Define the stages of hypertension and differentiate between essential and secondary HTN
Stage I - 140-159/90-99
Stage II - >160/>100
Essential - no known cause (95% patients)
Secondary - caused by another medical problem
Name potential causes of secondary HTN (4 main categories and specific diseases within each)
- renal (CKD, renal artery stenosis)
- drugs (ETOH, oral contraception, NSAIDS, TCAs, MAOIs, appetite suppressants)
- endocrine (pheochromocytoma, Cushings, hyperaldosteronism, hypo/hyperthyroid, hyperPTH)
- pulmonary (obstructive sleep apnea)
Name factors contributing to HTN that are modifiable
- sodium intake, diets low in potassium and calcium
- obesity or sedentary lifestyle
- heavy ETOH intake
- meds
- stress
Name factors contributing to HTN that are NOT modifiable
- genetics
- race
- gender
- age
What two demographics have a higher risk of end organ disease, and therefore should be treated more aggressively?
- African Americans and premenopausal women
What is the ultimate effect of using diuretics to treat HTN?
- decrease intravascular volume and reduce preload
What is the effect of using angiotensin blockers to treat HTN?
- inhibit production/action of angiotensin II (a potent vasoconstrictor) to therefore reduce PVR
What is the effect of using direct vasodilators to treat HTN?
- relax vascular smooth muscle and reduce PVR
What is the effect of using sympathoplegic agents to treat HTN?
- decrease sympathetic tone and reduce PVR
What effects do antihypertensive medications have on the plasma volume?
- all antihypertensives (especially sympatholytics) increase plasma volume, except diuretics (which decrease) and ACEI/ARBs/renin inhibitors (no effect)
- increasing volume can be bad for a hypertensive patient!
What are indications for use of loop diuretics, thiazide diuretics, and potassium sparing diuretics in the setting of HTN?
- loop - high potency, used acutely in extreme HTN, CHF, cirrhosis, acute renal failure (prostaglandins vasodilate)
- thiazides - medium potency, used long term for mild-moderate HTN
- potassium sparing - low potency, used in combo with above to prevent hypokalemia
When comparing ACEIs and ARBs, how does each work and which is more potent in treating HTN?
ACEIs: blocks ACE (no conversion to angiotensin II), inhibits breakdown of bradykinin (a vasodilator)
ARBs:competitive receptor binding of angiotensin II
ACEIs are more potent! Can also remodel heart in a good way
What are the side effects of ACEIs and ARBs?
- cough (ACEIs only)
- hypotension
- decreased renal function (efferent vasodilation to decrease GFR - this is what you want in chronic kidney disease!)
- angioedema
List the short acting ACEI, the longer acting ACEIs (5), and the ARBs (3)
SA ACEI: captopril
LA ACEI: lisinopril, benazepril, quinapril, ramipril, enalapril
ARB: losartan, valsartan, irbesartan
How does aliskirin work?
- renin inhibitor, but its not very effective
What calcium channel blocker is most frequently used for HTN, and what are the effects on BP, HR, and contractility?
- dihydropyridines (amlodipine) which inhibit contraction of vascular smooth muscle
- LOWER BP, have no effect on HR or cause slight reflex tachycardia, and have no effect on contractility
What beta blocker is used for difficult to treat HTN?
labetolol
A 45 yo male presents to your office with a history of HTN that has been difficult to control. You have ruled out any potential secondary causes. You notice he is also balding! What do you prescribe?
- minoxidil, which opens K channels and results in arteriolar vasodilation
In general, what are the side effects you expect from drugs that treat hypertension by altering the SNS (alpha2 agonists, alpha1 antagonists, beta blockers)
- no reflex tachycardia
- orthostatic hypotension
- increased secretions, GI/GU disturbances (PNS takes over)
What antihypertensives can be used in pregnancy?
- alpha methyldopa (alpha 2 agonist)
- hydralazine (NO)
