Antimuscarinic and noncompetitive antagonist properties of dicyclomine hydrochloride in isolated human and rabbit bladder muscle

In isolated strips of bladder neck (prostatic capsule) and detrusor of rabbit and man, dicyclomine had minimal effect on the resting tension. Competitive antimuscarinic activity against carbachol could be demonstrated at doses of dicyclomine less than or equal to 1 x 10^-6 M, whereas at higher doses a noncompetitive action against both carbachol and potassium was observed. The ratio of dissociation constants relating to the noncompetitive and competitive actions, respectively, was about 1200, approximately 100 times higher than that previously reported in ileum. Dicyclomine was only about 1/30 as potent as atropine in competitive antimuscarinic activity. Dicyclomine hydrochloride may be useful in the clinical management of 'uninhibited bladder'.