McKenna's Pharmacology for Nursing, 2e

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P A R T 4  Drugs acting on the central and peripheral nervous systems

In addition, because of an enzyme-induction effect of barbiturates in the liver, the following drugs may not be as effective as desired: oral anticoagulants, digoxin, tricyclic antidepressants (TCAs), corticosteroids, oral contraceptives, oestrogens, paracetamol, metronidazole, carbamazepine, beta-blockers, griseofulvin, phenyl­ butazones, theophyllines, quinidine and doxycycline. If these agents are given in combination with barbitu- rates, people should be monitored closely; frequent dose adjustments may be necessary to achieve the desired therapeutic effect.

■■ Barbiturates are an older class of drugs used as anxiolytics, sedatives and hypnotics. Because they are associated with potentially serious adverse effects and interact with many other drugs, they are less desirable than the benzodiazepines or other anxiolytics. OTHER ANXIOLYTIC AND HYPNOTIC DRUGS Other drugs are used to treat anxiety or to produce hypnosis that do not fall into either the benzodiaze- pine or the barbiturate group. See Table 20.3 for a list of other anxiolytic/hypnotic drugs, including usual ■ ■ Taper dose gradually after long-term therapy, especially in people with epilepsy. Acute withdrawal may precipitate seizures or cause withdrawal syndrome in these individuals . ■ ■ Provide comfort measures to help people tolerate drug effects , including small, frequent meals; access to bathroom facilities; bowel program as needed; consuming food with the drug if GI upset is severe; and environmental control, safety precautions, orientation and appropriate skin care as needed. ■ ■ Provide thorough teaching, including drug name, prescribed dosage, measures for avoidance of adverse effects, and warning signs that may indicate possible problems. Instruct people about the need for periodic monitoring and evaluation to enhance knowledge about drug therapy and to promote compliance . ■ ■ Offer support and encouragement to help the person cope with the diagnosis and the drug regimen . Evaluation ■ ■ Monitor response to the drug (alleviation of signs and symptoms of anxiety, sleep, sedation, reduction in seizure activity). ■ ■ Monitor for adverse effects (sedation, hypotension, cardiac arrhythmias, hepatic or renal dysfunction, skin reactions, dependence). ■ ■ Evaluate the effectiveness of the teaching plan (person can give the drug name, dosage, possible adverse effects to watch for, specific measures to help avoid adverse effects and the importance of continued follow-up). ■ ■ Monitor the effectiveness of comfort measures and compliance with the regimen. KEY POINTS

Care considerations for people receiving barbiturates

Assessment: History and examination

■ ■ Assess for contraindications or cautions: known allergies to barbiturates to prevent hypersensitivity reactions or a history of addiction to sedative/ hypnotic drugs to avert a similar problem with these drugs ; impaired hepatic or renal function that could alter the metabolism and excretion of the drug ; cardiac dysfunction or respiratory dysfunction; seizure disorders, which could be exacerbated by these drugs ; acute or chronic pain disorders, which should be evaluated before using these drugs ; and pregnancy or breastfeeding, which would indicate a need for caution when using these drugs . therapy and for the occurrence of any potential adverse effects . Assess the following: temperature and weight; blood pressure and pulse, including perfusion; skin colour and lesions; affect, orientation and reflexes; respiratory rate and adventitious sounds; and bowel sounds. Implementation with rationale ■ ■ Do not administer these drugs intra-arterially because serious arteriospasm and gangrene could occur . Monitor injection sites carefully for local reactions . ■ ■ Do not mix IV drugs in solution with any other drugs to avoid potential drug–drug interactions . ■ ■ Give parenteral forms only if oral forms are not feasible or available, and switch to oral forms as soon as possible to avoid serious reactions or adverse effects . ■ ■ Give IV medications slowly because rapid administration may cause cardiac problems . ■ ■ Provide standby life-support facilities in case of severe respiratory depression or hypersensitivity reactions . ■ ■ Assess for baseline status before beginning