Diphenhydramine (Benadryl) Pharmacology

Diphenhydramine is a first generation antihistamine that is highly anticholinergic. When using medications like diphenhydramine, be sure to watch for side effects like dry eyes, dry mouth, constipation, urinary retention, and CNS changes. Sedation is a primary effect of diphenhydramine. It can be advantageous in certain situations, and detrimental in others. Drugs like donepezil, memantine, laxatives, tamsulosin, and artificial tears can be indicators of anticholinergic side effects from diphenhydramine. I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care. Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!