A nurse is teaching a client about diphenhydramine. The nurse should explain to the client that which of the following is an adverse effect of this medication?

Choice A reason: Bradycardia is not a common adverse effect of diphenhydramine. While anticholinergic effects may influence heart rate, bradycardia is not typically associated with this medication. Choice B reason: Hypoglycemia is unrelated to diphenhydramine’s pharmacologic profile. It does not affect insulin secretion or glucose metabolism. Choice C reason: Sedation is a well-known adverse effect of diphenhydramine due to its antihistaminic and anticholinergic properties. It crosses the blood-brain barrier and depresses the central nervous system, leading to drowsiness and impaired alertness. Choice D reason: Hypertension is not a typical side effect of diphenhydramine. In fact, it may cause hypotension in some cases due to vasodilation and sedation.