From the Guidelines
Hydralazine does not typically cause hyponatremia (low sodium levels in the blood). Hydralazine is a direct-acting vasodilator primarily used to treat hypertension and heart failure. Its main side effects include headache, tachycardia, palpitations, flushing, dizziness, and a lupus-like syndrome with long-term use. According to the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1, hydralazine is associated with sodium and water retention and reflex tachycardia, but it does not commonly cause hyponatremia.
Key Points to Consider
- Hydralazine is associated with sodium and water retention, which can lead to edema, but it is not typically associated with hyponatremia.
- The guideline recommends using hydralazine with a diuretic and beta blocker to minimize its side effects 1.
- Other medications, such as thiazide diuretics, selective serotonin reuptake inhibitors (SSRIs), carbamazepine, and certain antipsychotics, are more commonly associated with hyponatremia.
- If a patient taking hydralazine develops hyponatremia, clinicians should consider other causes or concomitant medications rather than attributing it to hydralazine.
Recommendations for Clinical Practice
- Patients with unexplained hyponatremia while on hydralazine should undergo evaluation for other potential causes, including other medications, syndrome of inappropriate antidiuretic hormone secretion (SIADH), heart failure, liver disease, or kidney problems.
- Clinicians should carefully monitor patients taking hydralazine for signs of sodium and water retention, such as edema, and adjust the treatment plan as needed.
- The use of hydralazine should be individualized, and patients should be closely monitored for potential side effects, including lupus-like syndrome, which can occur at higher doses 1.
From the Research
Hydralazine and Hyponatremia
- There is limited direct evidence on the relationship between hydralazine and hyponatremia from the provided studies 2, 3, 4, 5.
- One study from 1984 6 investigated the effects of various vasodilator and inotropic therapies, including hydralazine, on hyponatremia in patients with severe heart failure.
- The study found that serum sodium concentration increased only in hyponatremic patients treated with captopril, but not in those treated with hydralazine or other agents 6.
- This suggests that hydralazine may not have a significant effect on correcting hyponatremia in patients with severe heart failure, unlike captopril which appears to have a corrective effect on hyponatremia through its action on the renin-angiotensin system 6.
- The other studies provided do not directly address the relationship between hydralazine and hyponatremia, focusing instead on the drug's antihypertensive effects, dose-response curve analysis, and potential antioxidant properties 2, 3, 4, 5.