What are the side effects of hydralazine (apresoline)?

Hydralazine Side Effects

Hydralazine is associated with several significant side effects, including reflex tachycardia, sodium and water retention, headache, flushing, vomiting, and most notably, drug-induced lupus-like syndrome at higher doses (>100mg daily). 1, 2

Common Side Effects

• Cardiovascular effects:

  • Reflex tachycardia 1
  • Postural hypotension 2
  • Anginal attacks and ECG changes of myocardial ischemia 2
  • Potential increase in pulmonary artery pressure in patients with mitral valve disease 2

• Gastrointestinal effects:

  • Nausea/vomiting 1
  • Gastrointestinal complaints 3

• Neurological effects:

  • Headache 1, 3
  • Peripheral neuritis (paresthesia, numbness, tingling) 2
  • Dizziness 1

• Fluid-related effects:

  • Sodium and water retention 1

Serious Side Effects

• Autoimmune reactions:

  • Drug-induced lupus-like syndrome (particularly at doses >100mg daily) 1, 2, 4
  • ANCA-associated vasculitis 4
  • Positive antinuclear antibody titers 2

• Hematologic effects:

  • Blood dyscrasias (reduced hemoglobin, leukopenia, agranulocytosis, purpura) 2
  • Hemolytic anemia 5

• Renal effects:

  • Glomerulonephritis 5
  • May affect renal blood flow 2

• Pulmonary effects:

  • Diffuse alveolar hemorrhage 4
  • Hemoptysis 4

• Dermatologic effects:

  • Skin rash 4

Risk Factors and Monitoring

• Dose-related risks:

  • Drug-induced lupus-like syndrome risk increases significantly at doses >100mg daily 1
  • Long-term use at higher doses requires careful monitoring 1

• Recommended monitoring:

  • Complete blood counts and antinuclear antibody titer determinations before and periodically during prolonged therapy 2
  • Blood pressure monitoring after each dose increase 1
  • Monitoring for symptoms of peripheral neuritis (may require pyridoxine supplementation) 2

• High-risk populations:

  • Patients with suspected coronary artery disease (risk of myocardial ischemia) 2
  • Patients with cerebrovascular disease 2
  • Patients with advanced renal damage 2
  • Patients with mitral valvular disease 2

Drug Interactions

• Use with caution with:
  • MAO inhibitors 2
  • Other potent antihypertensive drugs (risk of excessive hypotension) 2
  • Diazoxide (risk of profound hypotension) 2

Practical Considerations

• Food increases plasma levels of hydralazine 2
• Combination with beta-blockers and diuretics is recommended to counteract reflex tachycardia and fluid retention 1
• When used for heart failure, hydralazine is typically combined with isosorbide dinitrate 1, 3

When prescribing hydralazine, clinicians should be vigilant about monitoring for these side effects, particularly autoimmune phenomena in patients on higher doses or long-term therapy. Early recognition of symptoms and appropriate dose adjustment or discontinuation can prevent progression to more serious adverse effects.