Pediatric Drug Interactions with Diphenhydramine

• CNS depressants (benzodiazepines, opioids): additive sedation/respiratory depression
• Alcohol: increased drowsiness—avoid
• MAO inhibitors: contraindicated due to severe interactions
• Other anticholinergics: additive dry mouth, blurry vision, urinary retention
• Cough/cold combinations: avoid routine use in young children