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USMLE - Pharm
Kaplan Section 3 Chapter 3 AntiHypertensive Drugs
Question | Answer |
---|---|
Name the 4 strategies to combat HTN with drugs | 1. reduce blood volume 2. reduce SANS tone 3. reduce vagal tone 4. relaxation of vascular smooth muscle |
What are the 4 determinants of BP? | 1. CO - heart rate (not enough vagal tone --> HR too fast), 2. CO - contractility (too much SANS tone, B1), 3. peripheral resistance (too much SANS tone, a1), 4. body fluid volume (edema, too much renin, or too much ANGII --> too much Na and H2O retention |
What are the drugs that combat the 4 determinants of BP? | 1. CO - heart rate (B blockers, CaCB's), 2. CO - contractility (B blockers), 3. peripheral resistance (anti-adrenergics, CaCB's, direct vasodilators, diuretics), 4. body fluid volume (diuretics, ACEi, ANGII antagonists) |
What are the three anti-hypertensives that actually prolong survival? | Live longer by ACEing THe Bank. 1. ACEi's, 2. thiazide diuretics, 3. B blockers |
Name the sympathoplegics used in antiHTN therapy | a2 agonists: a-methyldopa, clonidine; dec NE release: reserpine, guanethidine; a1 blockers: prazosin, doxazosin, terazosin; B blockers - propranolol |
Name the direct-acting vasodilators used in anti-HTN therapy. | Hydralazine, Nitroprusside, Minoxidil, Diazoxide |
Hydralazine | activate NO/EDRF pathway --> arteriolar dilation --> dec TPR (esp cerebral, coronary, renal); used in mod to severe HTN. |
Side effects of hydralazine | headache, flushing, sweating, fluid retention (use diuretic), reflex tachy (use B blocker), if slow acetylator --> SLE-like syndrome |
Nitroprusside | pro-drug --> sulfonation --> opens K+ channels --> membrane hyperpolarization --> arteriolar vasodilation; inc renin --> renal vasodilator. Used in mod to severe HTN. |
Side effects of nitroprusside | headache, flushing, sweating, fluid retention (use diuretic), reflex tachy (use B blocker), pulm HTN due to volume shifts, hypertrichosis (excessive hair growth). |
Diazoxide | K+ channel opening --> arteriolar vasodilation --> reflex tachy, inc CO, inc renin. Used IV for HTN emergencies, used to treat insulinoma (dec insulin secretion), relaxes uterine sm musc. |
Side effects of diazoxide | fluid retention (use diuretic, but not thiazide), tachy (use B blocker), dec insulin release --> hyperglycemia |
What is the difference between captopril and losartan? | Captopril = ACEi. Losartan = AT-1 receptor antagonist. Losartan blocks downstream from Captopril so that it avoids affecting bradykinin. |
Why should you use ACEi or AT-1 antagonists for diabetics? | Both dec vasoconstriction and BP --> dec glomerular efferent resistance --> slow development and progression of nephropathy. |
What are the adverse effects of ACEi and AT-1 antagonists? | hypotension, hypovolemia, dry cough (with ACEi's), hyperkalemia, acute renal failure (if have renal artery stenosis), angioedema. |
What population should avoid ACEi's and AT-1 antagonists? | pregnant women. Teratogen --> fetal hypotensio, renal failure, skull and renal malformations. |
What is recommended for the initial drug treatment fo mild to moderate HTN? | B blocker or thiazide diuretic as DOC's. |
If angina and HTN, use what? | B blockers, CaCB's |
If Diabetes and HTN, use what? | ACEi's, AT-1 antagonists |
If Heart failure and HTN, use what? | ACEi's, AT-1 antagonists |
If post-MI and HTN, use what? | B blockers |
If BPH and HTN, use what? | a blockers |
If dyslipidemias and HTN, use what? | a blockers, CaCB's |