Hydralazine

How it works

It relaxes arteriolar smooth muscle directly, reducing systemic vascular resistance and arterial blood pressure.

Prescribing in practice

• Long-term or higher-dose use can cause a drug-induced lupus-like syndrome, which should prompt review and discontinuation.
• Reflex tachycardia and fluid retention often require co-administration of a beta-blocker and a diuretic.
• In heart failure it is combined with a nitrate, particularly where renin-angiotensin system inhibitors are unsuitable.

Monitoring

Monitor blood pressure and heart rate, and remain alert for features of a lupus-like syndrome such as arthralgia and rash.

Counselling the patient

• This medicine lowers blood pressure by relaxing the blood vessels.
• Report persistent joint pains, fever, rash or unusual tiredness.
• Do not stop the medicine suddenly without advice.

Evidence & guidelines

The combination of hydralazine with isosorbide dinitrate improved outcomes in heart failure trials, including benefit demonstrated in self-identified Black patients in the A-HeFT trial.