Medications Under Development for the Overactive Bladder
Duloxetine is a 5-HT3 and norepinephrine reuptake inhibitor. This is an experimental class of agents that appear to have little effect on the normal bladder. However, in animal studies of chemically irritated bladders, there appears to be a reduced overactivity of the bladder based on possible 5-HT2 receptor and a1-adrenergic mechanisms.
Desmopressin is used in children with nocturnal enuresis, and it has recently shown some promise in the treatment of OAB in adults. Desmopressin is a synthetic analogue of vasopressin and thus acts as an antidiuretic. Although desmopressin at bedtime does not "cure" OAB, it can effectively decrease urine output for approximately 6 hours; this allows the patient to sleep with fewer disruptive trips to the bathroom.
Desmopressin administration does have risks. Fluid overload and hyponatremia may result from excessive fluid intake. Severe hyponatremia may induce seizures and coma. Serum electrolyte monitoring is a reasonable precaution with initiation of this medication. Patients with electrolyte or fluid balance abnormalities, such as congestive heart failure and cystic fibrosis, should be monitored carefully or should not be given this medication at all.
Potassium channel openers, such as cromakalin and levcromakalin, relax smooth muscle by allowing an efflux of potassium. The efflux of potassium results in membrane hyperpolarization and subsequent smooth muscle relaxation. At present, the lack of clinical efficacy and the significant side effect profile limit the enthusiasm for this regimen.[41,42] Several drug companies are developing bladder-selective potassium channel openers without adverse effects on the heart or vascular system. These agents are in preliminary developmental stages and may prove an exciting alternative in the future.
© 2000 Cliggott Publishing, Division of CMP Healthcare Media
Cite this: New Pharmacologic and Minimally Invasive Therapies for the Overactive Bladder - Medscape - May 01, 2000.