Racial differences and mydriatic response to tyramine

SummaryIn a preliminary study the effect of tyramine, used as eye-drops, was assessed in two different ethnical groups composed of healthy volunteers: 6 Africans and 6 Caucasians.Tyramine-induced mydriasis in the Caucasian group was 5 times greater than in the African group.Similar differences had already been observed for indirect sympathominetic amines (ephedrine and cocaine) used as mydriatics, as well as for the effects of alpha 1 blocking drugs on the vascular system.Very few data are available in the literature concerning the CNS effects of drugs modulating the alpha adrenergic receptors.