Cardiac effects of 1-α-acetylmethadol I. Chronotropic effects in vitro

Abstract

The drug 1-α-acetylmethadol (LAAM) is a long-acting, orally effective narcotic agonist. It has been proposed as a replacement for methadone in the medical treatment of persons addicted to narcotic analgesics. The purpose of the present investigation was to determine whether or not LAAM possesses chronotropic properties. The results reported here indicate that high concentrations of the major metabolites of the drug (1-α-acetylnormethadol, 1-α-acetyldinormethadol) as well as high concentrations of the parent compound produce significant negative chronotropic effects on isolated right atria of guinea pigs. These effects could not be blocked by the prior administration of naloxone, a narcotic antagonist. LAAM also decreases the positive chronotropic efficacy of norepinephrine.