FIELD : medicine.SUBSTANCE : group of inventions relates to medicine, specifically urology, and can be used to treat bladder dysfunction. Disclosed is a medicament comprising trospium for local administration into the bladder of a patient to achieve a sustained concentration of trospium in urine in the bladder sufficient to produce a therapeutic concentration of trospium in bladder tissue with an average dosage of trospium from 0.075?mg/day to 150?mg/day during the treatment period lasting from 1 to 180 days with a sustained concentration of trospium in urine in the bladder from 0.05?mcg/ml to 100?mcg/ml continuously during the treatment period. Method for administering trospium to a patient and a medical device for delivering a medicament are also provided.EFFECT : group of inventions improves the effectiveness of treatment by providing a sustained therapeutically effective concentration of trospium in the bladder, with active effect on both detrusor activity and the sensory function of the urothelium.26 cl, 18 dwg, 3 tbl, 3 ex