Hydralazine mechanism of action?

How does hydralazine work in the body?

Hydralazine is a direct-acting vasodilator. Its main effect is on small arteries: it relaxes vascular smooth muscle, which lowers systemic vascular resistance and reduces blood pressure [1].

What is the mechanism at the cellular level?

Hydralazine’s vasodilator action is closely linked to increased availability of nitric oxide (NO)–related signaling in the vascular endothelium and smooth muscle. This shifts the balance toward vasodilation, which helps explain its antihypertensive effect [1].

Why does hydralazine lower blood pressure (and not heart rate in the same way as some drugs)?

By primarily dilating arterioles, hydralazine reduces afterload. The body may respond with reflex sympathetic activation (for example, via increased heart rate) depending on the patient and context, but the drug’s direct pharmacologic action is on vessel tone rather than directly blocking adrenergic receptors [1].

What does hydralazine treat clinically because of this MOA?

Because it causes arteriolar vasodilation, hydralazine is used to treat high blood pressure and is sometimes used in conditions where rapid blood pressure reduction is needed under medical supervision. Its vascular effect is what drives these uses [1].

Sources

[1] https://go.drugbank.com/drugs/DB01110