pressure down to 120/85 mmHg may be appropri- ate in a young hypertensive person, a more reasonable goal for an older hypertensive person might be 150/95 mmHg. Digoxin toxicity As the body’s renal function and excretion rate decline, digoxin concentrations in the blood may build to toxic levels, causing nausea, vomiting, diarrhoea and—most seriously—cardiac arrhythmias. Try to pre- vent severe toxicity by monitoring serum drug levels and by observing the person for early signs or symptoms, such as appetite loss or visual disturbances. Corticosteroid toxicity Older adults on corticosteroids may expe- rience short-term effects, including fluid retention and psychological manifestations ranging from mild euphoria to acute psy- chotic reactions. Long-term toxic effects, such as osteoporosis, can be especially severe in older adults who have been taking prednisone or related steroidal compounds for months or even years. To prevent seri- ous toxicity, carefully monitor individuals on long-term regimens. Observe them for subtle changes in appearance, mood and mobility; signs of impaired healing; and fluid and electrolyte disturbances. Anticoagulant effects Older adults taking anticoagulants have an increased risk of bleeding, especially when they take NSAIDs concomitantly (as many do). Observe the INR carefully, and monitor the person for bruising and other signs of bleeding. Sleeping-aid toxicity Sedatives or sleeping aids, such as nitraz- epam, may cause excessive sedation or

Drug therapy in the older adult     15

with themedical regimen. However, in older adults, specific factors linked to ageing— such as diminished visual acuity, hearing loss, forgetfulness, the common need for multiple drug therapy and various socio- economic factors—can combine to make adherence a special problem. Approxi- mately one-third of older adults fail to comply with their prescribed drug therapy. They may fail to take prescribed doses or to follow the correct schedule, or they may take medications prescribed for previous disorders, discontinue medications prema- turely or use as-needed medications indis- criminately. Older adults who havemultiple prescriptions for the same medication may inadvertently take an overdose. Review each individual’s medication regimen with them. Make sure the person understands the amount of medication to take and the time and frequency of doses. Also explain how the person should take each medication—that is, with food or water or by itself. Give the person whatever help you can to avoid drug therapy problems. Suggest that they use drug calendars, pill ‘sort- ers’ or other aids to help in compliance, and refer the person to the prescriber or pharmacist if further information is needed.

residual drowsiness. Keep in mind that ingestion of alcohol may exaggerate such depressant effects, even if the sleeping aid was taken the previous evening. Nonprescription drug toxicity When aspirin, aspirin-containing analgesics and other nonprescription NSAIDs (ibu- profen, naproxen) are used in moderation, toxicity is minimal. However, prolonged ingestion may cause GI irritation—even ulcers—and gradual blood loss resulting in severe anaemia. Prescription NSAIDs may cause similar problems, especially with older adults. Although anaemia from chronic aspirin consumption can affect all age groups, older adults may be less able to compensate because of their already reduced iron stores. Laxatives may cause diarrhoea in older adults who are extremely sensitive to such drugs as bisacodyl. Chronic oral use of min- eral oil as a lubricating laxative may result in lipid pneumonia from aspiration of small residual oil droplets in the person’s mouth. Individual non-adherence Poor adherence can be a problemwith indi- viduals of any age. A significant number of hospitalisations result fromnon-adherence

59 Muscle relaxants baclofen dantrolene sodium mebeverine hydrochloride orphenadrine (See Chapter 60, ANTIPARKINSONian DRUGS ) ropinirole (See Chapter 60, ANTIPARKINSONian DRUGS )

severity or frequency of muscle spasm or reduced muscle tone should appear within 4–8 hours. If response is inadequate, second test dose of 75mcg/1.5mL is given 24 hours after first. If response is still inadequate, final test dose of 100 mcg/2 mL is given 24 hours later. Individuals unresponsive to 100-mcg dose should not be considered candidates for implantable pump. Maintenance therapy— Initial dose is titrated based on screening dose that elicited an adequate response.This effective dose is doubled and administered over 24 hours. However, if screening dose efficacy was maintained for 12 hours or longer, dose is not doubled. After first 24 hours, dose is increased slowly as needed and tolerated by 10–30% daily. During prolonged maintenance therapy, daily dose may be increased by 10–40% if needed; if person experiences adverse effects, dosage may be decreased by 10–20%. Maintenance dosages have ranged from 12 to 1500 mcg daily; however, experience with dosages over 1000 mcg daily is limited. Most individuals need 300 to 800mcg daily. Adjust-a-dose: For individuals with impaired renal function, oral and intrathecal dose must be decreased. Action Hyperpolarises muscle fibres to reduce impulse transmission. Appears to reduce transmission of impulses from spinal cord to skeletal muscle. Route Onset Peak Duration PO Hrs–wks 2–3 hrs Unknown Intrathecal 0.5–1 hr 4 hrs 4–8 hrs Adverse reactions CNS: drowsiness, dizziness, headache, weak­ ness,fatigue, hypotonia, confusion, insomnia, dysarthria, seizures.

