Mechanism:
It Liberates nitric oxide (NO) → ↑ cGMP → ↓ Ca2+ entry in the vascular sm ms → dilatation of both arteries and veins.
Therapeutic uses:
-
Hypertensive Emergency; encephalopathy: It must be given by i.v. infusion .
-
Congestive heart failure: to ↓ both preload (venodilatation) and afterload (arteriolodilatation).
Side effects:
- Hypotension and reflex tachycardia.
- Headache, Anginal pain, Nausea, Dizziness (HAND).
- Prolonged therapy can lead to cyanide toxicity.
Precautions:
- Avoid exposure to light because the drug is sensitive to light.
- Stop infusion gradually to avoid rebound hypertension.
- Too much infusion may lead to cyanide toxicity.