Vasodilators
Start with the big picture
Hydralazine, minoxidil, and sodium nitroprusside reduce systemic vascular resistance and afterload through distinct mechanisms: increased cGMP signaling, potassium-channel opening, or nitric oxide release. Hydralazine and minoxidil mainly dilate arterioles, while nitroprusside dilates both arteries and veins, lowering preload as well as afterload. Their uses range from acute blood-pressure control to selected cases of severe chronic hypertension, heart failure, and topical treatment of alopecia. A shared concern is reflex sympathetic activation, which can cause tachycardia and renin release. Their safety profiles differ: hydralazine may cause a lupus-like syndrome, minoxidil can cause fluid retention and hypertrichosis, and nitroprusside carries cyanide or thiocyanate toxicity risk. The deeper lesson develops administration, contraindications, monitoring, interactions, and toxicity management.
What you'll learn
- Compare the mechanisms of hydralazine, minoxidil, and sodium nitroprusside.
- Distinguish the arterial and venous effects of these vasodilators.
- Relate each agent to its listed clinical indications.
- Identify characteristic adverse effects and major safety concerns.
- Recognize the need for monitoring and toxicity precautions with nitroprusside.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
