Which anti-hypertensive medication is associated with a lupus-like syndrome?

Hydralazine is recognized for its association with a lupus-like syndrome, a unique adverse effect that involves a reversible, autoimmune reaction mimicking systemic lupus erythematosus (SLE). This reaction is particularly noteworthy because it arises after prolonged use or at higher doses. Patients may develop symptoms such as joint pain, fever, and skin rashes, which can lead to a misdiagnosis of lupus if not appropriately identified. The mechanism believed to underpin this side effect involves the formation of antinuclear antibodies, which can trigger an autoimmune response in susceptible individuals.

The other medications listed do not have a significant association with this particular syndrome. Labetalol is a mixed α/β blocker typically used in hypertension and does not demonstrate similar autoimmune reactions. Nicardipine, a calcium channel blocker, is primarily utilized for managing hypertension and does not possess the qualities that induce lupus-like symptoms. Nitroprusside, used for acute hypertensive emergencies, can lead to cyanide toxicity but is also not linked to lupus-like reactions. Therefore, hydralazine stands out as the only anti-hypertensive medication among the options provided that is classically associated with a lupus-like syndrome.