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PHARMACOLOGY OF HYPERTENSION VICKI GROO, PHARM.D. CLINICAL ASSOCIATE PROFESSOR CLINICAL PHARMACIST, HEART CENTER

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Presentation on theme: "PHARMACOLOGY OF HYPERTENSION VICKI GROO, PHARM.D. CLINICAL ASSOCIATE PROFESSOR CLINICAL PHARMACIST, HEART CENTER"— Presentation transcript:

1 PHARMACOLOGY OF HYPERTENSION VICKI GROO, PHARM.D. CLINICAL ASSOCIATE PROFESSOR CLINICAL PHARMACIST, HEART CENTER

2 OBJECTIVES Classify hypertension and define treatment goals Be able to describe the pharmacology of oral antihypertensives with considerations in drug choice and compelling indications Be able to describe the pharmacology of intravenous antihypertensives used in the treatment of hypertensive emergency

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4 CLASSIFICATION SBPDBP Normal< 120and< 80 Prehypertension or80-89 Hypertension Stage or90-99 Stage 2≥ 160or≥ 100 **Adults (  18 yo) **Avg of  2 readings,  2 mins apart, on  2 occasions Secondary HTN only accounts for 5-10% of population JAMA 2003;289:

5 EPIDEMIOLOGY 31% of US population with HTN 30% of US population with pre-HTN Present in: 69% of patients who present with 1 st MI 77% of patients who present with 1 st stroke 74% of patients with heart failure Only 47% have BP under control

6 NATIONAL HEALTH & NUTRITION EXAMINATION SURVEY % 73% 50%

7 TREATMENT GOALS JNC-7 REDUCE MORBIDITY AND MORTALITY Measurable goal: Prehypertension: <120/80 HTN w/ diabetes or renal disease: <130/80 Others: <140/90 Minimize/ control other CV risk factors Reduce/ minimize adverse drug effects JAMA 2003;289:

8 AHA BP TARGETS 2007: For prevention and management of ischemic heart disease: Circulation 2007:115: *Don’t worry about learning these for now. They may change

9 ALGORITHM FOR TREATMENT OF HYPERTENSION Not at Goal Blood Pressure (<140/90 mmHg) (<130/80 mmHg for those with diabetes or chronic kidney disease) Initial Drug Choices Drug(s) for the compelling indications Other antihypertensive drugs (diuretics, ACEI, ARB, BB, CCB) as needed. With Compelling Indications Lifestyle Modifications Stage 2 Hypertension (SBP >160 or DBP >100 mmHg) 2-drug combination for most (usually thiazide-type diuretic and ACEI, or ARB, or BB, or CCB) Stage 1 Hypertension (SBP 140–159 or DBP 90–99 mmHg) Thiazide-type diuretics for most. May consider ACEI, ARB, BB, CCB, or combination. Without Compelling Indications Not at Goal Blood Pressure Optimize dosages or add additional drugs until goal blood pressure is achieved. Consider consultation with hypertension specialist. JNC VII JAMA 2003;289:

10 DRUG THERAPY CONSIDERATIONS Clinical trial data Over 2/3 of patients will require ≥2 drugs Cost/ adverse effects JAMA 2003;289:

11 Lifestyle Modifications Physical activity Lose weight Limit salt intake Limit alcohol intake DASH eating Plan

12 PHARMACOLOGY OF ANTIHYPERTENSIVES Diuretics: Deplete sodium thereby decreasing blood volume Agents that block production or action of angiotensin Reduce peripheral vascular resistance Potentially ↓ blood volume Sympathoplegic agents: ↓ peripheral vascular resistance Inhibit cardiac function ↑ venous pooling in capacitance vessels Direct vasodilators: Relax vascular smooth muscle, thus dilating resistance vessels

13 DIURETIC MOA

14 HCTZCTDIndapamide benzothiadiazinethiazide-likeNon-thiazide sulfonamide VD2.5 L3-13 L25 L T ½8-15 hours45-60 hours14 hours duration16-24 hours48-72 hours 24 hr SBP(-) 7.4 ± 1.7(-) 12.4 ± 1.8 PM BP(-)6.4 ± 1.8(-) 13.5 ± 1.9 Hypertension 2004;43:4-9, DIURETIC COMPARISON Indapamide P = and for 24 hr and pm BP respectively

