Drug-Induced Urinary Retention Drug-induced urinary retention is very common and can be caused by many classes of medication. It may occur more often in men due to concurrent prostate hypertrophy, but should be considered in women as well. Micturition occurs via: 1. Detrusor muscle contraction due to acetylcholine (ACh), which binds the type-3 muscarinic receptor (M3). 2. Internal urethral sphincter relaxation due to decreased sympathetic input to both α1 and β3 receptors. 3. External urethral sphincter relaxation via decreased ACh-mediated activity of Nicotinic (N) receptors 4. Localized prostaglandin signaling Drug Classes Causing Urinary Retention: • Anticholinergic drugs • Opioids • Alpha & Beta Receptor Agonists • GABA-ergic drugs • NSAIDs • Calcium channel blockers • SSRI/SNRI drugs By Dr. Kathryn Watson @Kat_Watson #Urinary #Retention #Drug #Induced #differential #diagnosis #pharmacology
