Drug Groups

approved

Description

A butyrophenone with general properties similar to those of haloperidol. It is used in conjunction with an opioid analgesic such as fentanyl to maintain the patient in a calm state of neuroleptanalgesia with indifference to surroundings but still able to cooperate with the surgeon. It is also used as a premedicant, as an antiemetic, and for the control of agitation in acute psychoses. (From Martindale, The Extra Pharmacopoeia, 29th ed, p593)

Indication

Droperidol is ssed to produce tranquilization and to reduce the incidence of nausea and vomiting in surgical and diagnostic procedures.

Pharmacology

Droperidol produces marked tranquilization and sedation. It allays apprehension and provides a state of mental detachment and indifference while maintaining a state of reflex alertness. Droperidol produces an antiemetic effect as evidenced by the antagonism of apomorphine in dogs. It lowers the incidence of nausea and vomiting during surgical procedures and provides antiemetic protection in the postoperative period. Droperidol potentiates other CNS depressants. It produces mild alpha-adrenergic blockade, peripheral vascular dilatation and reduction of the pressor effect of epinephrine. It can produce hypotension and decreased peripheral vascular resistance and may decrease pulmonary arterial pressure (particularly if it is abnormally high). It may reduce the incidence of epinephrine-induced arrhythmias, but it does not prevent other cardiac arrhythmias.

Toxicity

The intravenous LD₅₀ of droperidol is 20-43 mg/kg in mice; 30 mg/kg in rats; 25 mg/kg in dogs and 11-13 mg/kg in rabbits. The intramuscular LD₅₀ of droperidol is 195 mg/kg in mice, 104-110 mg/kg in rats; 97 mg/kg in rabbits and 200 mg/kg in guinea pigs. The manifestations of droperidol overdosage are an extension of its pharmacologic actions.

Affected Organisms

Biotransformation

Extensively metabolized.

Absorption

Completely absorbed following intramuscular administration.

Half Life

Biphasic distribution. The rapid distribution phase is 1.4 ± 0.5 minutes and the slower distribution phase is 14.3 ± 6.5 minutes. Elimination half-life in adults is 134 ± 13 minutes and may be increased in geriatric patients. In children, it is 101.5 ± 26.4 minutes.

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