Mechanism:
direct arteriolodilator by opening K+ channels → hyperpolarization → relaxation of the vascular sm ms.
Therapeutic uses:
-
Hypertensive emergencies e.g. hypertensive encephalopathy. (rapid i.v. injection to avoid rapid and extensive binding with plasma proteins) otherwise it will be inactive
-
Hypoglycemia due to hyperinsulinism to decrease insulin secretion from the pancreatic β-cells through opening of its K+ channels.
Side effects:
- Hypotension and reflex tachycardia.
- Salt and water retention.
- Headache, Anginal pain, Nausea, Dizziness (HAND).
- Hyperglycemia due to inhibition of insulin release.
- Hyperuricemia.