15 DIURETIC CONSIDERATIONS KDoseOther Thiazides:1 st line choice Hydrochlorothiazide↓ mg/d Chlorthalidone↓ mg/d Metolazone↓↓↓ mg/dReserve for resistant edema Indapamide mg/d1 st line choice elderly Aldosterone AntagReserve for resistant HTN or HF Spironolactone↑ mg/d avoid K > 5.0 or CrCl < 30 Eplerenone↑ mg/d avoid K > 5.0 or CrCl < 30 K sparingCaution, ACE/ARB, renal failure Amiloride↑5- 20 mg/dUse in combo to counteract K loss Triamterene↑ mg/dCombo product with HCTZ available LoopReserve for HF or resistant edema Furosemide↓20-80 mg/dBioavailability 60% or less Bumetanide↓0.5-4 mg/dBioavailability 80% Torsemide↓5-10 mg/dBioavailability 80% Goodman and Gilmans: The Pharmacologic Basis of Therapeutic 12 th edition:

16 DIURETICS Compelling Indications: Heart Failure High CAD risk Diabetes Recurrent Stroke Prevention Monitoring Electrolytes after initiation or dose increases Every 6-12 months K sparing, every 3 months if also on RAAS inhibitor Side Effects Increase glucose Increase uric acid — precipitate gout dehydration — orthostatic hypotension Spironolactone — gynecomastia

17 MECHANISM OF ACTION

18 ACE INHIBITORS DrugDose Captopril mg tid Enalapril mg/day Lisinopril5-40 mg/day Benazepril5-80 mg/day Fosinopril*10-80 mg/day Moexipril mg/day Quinapril5-80 mg/day Ramipril mg/day Perindopril2-16 mg/day Trandolapril1-8 mg/day ARBS DrugDose Candesartan (Atacand)*4-32 mg/d Eprosartan (Tevetan)* mg/d Irbesartan (Avapro)* mg/d Losartan (Cozaar)* mg/d Omelsartan (Benicar)20-40 mg/d Telmisartan (Micardis)40-80 mg/d Valsartan (Diovan) mg/d Goodman and Gilmans: The Pharmacologic Basis of Therapeutic 12 th edition: * Dual elimination: liver & kidney * generic Combining with thiazide usually more effective than dose increase Direct Renin Inhibitors Aliskiren (Tekturna) mg/day As effective as ACE or ARB in HTN

19 ACE INHIBITORS AND ARB Compelling Indications Systolic Heart Failure DM CKD with Proteinuria CAD Monitoring 1-2 weeks after initiation or dose change for K & Cr Every 6 months on stable doses Side Effects Dry Cough  Switch to ARB Angioedema: ARB likely okay, consider severity Hyperkalemia: supplements, diet, worsening renal fxn Combining RAAS inhibitors is generally not recommended No added benefit CV or renal outcomes / Increased toxicity ACE or ARB + aldosterone antagonist is the exception Avoid in Pregnancy

20 BETA BLOCKERS MOA: Sympatholytic  ↓ HR and CO / ↓ release of renin Goodman and Gilmans: The Pharmacologic Basis of Therapeutic 12 th edition: Receptor Affinity Lipid Solubility Renal Elimination Dose Atenololβ1β1LowYes mg/d Bisoprololβ1β1LowNo mg/d Carvedilolβ1, β2, αModNo mg bid Labetalolβ1, β2, αLowNo mg bid Metoprolol tartrate Metoprolol succinate β1β1ModNo mg bid mg/d Nebivololβ1β1LowNo5-40 mg/d Propranololβ1, β2HighNo mg bid Avoid sudden discontinuation  Rebound HTN d/t up regulation of receptors

21 BETA BLOCKERS Compelling Indications CAD Systolic Heart Failure Monitoring ECG if bradycardic-  AV block Avoid combining with other AV nodal blocking agents Side Effects Bronchoconstriction—Reactive Airway Disease Choose B1 selective agent and keep at lower doses Metabolic— ↓HDL, ↑ LDL and triglycerides Diabetes—↓ insulin sensitivity Mask symptoms of hypoglycemia, delay recovery Carvedilol may have advantage as it ↑’s insulin sensitivity Peripheral Vascular Disease—↑ symptoms, use B1 selective Depression—Choose agent with low lipid solubility Fatigue

