McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 2 0 Anxiolytic and hypnotic agents

TABLE 20.3

DRUGS IN FOCUS Other anxiolytic/hypnotic drugs

Drug name

Usual indications

buspirone (Buspar)

Oral drug for anxiety disorders; off-label use; signs and symptoms of premenstrual syndrome Special considerations: may cause dry mouth, headache; use with caution in people with hepatic or renal impairment and in elderly people Administered PO or PR for nocturnal sedation, preoperative sedation Special considerations: withdraw gradually over 2 weeks in people maintained for weeks or months IV drug used for newly intubated and mechanically ventilated people in the intensive care unit Special considerations: do not use longer than 24 hours; monitor person continually PO, IM, or IV use to decrease the need for postoperative pain relief and for preoperative sedation Special considerations: an antihistamine; monitor injection sites carefully; monitor people for thickened respiratory secretions and breathing difficulties, a problem that can cause concern after anaesthesia Oral drug for sedation in children Special considerations: major component of dosage should be given at bedtime, or if daytime doses are ordered, give directly after meals Oral drug for short-term treatment of insomnia Special considerations: dispense the least amount possible to depressed and/or suicidal people; withdraw gradually if used for prolonged period; person should take before bed and devote 4–8 hours to sleep; use with caution in people with hepatic or renal impairment; elderly people are especially sensitive to these drugs—administer a lower dose and monitor these people carefully Oral drug for the treatment of insomnia Special considerations: tablet must be swallowed whole; instruct the person to take this drug just before bed and allow 8 hours for sleep

chloral hydrate (generic)

dexmedetomidine (Precedex)

promethazine (Phenergan)

trimeprazine (Vallergan)

zolpidem (Ambien, Stilnox)

zopiclone (Imovane)

indications and special considerations. Such medications include the following: • Antihistamines (promethazine [ Phenergan ] and trimeprazine [ Vallergan ] can be very sedating in some people. They are used as preoperative medications and postoperatively to decrease the need for narcotics. • Buspirone ( Buspar ) (not available in Australia) a newer antianxiety agent, has no sedative, anticonvulsant or muscle relaxant properties, and its mechanism of action is unknown. However, it reduces the signs and symptoms of anxiety without many of the CNS effects and severe adverse effects associated with other anxiolytic drugs. It is rapidly absorbed from the GI tract, metabolised in the liver and excreted in urine. • Chloral hydrate (generic) is frequently used to produce nocturnal sedation or preoperative sedation. Its mechanism of action is unknown. It is rapidly absorbed from the GI tract and metabolised in the liver and kidney for excretion in the bile and urine. • Dexmedetomidine ( Precedex ) is given intravenously at a starting dose of 1 mcg/kg over 10 minutes and then a controlled infusion for up to 24 hours. It is used for the sedation of newly intubated and mechanically ventilated people in an intensive care unit. • Zopiclone ( Imovane ) is a new agent used to treat insomnia. It is thought to react with GABA sites near

benzodiazepine receptors. It is rapidly absorbed, metabolised in the liver and excreted in the urine. • Zolpidem ( Stilnox ) (not available in New Zealand) is used for the short-term treatment of insomnia. It is thought to work by affecting serotonin levels in the sleep centre near the RAS. It is metabolised in the liver and excreted in the urine. CHAPTER SUMMARY ■■ Anxiolytics, or minor tranquillisers, are drugs used to treat anxiety by depressing the CNS. When given at higher doses, these drugs may be sedatives or hypnotics. ■■ Sedatives block the awareness of and reaction to environmental stimuli, resulting in associated CNS depression that may cause drowsiness, lethargy and other effects. This action can be beneficial when a person is very excited or afraid. ■■ Hypnotics further depress the CNS, particularly the RAS, to inhibit neuronal arousal and induce sleep. ■■ Benzodiazepines are a group of drugs used as anxiolytics. They react with GABA-inhibitory sites to depress the CNS. They can cause drowsiness, lethargy and other CNS effects.