Bioavailability of trospium chloride after intravesical instillation in patients with neurogenic lower urinary tract...

Oral drug treatment of detrusor overactivity often causes undesirable side effects in other organs. For some patients, in particular those with neurogenically induced detrusor overactivity (detrusor hyperreflexia), the tolerance level for adverse effects is low and oral treatment may become ineffective. Intravesical administration of the drug can diminish the side effects or increase treatment effectivity in patients who are (partially) refractory to oral treatment because the relative concentration of the drug is increased in the target organ and decreased in the circulation. Six men (19-34 years old) with traumatic spinal cord lesions between C2 and Th11 were randomized to intravesical instillation with 15 or 30 mg trospium chloride in 40 ml saline into the empty bladder. Catheterization was postponed until at least 3 h after instillation, and fluid intake was not allowed during the first 4 h. Blood samples were taken before and 11 times after instillation; the last sample 12 h post instillation. Four positive samples were found in three patients: 0.10 ng/ml after 1 h and 0.13 ng/ml after 2(1/2) h in two patients with 15 mg, and 0.24 ng/ml after 30 min and 0.70 ng/ml after 6 h in one patient with 30 mg instilled trospium chloride. Three adverse effects were reported and were rated as probably not related to the drug. It is concluded that intravesically instilled trospium chloride is not absorbed into the circulation in significant amounts and, thus, it may be expected that this mode of administration will improve the efficacy of trospium chloride therapy by reducing the side effects. Neurourol. Urodynam. 18:447-453, 1999.