A nurse is collecting data from a client who is taking dimenhydrinate to treat motion sickness. Which of the following findings is an adverse effect of this medication?

Choice A rationale Hypertension, or elevated blood pressure, is not a common adverse effect of dimenhydrinate. Dimenhydrinate is an antihistamine with anticholinergic properties; while some anticholinergics can cause tachycardia, they typically do not lead to significant hypertension. Blood pressure should be within normal limits, e.g., 120/80 mmHg. Choice B rationale Polyuria, the excessive production of urine, is not a recognized adverse effect of dimenhydrinate. Anticholinergic medications like dimenhydrinate can sometimes cause urinary retention due to relaxation of the detrusor muscle, rather than increased urine output. Normal urine output is approximately 0.5-1 mL/kg/hour. Choice C rationale Drowsiness is a very common and expected adverse effect of dimenhydrinate. As an H1 receptor antagonist, it readily crosses the blood-brain barrier and exerts central nervous system depression, leading to sedation and somnolence. This effect is often utilized for its antiemetic properties. Choice D rationale Dependent edema, the accumulation of fluid in dependent body parts, is not an adverse effect associated with dimenhydrinate. This symptom is typically linked to cardiovascular issues like heart failure or venous insufficiency, not to the pharmacological actions of antihistamines.