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Direct Vasodilator·Cardiovascular - Vasodilators
Moderate-to-severe hypertension, pre-eclampsia, HFrEF (in combination with nitrates)
Max Dose
200 mg/day
Half-life
1-2 h
Lupus-like
RARE
Tachycardia
REFLEX
Overview
Direct-acting smooth muscle relaxant acting purely on arterioles. Powerful but triggers a massive reflex sympathetic response (tachycardia).
Maximum Dose
Max 200 mg/day (to avoid autoimmune lupus-like syndrome).
Clinical Focus
Almost never used as monotherapy; must be paired with a beta-blocker to prevent reflex tachycardia and a diuretic to prevent fluid retention.
Bottom Line
Hydralazine is a direct vasodilator safe in pregnancy and useful in heart failure (with nitrate), but causes reflex tachycardia and can trigger drug-induced lupus with chronic use.
Brand Names
Apresoline
Oral Routes
Tablets (25 mg, 50 mg).
Parenteral
Ampoule (20 mg powder for reconstitution).
Prescribing & PBS
Unrestricted General Benefit (S4).
Primary
Moderate-to-severe hypertension, pre-eclampsia, HFrEF (in combination with nitrates).
Clinical Place
Third or fourth-line agent for resistant hypertension. Major role in severe pre-eclampsia.