1/2 Flashcards
Which vasodilator drugs dilate veins more than arteries? Which vasodilator drugs dilate arteries more than veins? Which one cases marked orthostatic hypotension?
Nitrates dilate veins more than arteries (predominantly decrease preload -> significant orthostatic hypotension, little effect on afterload)
Calcium channel blockers and hydralazine dilate arteries more than veins (predominantly decrease afterload, little effect on preload so no orthostatic hypotension)
Which vasodilator can lead to cyanide toxicity after prolonged use?
nitroprusside
What is difference in target selectivity of the dihydropyridines and non-dihydropyridines?
Dihydropyridines (nifedipine, amlodipine) have greater selectivity for vasculature smooth muscle than cardiac muscle
Diltiazem has equal selectivity for vascular smooth muscle and cardiac muscle
Verapamil has a greater selectivity for cardiac muscle than vascular smooth muscle
Why should you never combine diltiazem or verapamil with Beta blockers?
because diltiazem and verapamil both slow the heart rate and decrease contractility. If combined with beta blockers, complete heart block can ensue.
What are the effects of hydrazine? What drug does it need to be combined with?
direct arteriolar vasodilation but no negative chronotropic effects on the heart -> reflex tachycardia
Must be combined with a beta blocker to prevent reflex tachycardia
Which ACE inhibitor is best for acutely ill patients with CHF who need rapid reduction of afterload? Why?
Captopril has a short half life and thus can be rapidly titrated up to the maximum tolerated dose
What conditions promote binding of digoxin to the Na+K+ ATPase and can induce digoxin toxicity?
hypokalemia. Don’t put someone on both a non-potassium sparing diuretic and digoxin at the same time!
What receptors does dopamine bind? How does dopamine effect the heart?
Dopamine binds to alpha1 receptors on vascular smooth muscle (vasoconstriction and increased SVR) and Beta1 receptors on the heart (increase HR and contractility)
At low doses, dopamine binds to receptors in the renal vasculature (D1 receptors), causing renal vasodilation and increased renal perfusion
What receptors does dobutamine bind?
Beta1 receptors on the heart, but not alpha1 receptors -> increased CO -> baroreceptor reflex -> decreased SVR
Which class of antihypertensive drugs can increase uric acid levels and cause hyperuricemia/gout?
thiazide diuretics
Why is it critical that patients do not take aspirin and ibuprofen/naproxen at the same time?
Aspirin is a strong, irreversible inhibitor of both COX1 and COX2 but ibuprofen is a weak, reversible inhibitor that prevents aspirin from inactivating that enzyme. In the presence of both aspirin and ibuprofen, COX activity increases, losing the protective anti platelet effects afforded by aspirin therapy
Which antihypertensive drugs are likely to cause coronary vasospasm?
beta blockers because blocking Beta2 receptors leaves the vasoconstrictor effects of the alpha1 receptors unopposed
What class of antihypertensive drugs are absolutely contraindicated in pregnancy? What drug would be a good alternative for pregnant women?
ACE inhibitors and ARBs so not be administered to pregnant women or women of childbearing age.
Methyldopa and hydralazine are the preferred antihypertensive drugs for pregnant women
What anticoagulant class drug inhibit clots by blocking ADP receptors on platelets? by inhibiting thromboxane A2 synthesis? by inhibiting free and clot-bound thrombin?
clopidogrel is a antagonist of ADP receptors on platelets
Aspirin blocks TXA2 synthesis via cyclooxygenase
bivalirudin inhibits free and clot-bound thrombin
What is phenylephrine’s mechanism of action?
a nonselective alpha agonist