Combination products None.

baclofen Clofen, Lioresal, Lioresal Intrathecal, Pacifen, Stelax Pregnancy risk category B3 Use in sport: Permitted Available forms Intrathecal injection: 0.5 mg/mL, 10 mg/5 mL, 10 mg/20 mL Tablets: 10 mg, 25 mg Indications & dosages ➤ Spasticity in multiple sclerosis, spinal cord injury— Adults: Initially, 5mg PO t.i.d. for 3 days, then 10 mg t.i.d. for 3 days, 15 mg t.i.d. for 3 days, 20 mg t.i.d. for 3 days. Dosage increased based on response, up to maximum of 80 mg daily. ➤ Management of severe spasticity in individuals who do not respond to or cannot tolerate oral baclofen therapy— Adults: Screening phase— After test dose to check responsiveness, drug is given by implantable infusion pump. Test dose is 1 mL of a 50-mcg/mL dilution administered into intrathecal space by barbotage over 1 minute or more. Significantly decreased

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

Muscle relaxants     781

CV: hypotension, hypertension. ENT: nasal congestion, slurred speech. Eye: blurred vision. GI: nausea, constipation, vomiting. GU: urinary frequency. Hepatic: increased AST and alkaline phos­ phatase levels. Metabolic: hyperglycaemia, weight gain. Respiratory: dyspnoea. Skin: rash, pruritus, excessive sweating. Interactions Drug-drug. Antihypertensives: Additiveeffects. Adjust antihypertensive dosage accordingly. CNS depressants: Increased CNS depression. Avoid use together. Levodopa/carbidopa: Possible mental confusion, hallucinations, headaches, nausea and agitation. Monitor closely. Lithium: Aggravatedhyperkineticsymptoms. Monitor closely. MAO inhibitors: Increased CNS depression and hypotension. Use cautiously and consider reduced dose. Tricyclic antidepressants: Increased effects of baclofen and increasedmuscular hypotonia. Monitor closely. Drug-lifestyle. Alcohol use: Increased CNS depression. Advise person to avoid alcohol use. Contraindications Contraindicated in individualshypersensitive to drug. care considerations • Use cautiously in individuals with impaired renal function or seizure disorders or when spasticity is used tomaintainmotor function. • Consider reduced dose in elderly adults and in individuals with renal impairment. • Give oral form with meals or with milk to prevent GI distress. • Orally administered drug should not be used to treat muscle spasm caused by rheumatic disorders, cerebral palsy, Parkinson’s disease or CVA because efficacy has not been established.

• Do not administer intrathecal injection by IV, IM, SC or epidural route. • Watch for sensitivity reactions, such as fever, skin eruptions and respiratory distress. • Anticipate increased risk of seizures in individuals with seizure disorder. • Amount of relief determines whether dosage (and drowsiness) can be reduced. • Do not withdraw drug abruptly after long-term use unless required by adverse reactions; may trigger hallucinations or rebound spasticity. • Experience with long-term intrathecal use suggests that about 10% of individuals may develop tolerance to drug. In some cases, this may be treated by hospitalising person and slowly withdrawing drug over 2-week period. Patient teaching • Instruct person to take oral form with meals or milk to prevent GI distress. • Advise person to avoid activities that require alertness until drug’s CNS effects are known. Drowsiness is usually transient. • Advise person to avoid alcohol when taking drug. • Instruct person to follow prescriber’s orders regarding rest and physical therapy.

dantrolene sodium Dantrium, Dantrium IV Pregnancy risk category B2 Use in sport: Permitted Available forms Capsules: 25 mg, 50 mg Powder for injection: 20 mg/vial Indications & dosages

➤ Spasticityandsequelaesecondarytosevere chronic disorders (such as multiple sclerosis, cerebral palsy, spinal cord injury, CVA)— Adults: 25mg PO daily. Increased gradually in 25-mg increments, up to 100 mg b.i.d. to q.i.d., to maximum of 400 mg daily.

