Does Hydralazine Cause Cough?
No, hydralazine does not cause cough as a recognized adverse effect. Cough is not listed among the documented side effects of hydralazine in major cardiovascular guidelines or clinical literature.
Documented Adverse Effects of Hydralazine
The adverse effects of hydralazine fall into two distinct categories that do not include cough:
Pharmacologic (Hemodynamic) Side Effects
These result from the drug's vasodilatory mechanism:
- Headache, flushing, and reflex tachycardia are the most common adverse effects 1, 2
- Hypotension and palpitations occur due to arterial vasodilation 1
- Nausea and gastrointestinal complaints are frequently reported 1
- Sodium and water retention necessitates concurrent diuretic use 2
Immunologic Side Effects
These are dose-dependent and more serious:
- Drug-induced lupus-like syndrome is the most significant immunologic complication, particularly at doses above 150-200 mg daily 3, 4, 5
- Peripheral neuropathy with numbness, paresthesia, and motor weakness, especially at cumulative doses above 200 mg/day 6
- Vasculitis and glomerulonephritis have been reported, even at low doses 7, 8
- Hemolytic anemia is a recognized hematologic complication 7
- Hepatotoxicity with hepatocellular injury pattern, though rare 9
Clinical Pitfall: Distinguishing from ACE Inhibitor Cough
A critical clinical consideration is that cough is a hallmark adverse effect of ACE inhibitors (ACEIs), not hydralazine. Since hydralazine is often used as an alternative in patients who cannot tolerate ACEIs 1, clinicians should not attribute cough to hydralazine if it develops during therapy. If a patient on hydralazine develops cough, investigate other causes including:
- Concurrent ACEI use (hydralazine is often combined with other antihypertensives)
- Heart failure progression (pulmonary congestion)
- Pulmonary complications unrelated to hydralazine
Monitoring Recommendations
When prescribing hydralazine, monitor for its actual adverse effects rather than cough: