Barbiturate and hypnosedative withdrawal by a multiple oral phenobarbital loading dose technique

Abstract

Although i.v. phenobarbital loading is effective in barbiturate withdrawal, controlled infusions of drug are inconvenient. To develop a practical and more widely applicable method, oral loading doses of phenobarbital were given to 21 human barbiturate addicts, whose estimated mean daily intake of barbiturates was 1 g (range 0.5-4 g). Twelve had a past or present history of barbiturate withdrawal seizures. Phenobarbital was given orally at a rate of 120 mg/h until a predetermined clinical end point of phenobarbital effect was achieved. This end point was the presence of at least 3 of the following: nystagmus, drowsiness, ataxia, dysarthria or emotional lability. The total phenobarbital loading dose (.hivin.x [mean] .+-. SD) was 23.4 .+-. 7.1 mg/kg, median phenobarbital concentration after loading was 35.9 mg/l (range 13.2-71.6 mg/l), and median half-life (t1/2) of penobarbital was 90 h (range 38-240 h). One patient with t1/2 = 38 h was given supplemental doses of phenobarbital. None developed seizures or other evidence of barbiturate withdrawal.