782      Musculoskeletal drugs

CV: tachycardia, erratic blood pressure. ENT: speech disturbance. Eye: excessive lacrimation, diplopia, visual disturbances. GI: anorexia, constipation, cramping, dys­ phagia, metallic taste, severe diarrhoea, GI bleeding. GU: urinary frequency, haematuria, incontin­ ence, nocturia, dysuria, crystalluria, difficult erection, urine retention, increased urea level. Hepatic: hepatitis , increased ALT, AST, alkaline phosphatase, LDH and total serum bilirubin levels. Musculoskeletal: myalgia, back pain, muscle weakness . Respiratory: pleuraleffusionwithpericarditis. Skin: eczematouseruption,pruritus,urticaria, abnormal hair growth, sweating. Other: chills. Interactions Drug-drug. CNSdepressants: Increased CNS depression. Avoid use together. Oestrogens: Possible increased risk of hepatotoxicity. Use together cautiously. Verapamil: Possible CV collapse with IV verapamil. Stop verapamil before administ­ ering IV dantrolene. Drug-lifestyle. Alcohol use: Increased CNS depression. Caution person to avoid alcohol use. Sunexposure: Photosensitivity and increased risk of sunburn. Advise person to take precautions and to avoid excessive sunlight. Contraindications Contraindicated in individuals when spasticity is used tomaintainmotor function orforspasms inrheumaticdisorders; inthose with uppermotor neuron disorders or active hepatic disease; and in women who are breastfeeding. care considerations • Use cautiously in individuals with severely impaired cardiac or pulmonary function or pre-existing hepatic disease, inwomen and in individuals older than 35 years.

Children: Initially, 0.5 mg/kg PO b.i.d., increasedtot.i.d.,thenq.i.d.Dosageincreased, p.r.n., by 0.5 mg/kg daily to 3 mg/kg b.i.d. to q.i.d. Maximumdosage is 100 mg q.i.d. ➤ Management of malignant hyperthermia crisis— Adults and children: 1 mg/kg IV initially; dose repeated, p.r.n., up to cumulative dosage of 10 mg/kg. ➤ Prevention or attenuation of malignant hyperthermia crisis in susceptible individuals who require surgery— Adults: 4–8 mg/kg PO daily in three to four divided doses for 1–2 days before procedure. Final dose administered 3–4 hours before procedure. ➤ Prevention of recurrence of malignant hyperthermia crisis— Adults: 4–8 mg/kg daily PO in four divided doses for up to 3 days after hyperthermic crisis. IV administration • Give as soon as malignant hyperthermia reaction is recognised. • Reconstitute each vial by adding 60 mL of sterile water for injection and shaking vial until clear. Do not use a diluent that contains a bacteriostatic agent. • Watch for irritation and infiltration; extravasation can cause tissue damage and necrosis. • Protect contents from light and usewithin 6 hours. Action Acts directly on skeletal muscle to interfere with intracellular calcium movement by decreasing excitation and contraction coupling and reducing muscle strength. Route Onset Peak Duration PO Unknown 5 hrs Unknown IV Unknown Unknown Unknown Adverse reactions CNS: drowsiness, dizziness, fever, light- headedness, malaise, fatigue, headache, confusion, nervousness, insomnia, seizures.

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

Muscle relaxants     783

Action Antimuscarinic. Antispasmodic and smooth muscle relaxant. Route Onset Peak Duration PO Unknown 13 hrs 24 hrs Adverse reactions CNS: dizziness, headache, insomnia, malaise. CV: bradycardia. GI: nausea, constipation, dyspepsia, heartburn. Metabolic: anorexia. Skin: facial oedema, urticaria. Other: angio-oedema , anaphylaxis , hyper- sensitivity reaction. Interactions None reported. Contraindications Contraindicated in individuals with hyper­ sensitivity to the drug or other components of the preparation and in those with severe hepatic impairment. care considerations • Use cautiously in individuals with cardiac arrhythmia, heart block, angina, ischaemic heart disease or liver or renal impairment. • Liver function tests should be performed regularly in individualswith liver impairment. • Preparation contains lactose and sucrose so caution is required in individuals with potential intolerance or relevantmalabsorp­ tion syndrome. • Not recommended in the first trimester of pregnancy. Patient teaching • Advise person to take drug at the same time each day, 20 minutes before meals. • Warn person to avoid driving and other hazardous activities until CNS effects of drug are known. • Instruct person to continue taking the medication, even if feeling well.

