Pancuronium Bromide (Pavulon). Evaluation of Its Clinical Pharmacology

Abstract

PANCURONIUM BROMIDE IS AN amino steroid muscle relaxant (Figure 1) which was synthesized in 1964 by Hewett and Savage and has been studied and evaluated clinically in Europe during the past four years2 -5 It is an odourless, white, crystalline powder with a bitter astringent taste, melts at 215~ with decomposition, and is soluble in 50 parts of chloroform and one part water at 20~ The co]ourless solution is stable while sealed, but breaks down in a few hours after exposure to air. In Europe it is available in 2-ml ampoules containing 4 mg pancuronium bromide, 18 nag sodium chloride B.P. and water for injection B.P. to 2 mls. The preparation which was used in this study contains preservatives (acetic acid and sodium acetate) to buffer the solution to pH 4.0. Pharmacological studies have shown that it has no hormonal action but is a potent non-depolarizing skeletal muscle relaxant like'tubocurarine and gallamine. It has a more rapid onset of action than tubocurarine with a similar duration of action. It has a somewhat longer action than gallamine. It has no significant effect on the blood pressure or the tracheobronchial tree due to the very. slight ganglionblocking action and the claim is that no histamine is released, a It does not affect OOC. CH

Pancuronium Bromide

“…The sequence of muscle paralysis began with the eye, followed by the pharyngeal and laryngeal muscles, the intercostals and lastly the diaphragm. Dobkin et al (1971) found that the duration of action of pancuronium varied considerably with the anaesthetic technique employed, but lasted at least 90 minutes in an average sized fit adult when doses of 0.1 mg/kg were given with a sleep dose of thiopentone (4 to 5 mg/kg) and a halogenated anaesthetic. Similarly, with initial doses of 0.06 to 0.07 mg/kg, Iwatsuki et al (1970) found that apnoea developed within 30 to 150 seconds (mean 80 seconds), whilst the duration of action varied from 40 to 60 minutes.…”

“…In 465 patients undergoing a variety of surgical procedures, Dobkin et al (1971) reported good operating conditions in approximately 90 % or more of the patients with each anaesthetic technique used (see table II). Among the 4 groups of patients studied (each of which represents a different technique of administering muscle relaxant drugs -see table I), the technique employed in group B had the most cases in which the relaxation was not considered good (18 %).…”

“…In patients anaesthetised with a combination of 4 to 5 mg/kg thiopentone and 0.1 mg/kg pancuronium, Dobkin et al (1971) found that the jaw and larynx were not fully relaxed until the patients were unconscious, and at least 150 seconds had elapsed after the administration of pancuronium (mean time to intubation 2 minutes 18 seconds). Intubation was described as good in 218 patients (i.e.…”

“…In a number of studies, intubating conditions with pancuronium were found to be inferior to those provided by suxamethonium (Baird, 1968;Bronner, 1970;Dobkin et al, 1971;Sellick, 1968Sellick, , 1970Stojanov, 1969;Szappanyos et al, 1969). Baird (1968), after noting that the first 25 of his 115 patients invariably gave a slight cough when intubated with pancuronium, subsequently used suxamethonium for rapid intubation followed by pancuronium for the remainder of the operation.…”

“…Sellick (1970) noted that when this procedure was used, full abdominal relaxation was obtained with approximately half the dose of pancuronium normally required for intubation. Similarly, in patients intubated with 1.5 mg/kg suxamethonium or with 2.2 mg/kg suxamethonium preceded by 6 mg d-tubocurarine (to avoid fasciculation), Dobkin et al (1971) found that the dose requirement of pancuronium (in mg/kg/minute of surgery), was reduced by approximately 20 to 30 % when compared with patients intubated with 0.1 mg/kg pancuronium alone (see table I and also section 2.12.2). Whereas the latter usually received initial doses of 4 to 8 mg pancuronium, the patients who received 1.5 mg/kg suxamethonium first were usually given doses of 3 to 6 mg (depending on the size and physique of the patient) as the action of suxamethonium was wearing off, followed by increments of 1 to 2 mg as necessary.…”