ALFETAMINE (aletamine) is an antidepressant and analgesic. The pharmacologic activity profile of aletamine closely resembles that of the tricyclic antidepressants imipramine and amitriptyline. Effects shared are antagonism of RO4-1284-induced ptosis and depressed exploratory behavior, depression of spontaneous motor activity, prolongation of hexobarbital hypnosis and anticonvulsant action in mice, hypotension and potentiation of norepinephrine pressor effects in dogs, antimuricidal effects, hypothermia in rats and local anesthesia in rabbits and guinea pigs. Aletamine differed from imipramine and amitriptyline as follows: (1) aletamine exerted no apparent central or peripheral anticholinergic effect as suggested by lack of influence on tremorine-induced tremors or salivation; (2) although aletamine was less potent on a milligram basis than imipramine and amitriptyline in preventing RO4-1284 depression, aletamine was more potent than imipramine in counteracting existing reserpine depression (ptosis, depressed exploratory behavior) in mice. Amitriptyline was inactive against reserpine depression. The pharmacologic effects of aletamine differ in several respects from those of d-amphetamine. The effects of aletamine on spontaneous motor activity, hexobarbital hypnosis and body temperature in rodents and on blood pressure in dogs are in opposite direction to those of amphetamine. In further contrast to amphetamine, grouping of mice has no influence on the toxicity of aletamine. Aletamine does not appear to be an inhibitor of monoamine oxidase in vivo since it does not enhance tryptamine-induced convulsions in rats.