• Obtain liver function test results at begin­ ning of therapy. • Prepare oral suspension for single dose by dissolving capsule contents in juice or other liquid. For multiple doses, use acid vehicle and refrigerate. Use within several days. • Watch for hepatitis (fever and jaundice), severe diarrhoea, severe weakness or sensit­ ivity reactions (fever and skin eruptions). Withhold dose and notify prescriber if these occur. • Amount of relief in individual determines whether dosage (and drowsiness) can be reduced. Patient teaching • Instruct person to take drugwithmeals or milk in four divided doses. • Advise person to use cautionwhen eating to avoid choking. Some individuals may experience difficulty swallowing during therapy. • Warn person to avoid driving and other hazardous activities until CNS effects of drug are known. • Advise person to avoid combining drug with alcohol and other CNS depressants. • Instruct person to avoid photosensitivity reaction by using sunblock and wearing protective clothing, to report abdominal discomfort or GI problems immediately and to follow prescriber’s orders regarding rest and physical therapy. mebeverine hydrochloride Colese, Colofac Pregnancy risk category B2 Use in sport: Permitted Available form Tablets: 135 mg Indications & dosages ➤ Managementofirritablebowelsyndrome— Adults: 135 mg PO t.i.d.

97 Antivenoms

black snake antivenom box jellyfish antivenom brown snake antivenom death adder antivenom funnel-web spider antivenom redback spider antivenom sea snake antivenom stonefish antivenom taipan antivenom tiger snake antivenom Combination products

Route Onset

Peak

Duration

IV

Unknown Unknown Unknown

Adverse reactions CNS: headache. GI: abdominal pain, diarrhoea, nausea, vomiting. Skin: injection site reaction, urticaria, rash. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Black snake venom contains neurotoxins, myolytic and anticoagulant toxins. • Monitor FBC, platelets, INR and aPTT on presentation, immobilisation (if used) and 6 hours thereafter. • Monitor for signs and symptoms of bleeding (bruising, bleeding fromgums and venepuncturesites,epistaxis,gastrointestinal bleeding, haematuria, altered mental status suggesting intracranial haemorrhage). • In individuals with severe consumptive coagulopathy, fresh frozen plasma and/ or cryoprecipitate should be considered early. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Not administered by IM injection. • Venom detection kits should be used to detect and identify specific venom at the bite site or in urine where possible. • Anaphylactic reactions may be more likely in individuals who are atopic or have previously received equine serum.

P olyvalent snake antivenom concentrate for infusion : brown snake antivenom 1000 U, tiger snake antivenom 3000 U, death adder antivenom6000 U, taipan antivenom 12,000 U and king brown snake antivenom 18,000 U. black snake antivenom Black Snake Antivenom Infusion Pregnancy risk category NR Use in sport: Permitted Available form Solution for infusion: 18,000 U/vial Indications & dosages ➤ Treatment of systemic king brown or mulga snakeenvenoming— Adults: 18,000 U by slow IV infusion diluted 1 in 10 in Hartmann’s solution, repeated if necessary. Children: 18,000 U by slow IV infusion diluted 1 in 5 in Hartmann’s solution, repeated if necessary. Action Antivenomeffective against venomof black snake and other members of the Pseudechis genus such as red-bellied black snake or common black snake.

1288      Miscellaneous drug categories

Action Antivenom against toxin of box jellyfish ( Chironex fleckeri) found in Australian tropical waters. Route Onset Peak Duration IV Unknown Unknown Unknown Adverse reactions Skin: urticaria, rash. Other: allergic reactions, anaphylaxis , delayed serum sickness . Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming or extensive local involvement with intractable pain. care considerations • Box jellyfish venom contains toxins that affect the myocardium and neuromuscular functioning of the respiratory system and cause dermatonecrosis. In severe cases, death can occur in as little as 20 minutes. • Antivenom should be administered as soon as possible after cardiopulmonary resuscitation has commenced. • Not all individuals stung by box jellyfish will require antivenom. • As product is sourced from ovine plasma, potential for transmission of infectious disease cannot be ruled out. • Not administered by IM injection. • Venom detection kits should be used to detect and identify specific venom at the bite site or in urine where possible. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions.