22 CALCIUM CHANNEL BLOCKERS

23 CCB CONSIDERATIONS AV Node SA Node ContractilityVasodilation DHP Nifedipine^0115 Amlodipine0115 Felodipine0115 Nicardipine0105 Non-DHP# Diltiazem^4223 Verapamil^5443 Goodman and Gilmans: The Pharmacologic Basis of Therapeutic 12 th edition: ^ Do not use short acting agents in treatment of HTN # Do not combine with beta-blockers: increased risk of bradycardia Doses provided in Dr DiDomenico’s lecture on angina

24 CALCIUM CHANNEL BLOCKERS Compelling Indications High CAD risk Diabetes Monitoring / Side Effects Dihydropyridine (DHP) peripheral edema reflex tachycardia dizziness Non DHP Bradycardia Contra-indicated in heart failure Constipation (especially verapamil)

25 VASODILATORS: ALPHA-1 BLOCKERS Doxazosin: start 1 mg daily: max 8 mg daily Prazosin: start 1 mg bid-tid: max 15 mg/day Terazosin: start 1 mg qhs: max 20 mg/day

26 VASODILATORS: ALPHA-1 BLOCKERS Compelling Indications: None Second line therapy Also used to treat BPH (benign prostatic hypertrophy) Monitoring: Na and H20 retention with high doses Side Effects: Dizziness — Orthostatic hypotension, first dose syncope Headaches Reflex tachycardia Fatigue

27 VASODILATORS: DIRECT MOA: vascular smooth muscle relaxation Compelling Indications: None Second line therapy: Resistant HTN Hydralazine 10 – 50 mg qid; max 300 mg /day Often dosed bid or tid to improve adherence Rare but serious SE: Lupus erythematosus, blood dyscrasias, peripheral neuritis Headaches, tachycardia, angina, nausea, diarrhea, rash Minoxidil Start 5 mg daily; usual mg daily; max 100 mg daily Rare but serious SE: Stevens-Johnson syndrome Hypertrichosis — used topically to promote hair growth Headache, edema, tachycardia, paresthesia

28 VASODILATORS: DIRECT Caution: Increased myocardial work Use in combination with B-blocker / diuretic to combat these effects

29 CENTRAL ALPHA 2 AGONISTS Bind to and activate α2 receptors in the brain ↓ sympathetic outflow to the heart → CO and HR ↓ sympathetic outflow to vasculature → ↓ vascular tone

30 CENTRAL ALPHA 2 AGONISTS Compelling Indications: None Second line therapy: Resistant HTN Clonidine Start 0.1 mg bid, titrate up weekly: max 2.4 mg/day Available as a transdermal patch changed weekly Severe rebound HTN if stopped abruptly Side Effects: sedation, depression, bradycardia + many more Methyldopa Start mg bid-tid, adjust every 2-3 days, max 3gm/day Can be used in pregnancy Serious but uncommon SE: blood dyscrasias, myocarditis, pancreatitis Side effects: sedation, orthostatic hypotension + many more

31 ANTIHYPERTENSIVES: Centrally Acting: Methlydopa Clonidine Sedation, dry mouth B-blockers: Atenolol Carvedilol Metoprolol Propranolol Bradycardia α 1 blocker: Prazosin, Doxazosin, Terazosin Dizziness, edema Vascular Smooth Muscle: Hydralazine, Minoxidil CCBs Headache, Dizziness, edema, Diuretics: Thiazide Loop Other hypokalemia AngiotensinogenAngiotensin I Angiotensin II Renin Aliskiren ACE ACE Inhibitors ARBs Hyperkalemia, dry cough

