Atropine-like side effects such as dry mouth; blurred vision; drowsiness; euphoria or disorientation; urinary retention; postural hypotension; constipation; agitation; disturbed behavior may been seen. A case of generalized choreic movements has been reported in a Parkinson's disease patient when biperiden was added to carbidopa/levodopa. A reduction in rapid eye movement (REM) sleep, characterized by increased REM latency and decreased percentage of REM sleep, has been reported. There usually are no significant changes in blood pressure or heart rate in patients who have been given the parenteral form of AKINETON (biperiden) . Mild transient postural hypotension and bradycardia may occur. These side effects can be minimized or avoided by slow intravenous administration. No local tissue reactions have been reported following intramuscular injection. If gastric irritation occurs following oral administration, it can be avoided by administering the drug during or after meals.
The central anticholinergic syndrome can occur as an adverse reaction to properly prescribed anticholinergic medication. See OVERDOSAGE section for signs and symptoms of the central anticholinergic syndrome, and for treatment.