, ▁or ▁narrow ing ▁of ▁the ▁u re th ra ), ▁or ▁when ▁the ▁mus cle ▁that ▁exp els ▁ur ine ▁from ▁the ▁bl ad der ▁is ▁too ▁weak ▁to ▁empty ▁the ▁bl ad der ▁normally . ▁Overflow ▁in cont in ence ▁may ▁also ▁be ▁a ▁side ▁effect ▁of ▁certain ▁medic ations . ▁ ▁C aus es ▁Les ions ▁affect ing ▁sac ral ▁segments ▁or ▁peri pher al ▁autonom ic ▁fib res ▁result ▁in ▁at onic ▁bl ad der ▁with ▁loss ▁of ▁s ph inct er ic ▁coord ination . ▁This ▁results ▁in ▁loss ▁of ▁det rus or ▁contra ction , ▁difficulty ▁in ▁initi ating ▁m ict ur ition ▁and ▁overflow ▁in cont in ence . ▁Ant ich ol iner g ic ▁side ▁effects ▁of ▁certain ▁medic ations ▁( for ▁example , ▁certain ▁anti ps ych ot ics ▁and ▁ant ide press ants ) ▁may ▁cause ▁ur inary ▁ret ention ▁which ▁may ▁lead ▁to ▁overflow ▁in cont in ence . ▁Al pha - adr ener g ic ▁ag on ists ▁may ▁cause ▁ur inary ▁ret ention ▁by ▁stim ulating ▁the ▁contra ction ▁of ▁the ▁u re th ral ▁s ph inct er . ▁Cal ci um ▁channel ▁block ers ▁may ▁decrease ▁the ▁contract ility ▁of ▁the ▁smooth ▁mus cle ▁t issue ▁in ▁the ▁ur inary ▁bl ad der , ▁causing ▁ur inary ▁ret ention ▁with ▁overflow ▁in cont in ence . ▁E pid ural ▁an est hes ia ▁and ▁delivery ▁also ▁can ▁cause ▁the ▁overflow ▁in cont in ence . ▁ ▁Path oph