• Although considered controversial, individuals at risk of anaphylactic reactions may be given premedication with adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Althougheffectiveagainstother Pseudechis genus members, tiger snake antivenom is usually the preferred treatment. • Monitor the person closely for at least 6 hours after administering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instructpersontoreportanyadverseeffects —such as shortness of breath, itching, skin swelling, fever or chest pain—immediately. box jellyfish antivenom Box Jellyfish Antivenom Solution for Injection Pregnancy risk category NR Use in sport: Permitted Available form Solution for injection: 20,000 U/vial Indications & dosages ➤ Treatmentofboxjellyfishstingdemonstrating systemic envenoming or extensive local involvement— Adults: 20,000 U by slow IV infusion diluted 1 in 10 with Hartmann’s solution, repeated if necessary. Children: 20,000 U by slow IV infusion diluted 1 in 5 with Hartmann’s solution, repeated if necessary.

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

Antivenoms     1289

GI: abdominal pain, diarrhoea, nausea, vomiting. Skin: injection site reaction, urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Brown snake venomcauses rapid coagulo­ pathythatmaybeassociatedwithrespiratory paralysis and thrombocytopenia. • Monitor FBC, platelets, INR and aPTT on presentation, immobilisation (if used) and 6 hours thereafter. • Monitor for signs and symptoms of bleeding (bruising, bleeding fromgums and venepuncturesites,epistaxis,gastrointestinal bleeding, haematuria, altered mental status suggesting intracranial haemorrhage). • In individuals with severe consumptive coagulopathy, fresh frozen plasma and/or cryoprecipitate should be considered early. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Not administered by IM injection. • Venom detection kits should be used to detect and identify specific venom at the bite site or in urine where possible. • Anaphylactic reactions may be more likely in individuals who are atopic or have previously received equine serum. • Although considered controversial, individuals at risk of anaphylactic reactions maybegivenpremedicationwithadrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit.

• Vinegar should be applied liberally to tentacles stuck to the skin in order to prevent greater spread of venom from nematocysts. Patient teaching • Advise person of risk of possible infectious disease transmission as venom sourced from sheep serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. brown snake antivenom Brown Snake Antivenom Infusion Pregnancy risk category NR Use in sport: Permitted Available form Solution for infusion: 1000 U/vial Indications & dosages ➤ Treatment of Pseudonaja genus snake envenoming— Adults: 1000 U by slow IV infusion diluted 1 in 10 in Hartmann’s solution, repeated if necessary. Individuals with severe systemic envenoming may require several vials of antivenom. Most individuals require 3 vials and the use of 13 vials has been recorded. Children: 1000 Uby slow IV infusion diluted 1 in 5 in Hartmann’s solution, repeated if necessary. Action Antivenomeffectiveagainstvenomofbrown snake and othermembers of the Pseudonaj a genus such as Eastern brown snake, dugite and gwardar (Western brown snake). Route Onset Peak Duration IV Unknown Unknown Unknown

Adverse reactions CNS: headache.

1290      Miscellaneous drug categories

Adverse reactions CNS: headache. GI: abdominal pain, diarrhoea, nausea, vomiting. Skin: injection site reaction, urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Death adder venom contains neurotoxins that induce paralysis. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Not administered by IM injection. • Venom detection kits should be used to detect and identify specific venom at the bite site or in urine where possible. • Anaphylactic reactions may be more likely in individuals who are atopic or have previously received equine serum. • Although considered controversial, indi­ viduals at risk of anaphylactic reactions may be givenpremedicationwith adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifested by albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely after admin­ istering antivenom.

• Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely after admin­ istering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. death adder antivenom Death Adder Antivenom Concentrate for Infusion Pregnancy risk category NR Use in sport: Permitted Available form Solution for infusion: 6000 U/vial Indications & dosages ➤ Treatment of systemic envenoming from deathadderbite— Adults: 6000 U by slow IV infusion diluted 1 in 10 in Hartmann’s solution, repeated if necessary. Individuals with severe systemic envenoming may require several vials of antivenom; use up to 5 vials has been reported. Children: 6000 Uby slow IV infusion diluted 1 in 5 in Hartmann’s solution, repeated if necessary. Action Antivenom effective against venom of death adder (Acanthophis antarcticus ). Route Onset Peak Duration IV Unknown Unknown Unknown

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

Antivenoms     1291

Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. funnel-web spider antivenom Funnel-Web Spider Antivenom Pregnancy risk category NR Use in sport: Permitted Available form Powder for injection: 125 U/vial Indications & dosages ➤ Treatment of systemic envenoming from funnel-webspiderbite— Adults and children: 250 U by slow IV injection. Each vial should be reconstituted in 10mL water for injections BP; repeat after 15 minutes if required. IV administration • To prepare IV injection, dilute calculated dose in water for injections. • Swirl gently to fully dissolve powder. • A clear to slightly opalescent colourless solution should be achieved in 10 minutes. • Solution should be used immediately. • Administer by slow IV injection. Action Antivenom. Purified immunoglobulin sourcedfromrabbitplasma,effectiveagainst venomof funnel-web spider (Atraxrobustus). Route Onset Peak Duration IV Unknown Unknown Unknown Adverse reactions Skin: urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness .

Interactions None reported. Contraindications

Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • As product is sourced from rabbit plasma, potential for transmission of infectious disease cannot be ruled out. • Not administered by IM injection. • Venom detection kits should be used to detect and identify specific venom at the bite site or in urine where possible. • Anaphylactic reactions may be more likely in individuals who are atopic or have previously received rabbit serum. • Although considered controversial, indi­ viduals at risk of anaphylactic reactions may be givenpremedicationwith adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely after admin­ istering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from rabbit serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately.

1292      Miscellaneous drug categories

weeks and there are reports of satisfactory use of the antivenom to alleviate these symptoms up to 10 days after a confirmed redback spider bite. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Anaphylactic reactions may be more likely in individuals who are atopic, have previously received equine serum or are receiving antivenom by IV route. • Although considered controversial, indi­ viduals at risk of anaphylactic reactions may be given premedication with adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely after admin­ istering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. sea snake antivenom Sea Snake Antivenom Concentrate for Infusion Pregnancy risk category NR Use in sport: Permitted Available form Solution for infusion: 1000 U/vial

redback spider antivenom Redback Spider Antivenom Solution for Injection Pregnancy risk category NR Use in sport: Permitted Available form Solution for infusion: 500 U/vial Indications & dosages ➤ Treatment of systemic envenoming from redbackspiderbite— Adults and children: 500 U by IM injection. In case of severe envenoming, may be given by IV injection diluted 1:10 in Hartmann’s solution. If venom’s effects not completely reversed after 2 hours, a second injection of antivenom may be administered. Action Antivenom derived from horse plasma, effective against venom from redback spider ( Latrodectus hasselti ). Route Onset Peak Duration IV Unknown Unknown Unknown IM Unknown Unknown Unknown Adverse reactions CNS: headache. Skin: injection site reaction, urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, lympha­ denopathy, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • The effects of the venom, particularly severe pain, may persist for days or even

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

Antivenoms     1293

Indications & dosages ➤ Treatment of systemic envenoming fromsea snakebite— Adults: 1000 U by slow IV infusion diluted 1 in 10 in Hartmann’s solution or normal saline, repeated if necessary. In severe envenoming, doses up to 10,000 units may be used. Children: 1000 Uby slow IV infusion diluted 1 in 5 in Hartmann’s solution or normal saline, repeated if necessary. Action Antivenom effective against venom Enhydrina schistosa and, to varying effect, other sea snakes present in northern Australian waters. Route Onset Peak Duration IV Unknown Unknown Unknown Adverse reactions CNS: headache. GI: abdominal pain, diarrhoea, nausea, vomiting. Skin: injection site reaction, urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Sea snake venom contains potent neuro­ toxins that cause muscle paralysis and respiratory failure, as well as myolytic prop­ erties causing myalgia, muscle weakness, trismus, ptosis, ophthalmoplegia, hyper­ kalaemia and renal failure in severe cases. • Myolysis causes elevation of serum glutamic oxaloacetic transaminase (SGOT), which can be used to determine or monitor the degree of envenoming.

