INHIBITORY EFFECT OF KETOTIFEN ON CONTRACTIONS OF RAT ISOLATED BLADDER

Ketotifen is a benzocycloheptathiophene with a range of pharmacological activities. The present study was carried out to evaluate the action of ketotifen on isolated rat bladder contractions induced by KCI and acetylcholine, compared with the effects of other drugs. Ketotifen (5 µM) reduced the response to acetylcholine on rat isolated bladder without altering the maximum response and shifted the acetylcholine concentration-response curve to the right 16 - fold. Ketotifen also reduced the KCl response, while atropine only inhibited the response to acetylcholine. Diazoxide inhibited bladder - induced contraction only at high concentration (500 µM). This study shows that ketotifen is a relaxant of isolated rat bladder. As the inhibition of contractile overactivity of the bladder is the basis of treatment of bladder instability, provided that a similar effect will be seen in vivo, then ketotifen may have clinical benefits for treatment of this condition.