Effect of 1-alpha-acetylmethadol (LAAM) on various physiological parameters in the conscious dog

LAAM was administered intravenously to conscious dogs at doses of either 0.1, 0.3 or 1.0 mg/kg. Cardiopulmonary responses were measured prior to drug administration, 0.5 hr post-drug and hourly thereafter. All doses produced a sleep-like state which was dose-related in duration (3-14 hr). Cardiac output, heart rate, respiratory rate and minute volume were decreased below mean pre-drug control values after drug administration in the two higher dosage groups; cardiac output in both groups failed to return to pre-drug control levels. Additionally, total peripheral resistance was elevated in these dosage groups although mean arterial pressure remained stable. Arterial pCO2 increased and arterial pH decreased as respiratory rate and minute volume decreased. Depression of rectal temperature occurred only in response to the highest dose.