• Monitor renal function, urine output, serum electrolytes and urinalysis. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Not administered by IM injection. • Venom detection kits should be used to detect and identify specific venom at the bite site or in urine where possible. • Anaphylactic reactions may be more likely in individuals who are atopic or have previously received equine serum. • Although considered controversial, indi­ viduals at risk of anaphylactic reactions may be givenpremedicationwith adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely for at least 6 hours after administering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. stonefish antivenom Stonefish Antivenom Solution for Injection Pregnancy risk category NR Use in sport: Permitted Available form Solution for injection: 2000 U/vial

1294      Miscellaneous drug categories

Indications & dosages ➤ Treatment of systemic envenoming from stonefish— Adults: Dose depends on number of visible puncture sites:

• Injection of local anaesthetic around the sting or a regional block may help reduce the pain. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Anaphylactic reactions may be more likely in individuals who are atopic, have previously received equine serum or are receiving antivenom by IV route. • Although considered controversial, indi­ viduals at risk of anaphylactic reactions may be givenpremedicationwith adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely for at least 6 hours after administering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. taipan antivenom Taipan Antivenom Pregnancy risk category NR Use in sport: Permitted Available form Solution for injection: 12,000 U/vial Indications & dosages ➤ Treatment of systemic envenoming from taipanbite—

1–2 sites—2000 U (1 vial) 3–4 sites—4000 U (2 vials) 5 or more sites—6000 U (3 vials)

Usually administered IM; however, may be administered by IV infusion in extremely severe cases. Action Antivenom effective against venom of stonefish ( Synanceia verrucosa and/or Synanceia horrida ) found in Australian

tropical waters. Route Onset

Peak

Duration

IV

Unknown Unknown Unknown

IM Unknown

Unknown Unknown

Adverse reactions Skin: injection site reaction, urticaria, rash. Other: allergic reactions, anaphylaxis , delayed serum sickness . Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Stonefish venom contains an enzyme causing extensive local oedema, as well as systemic effects including pulmonary oedema, bradycardia, arrhythmias, fever, hypotension, muscle weakness and paralysis. • As the toxin is heat-labile, immersion of the limb in hot water (50 ° C) should be undertaken first as this usually gives some pain relief. The temperature of the water should be judged by the attendant to avoid scalding.

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

Antivenoms     1295

Adults and children: 12,000 U by slow IV infusion diluted 1 in 10 in Hartmann’s solution or normal saline, repeated if necessary. Individuals with severe systemic envenoming may require up to 8 vials. Action Antivenomeffectiveagainstvenomoftaipan snake ( Oxyuranus scutellatus , Oxyuranus microlepidotus , Oxyuranus scutellatus canni) . Route Onset Peak Duration IV Unknown Unknown Unknown Adverse reactions CNS: headache. GI: abdominal pain, nausea, vomiting. Skin: injection site reaction, urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Taipan venom contains neurotoxin that causes respiratory paralysis, myolytic toxin and coagulant, which converts prothrombin to thrombin, which in turn produces a secondary afibrinogenaemia with resultant haemorrhage. Myolytic toxin causes myalgia, muscle weakness, trismus, ptosis, ophthalmoplegia, hyperkalaemia and renal failure in severe cases. • Monitor vital signs, neurological and mental status and evidence of respiratory depression. • Monitor FBC, platelets, INR and aPTT on presentation, immobilisation (if used) and 6 hours thereafter. • Monitor for signs and symptoms of bleeding (bruising, bleeding fromgums and venepuncturesites,epistaxis,gastrointestinal

bleeding, haematuria, altered mental status suggesting intracranial haemorrhage). • Monitor renal function, urine output, serum electrolytes and urinalysis. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Anaphylactic reactions may be more likely in individuals who are atopic, have previously received equine serum or are receiving antivenom by IV route. • Although considered controversial, individuals at risk of anaphylactic reactions may be given premedication with adrenaline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely for at least 6 hours after administering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately. tiger snake antivenom Tiger Snake Antivenom Concentrate for Infusion Pregnancy risk category NR Use in sport: Permitted Available form Solution for injection: 3 000 U/vial

