A nurse is caring for a client who has developed agranulocytosis as a result of taking propylthiouracil to treat hyperthyroidism. The nurse should understand that this client is at increased risk for which of the following conditions?

Choice A reason: Bradycardia is not an adverse effect of diphenhydramine. Bradycardia is a slow heart rate, usually below 60 beats per minute. Diphenhydramine is an antihistamine that blocks the effects of histamine, a chemical that causes allergic reactions. Diphenhydramine does not affect the heart rate, although it may cause palpitations or irregular heartbeat in some cases.

Choice B reason: Constipation is an adverse effect of diphenhydramine. Constipation is a condition in which the bowel movements are infrequent, hard, or difficult to pass. Diphenhydramine has anticholinergic properties, which means it inhibits the activity of acetylcholine, a neurotransmitter that regulates the smooth muscle contraction in the gastrointestinal tract. Diphenhydramine can reduce the intestinal motility and cause constipation, as well as dry mouth, blurred vision, and urinary retention.

Choice C reason: Hypertension is not an adverse effect of diphenhydramine. Hypertension is a condition in which the blood pressure is abnormally high, usually above 140/90 mmHg. Diphenhydramine does not affect the blood pressure, although it may cause orthostatic hypotension, which is a sudden drop in blood pressure when changing positions from lying to standing. This can cause dizziness, fainting, or falls.

Choice D reason: Sedation is an adverse effect of diphenhydramine. Sedation is a state of reduced alertness, awareness, or responsiveness. Diphenhydramine can cross the blood-brain barrier and affect the central nervous system, causing drowsiness, fatigue, impaired coordination, and reduced mental performance. Diphenhydramine can also potentiate the effects of alcohol and other sedatives, such as benzodiazepines, opioids, or barbiturates. The nurse should advise the client to avoid driving, operating machinery, or performing other tasks that require attention and concentration while taking diphenhydramine.

Choice A reason: Ototoxicity is not a severe reaction to propranolol, but it may occur with some other medications, such as aminoglycosides, loop diuretics, or salicylates. Ototoxicity may damage the inner ear or the auditory nerve and cause hearing loss, tinnitus, or vertigo. The nurse should assess the client's medication history and monitor the client's hearing function.

Choice B reason: Hypokalemia is not a severe reaction to propranolol, but it may occur with some other medications, such as thiazide diuretics, corticosteroids, or insulin. Hypokalemia may cause muscle weakness, cramps, arrhythmias, or cardiac arrest. The nurse should advise the client to eat foods rich in potassium, such as bananas, oranges, or potatoes, and to have regular blood tests to check the electrolyte levels.

Choice C reason: Tachycardia is not a severe reaction to propranolol, but it may be a sign of overdose, withdrawal, or rebound effect. Propranolol is a beta-blocker that lowers the heart rate and blood pressure by blocking the effects of epinephrine and norepinephrine. Propranolol may cause bradycardia, not tachycardia, as a side effect. The nurse should monitor the client's vital signs and advise the client to take the medication as prescribed and not to stop it abruptly.

Choice D reason: Postural hypotension is a severe reaction to propranolol, as it may cause dizziness, fainting, or falls. Postural hypotension occurs when the blood pressure drops significantly when the client changes position, such as from lying to sitting or standing. Propranolol may cause postural hypotension by reducing the vascular tone and the cardiac output. The nurse should instruct the client to change position slowly and to report any symptoms of postural hypotension to the provider.