Editing Functional: Pharmacological Management of LUTS (section)

====== Oxybutynin (Ditropan) ======
* '''Mechanism of action:'''
*# '''Blocks muscarinic receptors''' (main effect when given systemically)
*# '''Direct muscle relaxant'''
*# '''Local anesthetic effects'''
*#* The latter 2 may be of importance when the drug is administered intravesically, but probably play no role when it is given orally.
* '''Metabolism: Undergoes extensive upper gastrointestinal and first-pass hepatic metabolism via the cytochrome P450 system (CYP3A4) into multiple metabolites.'''
** '''The primary metabolite, N-desethyloxybutynin, has been implicated as the major cause of the troublesome side effect of dry mouth associated with oxybutynin.'''
* Selectivity: slightly higher affinity for M1 and M3 receptors than for M2 receptors
* Dosing: Immediate release and extended release formulations available, as well as a transdermal patch and gel formulations.
** '''Transdermal delivery''' also alters oxybutynin metabolism, reducing N-desethyloxybutynin production to an even greater extent than OXY-ER, and is associated with '''much less dry mouth. Side effects include application site reaction pruritus and erythema'''
* '''Adverse events:'''
** '''Immediate release has high incidence of side effects (dry mouth, constipation, drowsiness, blurred vision)'''
** Extended release version was developed to decrease liver metabolite formulation of N-desethyloxybutynin with the presumption that it would result in decreased side effects
** A significant dose-response relationship for both urgency incontinence episodes and dry mouth.
** '''Studies show no effect on ECG'''
** '''May have negative effects on cognitive function, particularly in the elderly population but also in children'''
*Estimated cost per month: 10$ USD[https://www.goodrx.com/]