1296      Miscellaneous drug categories

Indications & dosages ➤ Treatmentofsystemicenvenomingfromtiger snake, copperhead snake, black snake, Collett’s snakeorrough-scaledsnakebite— Adults and children: 3000 U by slow IV infusion diluted 1 in 10 in Hartmann’s solution, repeated if necessary. Action Antivenom effective against venom of tiger snake ( Notechis scutatus) , copperhead snakes ( Austrelaps spp.), black snakes ( Pseudechis spp.), Collett’s snake ( Pseudechis colletti ) and rough-scaled snake ( Tropidechis carinatus ). Route Onset Peak Duration IV Unknown Unknown Unknown Adverse reactions CNS: headache. GI: abdominal pain, nausea, vomiting. Skin: injection site reaction, urticaria, rash. Musculoskeletal: chest pain, myalgia. Other: allergic reactions, anaphylaxis , delayed serum sickness , chills, pyrexia. Interactions None reported. Contraindications Should not be used unless there is evidence of systemic envenoming with potential for serious toxic effects. care considerations • Tiger snake venom contains neurotoxins that cause respiratory paralysis, myolytic toxin and coagulant, which converts prothrombin to thrombin, which in turn produces a secondary afibrinogenaemia with resultant haemorrhage. Myolytic toxin causes myalgia, muscle weakness, trismus, ptosis, ophthalmoplegia, hyperkalaemia and renal failure in severe cases.

• Monitor vital signs, neurological and mental status and evidence of respiratory depression. • Monitor FBC, platelets, INR and aPTT on presentation, immobilisation (if used) and 6 hours thereafter. • Monitor for signs and symptoms of bleed­ ing (bruising, bleeding from gums and venepuncturesites,epistaxis,gastrointestinal bleeding, haematuria, altered mental status suggesting intracranial haemorrhage). • Monitor renal function, urine output, serum electrolytes and urinalysis. • As product is sourced from horse plasma, potential for transmission of infectious disease cannot be ruled out. • Anaphylactic reactions may be more likely in individuals who are atopic, have previously received equine serum or are receiving antivenom by intravenous route. • Although considered controversial, individuals at risk of anaphylactic reactions may be given premedication with adren­ aline and antihistamine. • Have adrenaline 1:1000 available in case of anaphylactic reaction. • Severe cases should be managed in intensive care unit. • Monitor for delayed serum sickness within 8–13 days after the administration of antivenom, manifestedby albuminaemia, arthralgia, fever, lymphadenopathy and skin eruptions. • Monitor the person closely for at least 6 hours after administering antivenom. Patient teaching • Advise person of risk of possible infectious disease transmission as venom is sourced from horse serum. • Instruct person to report any adverse effects—such as shortness of breath, itching, skin swelling, fever or chest pain— immediately.

Reactions may be common , uncommon, life-threatening , or commonandlife-threatening.

98 Diagnostic preparations

exametazime gadobenate dimeglumine gadobutrol gadodiamide

Adults: 350–500 MBq IV. Dynamic imaging may be performed between 0 and 10 minutes following injection. Static imaging may be performed from 15 minutes up to 6 hours after injection. Action Diagnostic radiopharmaceutical preparation that assists detection of altered perfusion in areas of the cerebrum. Route Onset Peak Duration IV Immediate Unknown 6 hrs Adverse reactions CV: transient blood pressure elevation, vascular spasm. Skin: rash, urticaria. Other: facial or generalised oedema, fever, mild hypersensitivity. Interactions None reported. Contraindications Contraindicated in individuals with known hypersensitivity to the preparation. care considerations • Alert: Radioactive drug—drug must be handled with care and appropriate safety measures should be used to minimise radiation exposure to the individual and to staff. • Reconstituted agent must be used within 30 minutes. • Monitor blood pressure following procedure. • Due to potential for bladder radiation, encourage person to follow adequate hydration and to void straight after the procedure, then regularly thereafter. • Women who are breastfeeding should discontinue breastfeeding for at least

gadopentetate gadoteric acid gadoteridol gadoxetic acid iodixanol iohexol iomeprol

iopamidol iopromide ioversol meglumine iothalamate meglumine iotroxate metyrapone tetrofosmin thyrotrophin alfa Combination products

G astrografin ,M d -76,M d - gastroview :sodium diatrizoate 10% and meglumine diatrizoate 66%. U rografin 30%: sodium amidotrizoate 40 mg/mL and meglumine amidotrizoate 260 mg/mL. U rografin 76%: sodium amidotrizoate 100 mg/mL and meglumine amidotrizoate 660 mg/mL. exametazime Ceretec Pregnancy risk category C Use in sport: Permitted Available form Solution for injection: 0.5 mg/0.5 mL Indications & dosages ➤ Scintigraphic identification of seizure foci in individualswithtemporal lobeepilepsy—