McKenna's Pharmacology for Nursing, 2e

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

desirable in people who are restless, nervous, irritable or overreacting to stimuli. Although sedation is anxio- lytic, it may frequently lead to drowsiness. For example, sedative-induced drowsiness is a concern for outpatients who need to be alert and responsive in their normal lives. On the other hand, this tiredness may be desirable for people who are about to undergo surgery or other procedures and who are receiving medical support. The choice of an anxiolytic drug depends on the situation in which it will be used, keeping the related adverse effects in mind. Hypnosis Extreme sedation results in further central nervous system (CNS) depression and sleep, or hypnosis . Hyp- notics are used to help people fall asleep by causing

sedation. Drugs that are effective hypnotics act on the reticular activating system (RAS) and block the brain’s response to incoming stimuli. Hypnosis, therefore, is the extreme state of sedation, in which the person no longer senses or reacts to incoming stimuli. BENZODIAZEPINES USED AS ANXIOLYTICS Benzodiazepines , the most frequently used anxiolytic drugs, prevent anxiety without causing much associ- ated sedation. In addition, they are less likely to cause physical dependence than many of the older sedatives/ hypnotics that are used to relieve anxiety. Table 20.1 lists the available benzodiazepines, including common indications and specific information about each drug.

TABLE 20.1

DRUGS IN FOCUS Benzodiazepines* used as anxiolytics

Drug name

Dosage/route

Usual indications

alprazolam (Xanax)

1.5–4.5 mg/day PO

Anxiety; panic attack Onset: 30 minutes Duration: 4–6 hours Special considerations: Taper after long-term therapy

bromazepam (Lexotan)

Adult: 3–12 mg PO t.d.s.

Anxiety, agitation Onset: 0.5–4 hours Duration: 12–24 hours

clobazam (Frisium)

Adult: 10–30 mg PO daily in single or divided dose

Acute anxiety, sleep disturbance Onset: 1–4 hours Duration: 17–49 hours

Adult: 2–10 mg PO b.d. or t.d.s. Paediatric (6 months–3 years): 1–6 mg/day Paediatric (4–14 years): 4–12 mg/day

Anxiety; alcohol withdrawal; muscle relaxant; antiepileptic; antitetanus; preoperative anxiolytic Onset: 5–60 minutes Duration: 3 hours Special considerations: Monitor injection sites; drug of choice if route change is anticipated; taper after long-term therapy Special considerations: Monitor injection sites; reduce dosage of narcotics given with this drug Anxiety; alcohol withdrawal Onset: slow Duration: 2–4 hours Special considerations: Preferred for elderly Hypnotic; treatment of insomnia Onset: varies Duration: 4–6 hours Special considerations: Taper after long-term therapy Hypnotic; treatment of insomnia Onset: varies Duration: 2–4 hours Special considerations: Monitor liver and renal function, FBC; taper after long-term therapy Anxiety; preanaesthesia anxiolytic Onset: 1–30 minutes Duration: 12–24 hours

diazepam (Valium)

lorazepam (Ativan)

1–10 mg/day PO in divided doses; or 0.05 mg/kg IM; or 0.044 mg/kg IV

oxazepam (Serepax)

10–15 mg PO t.d.s. to q.i.d.

temazepam (Normison)

10–30 mg PO at bedtime

triazolam (Halcion)

0.125–0.5 mg PO at bedtime

*Onset of action and duration are important in selecting the correct drug for a particular use.