Quinuclium Bromide Anhydrous is quinuclidinium derivative with potential analgesic activity. In preclinical studies, Quinuclium possessed significant chronic antihypertensive activity in mecamylamine- and renal-hypertensive dogs. Quinuclium was approximately 4 times more potent than guanethidine in the former model and 3 times as potent in the latter. Quinuclium reduced orthostatic blood pressure responses in unanesthetized rabbits but was approximately 10 times less potent than guanethidine. Quinuclium did not affect cardiac output, heart rate or stroke volume in anesthetized open-chest dogs and moderately increased mean blood pressure and total peripheral resistance. It produced diuresis and saluresis in anesthetized dogs but did not influence water or electrolyte urinary excretion in conscious rats. Quinuclium was more effective than guanethidine in blocking adrenergic neurons and depleting heart norepinephrine levels in experimental animals.