vasodilators - Sheet1 Flashcards
What are the two types of vasodilators based on selectivity?
Arteriole vasodilators (e.g., hydralazine) and venous vasodilators (e.g., nitroglycerin).
What effect do arteriole vasodilators have on the heart?
Decrease cardiac afterload → Less cardiac work → Increased cardiac output → Increased tissue perfusion.
What effect do venous vasodilators have on the heart?
Decrease cardiac preload → Less cardiac work → Decreased cardiac output → Decreased tissue perfusion.
Name a vasodilator that affects both arterioles and veins.
Prazosin.
What are the main uses of vasodilators?
HTN, hypertensive crisis, angina pectoris, heart failure, MI, pheochromocytoma, peripheral vascular disease (PVD), pulmonary arterial HTN, controlled hypotension in surgery.
What medications may be needed to counteract vasodilator adverse effects?
Beta blockers and diuretics.
What are the three main adverse effects of vasodilators?
Postural hypotension (venous only), reflex tachycardia, expansion of blood volume.
What type of vasodilator is Hydralazine?
Arteriole dilator
Does hydralazine cause postural hypotension?
No, because it only dilates arterioles.
What are the effects of arteriole dilation from hydralazine?
↓ Cardiac afterload → Less cardiac work → ↑ Cardiac output → ↑ Tissue perfusion.
What are the adverse effects of hydralazine?
HA, dizziness, weakness, fatigue, SLE-like syndrome, reflex tachycardia, increased blood volume.
What is hydralazine often combined with to counteract side effects?
Beta-blockers (for reflex tachycardia) & diuretics (for fluid retention).
What type of vasodilator is Minoxidil?
Arteriole dilator
What unique adverse effect is associated with minoxidil?
Hypertrichosis (excessive hair growth).
What are other adverse effects of minoxidil?
Pericardial effusion, nausea, HA, fatigue, breast tenderness, glucose intolerance, thrombocytopenia, skin reactions, reflex tachycardia, increased blood volume.
What is minoxidil often combined with?
Beta-blockers & diuretics.
What type of vasodilator is Sodium Nitroprusside?
Dilates both veins & arterioles.
What is sodium nitroprusside primarily used for?
Hypertensive crisis (fastest-acting antihypertensive).
How is sodium nitroprusside administered?
IV, short half-life, cannot be mixed with other medications.
What are the adverse effects of sodium nitroprusside?
Excessive hypotension, cyanide poisoning, thiocyanate toxicity, bradycardia, tachycardia, ECG changes.
What conditions require caution with sodium nitroprusside use?
Heart failure with reduced PVR, AV shunt, liver/kidney disease, hypothyroid, hypovolemia, fluid/electrolyte imbalance, elderly patients.
