A nurse is administering medications to a client and mistakenly gives hydroxyzine instead of hydralazine. For which of the following adverse effects should the nurse monitor the client?

Hydroxyzine is a first-generation antihistamine that crosses the blood-brain barrier, leading to significant anticholinergic and sedative effects. In contrast, hydralazine is a peripheral vasodilator used for hypertension. This look-alike, sound-alike error involves switching a sedative for an antihypertensive, requiring close neurological and cardiovascular monitoring. Rationale: A. Sedation is a primary adverse effect of hydroxyzine due to its ability to block H1 receptors in the central nervous system. Because the client received this instead of a blood pressure medication, the nurse must monitor for extreme drowsiness, dizziness, and a possible risk for falls. Sedation is the most immediate and expected neurological consequence of this specific medication error. B. Drooling is not associated with hydroxyzine; rather, this medication has anticholinergic properties that typically cause dry mouth (xerostomia). Hydroxyzine reduces secretions and blocks parasympathetic activity, making drooling an unlikely finding. If the client experiences drooling, the nurse should investigate other causes, such as neurological impairment or the effect of different pharmacological agents. C. Diarrhea is not a common side effect of hydroxyzine administration. Antihistamines with anticholinergic effects are more likely to cause constipation due to slowed gastrointestinal motility. The nurse should monitor for decreased bowel sounds rather than increased frequency of stools. Diarrhea would be an atypical response to the mistaken administration of an antihistamine. D. While hydralazine (the intended drug) treats hypertension, the nurse should monitor for high blood pressure because the client missed their antihypertensive dose. However, the prompt asks for the adverse effect of the medication actually given. Hydroxyzine itself does not cause hypertension; instead, the primary risk of the drug actually administered is central nervous system depression and potential hypotension.