Adrenergic release inhibitors are a class of drugs which inhibit the release ofepinephrine (adrenaline) and/ornorepinephrine (noradrenaline) fromadrenergicnerve terminals and are used asantihypertensives.[1][2] Examples of these agents includebethanidine,bretylium,debrisoquine,guanisoquin(7-bromo Debrisoquine),guanadrel,guanazodine,guancydine,guanethidine,guanoclor, andguanoxan.[1][2] Most agents of this class areguanidinium compounds and have little capacity to cross theblood–brain barrier.[2]