Effects on tremor, akathisia and rigidity, sedative effects, may enhance other antiparkinsonian agents.

• A. Cogentin therapeutic effects
• B. Benadryl therapeutic effects
• C. Adverse effects
• D. Breast milk effects

Answer: (B)

Diphenhydramine (Benadryl) has therapeutic effects for Parkinsonian and extrapyramidal symptoms because it is a strong anticholinergic. By blocking acetylcholine in the brain, it helps rebalance the dopamine-acetylcholine system in the basal ganglia, reducing tremor and rigidity and easing drug-induced akathisia. Its antihistamine action also causes sedation, which can calm restlessness and discomfort associated with EPS. In practice, this sedative, anticholinergic profile can be used together with other antiparkinsonian agents to improve overall motor control, sometimes allowing lower doses of dopaminergic therapies. Keep in mind the anticholinergic effects, which can be problematic in older patients (dry mouth, urinary retention, confusion, delirium).