32 ALGORITHM FOR TREATMENT OF HYPERTENSION Not at Goal Blood Pressure (<140/90 mmHg) (<130/80 mmHg for those with diabetes or chronic kidney disease) Initial Drug Choices Drug(s) for the compelling indications Other antihypertensive drugs (diuretics, ACEI, ARB, BB, CCB) as needed. With Compelling Indications Lifestyle Modifications Stage 2 Hypertension (SBP >160 or DBP >100 mmHg) 2-drug combination for most (usually thiazide-type diuretic and ACEI, or ARB, or BB, or CCB) Stage 1 Hypertension (SBP 140–159 or DBP 90–99 mmHg) Thiazide-type diuretics for most. May consider ACEI, ARB, BB, CCB, or combination. Without Compelling Indications Not at Goal Blood Pressure Optimize dosages or add additional drugs until goal blood pressure is achieved. Consider consultation with hypertension specialist. JNC VII JAMA 2003;289:

33 INADEQUATE BP RESPONSE WITH INITIAL AGENT Increase dose Substitute new drug from different class Little to no response to initial drug No compelling indication for the drug Troublesome SE Add a new drug from a different class Initial drug produces some response and is well tolerated Compelling indication for the initial drug Add thiazide if not used initially

34 HTN: SPECIAL POPULATIONS Elderly Isolated systolic HTN common SBP rises and DPB declines with aging Generally salt sensitive Use lower initial drug doses and slower dose titration Avoid  1 -blockers, labetalol, central  2 agonists JNC-8 – higher BP goal? AHA Consensus Statement on the Elderly 2011 Goal SBP < 140 mm Hg Age > 80, goal SBP < 150 mmHg No evidence for lower BP goals for elderly patients at high risk, eg DM, CAD, CKD. Maintain DBP > 65 mmHg --- coronary perfusion Circulation 2011;123:

35 HTN ELDERLY GUIDELINES Canada 2013 In the very elderly (age ≥ 80), the target for SBP should be < 150 (grade C) No changes for those age 65-79; ie goal remains at < 140/90 Europe 2013 In elderly < 80 years old with SBP ≥160 mmHg there is solid evidence to reducing SBP to 150 and 140 mmHg (IA) In fit elderly patients < 80 years old SBP values <140 mmHg may be considered, whereas in the fragile elderly population SBP goals should be adapted to individual tolerability (IIb C) If > 80 years and with initial SBP ≥160 mmHg, it is recommended to reduce SBP to between 150 and 140 mmHg provided they are in good physical and mental conditions (IB) Benefit in treating elderly, ↓ stroke, CV events, heart failure Canadian Journal of Cardiology 2013;29:

36 HTN: SPECIAL POPULATIONS African Americans Prevalence, severity and impact increased compared to other populations Onset at younger age More Na + sensitive, lower plasma renin activity Good response to Na restriction and diuretic therapy  response to ACE inhibitors, ARBs, and  -blockers as monotherapy HOWEVER, can be overcome by adding a diuretic Still indicated if compelling indication exists! ACE inhibitor angioedema 2-4 x more frequent

37 HYPERTENSIVE CRISIS

38 HYPERTENSION CRISES EMERGENCY BP >180/120 Acute Target Organ Damage Life threatening GOAL:  BP now IV therapy URGENCY BP >180/120 No Target Organ Damage Not life-threatening GOAL:  BP over days Oral therapy

39 HYPERTENSIVE EMERGENCIES Heart Acute coronary syndrome Acute heart failure with pulmonary edema Dissecting aortic aneurysm CNS Intra-cerebral hemorrhage / CVA Encephalopathy Eclampsia Acute Renal Failure Eyes: Papilledema, hemorrhage

40 Goal: Lower MAP no greater than 20-25% in a few hours Maintain DBP mmHg Too rapid or too much  cerebral hypoperfusion Continuous BP monitoring TREATMENT FOR HYPERTENSIVE EMERGENCIES IV Vasodilators Sodium Nitroprusside Nicardipine Nitroglycerin Enalaprilat Fenoldopam Hydralazine IV Adrenergic Inhibitors Labetalol Esmolol Phentolamine

41 IV VASODILATORS MOAIndication NitroprussideVasodilator*Most HTN emergencies Caution high ICP or azotemia NicardipineCCBMost HTN emergencies Except acute heart failure Caution coronary ischemia NitroglycerinVasodilator*Coronary Ischemia EnalaprilatACE inhibitorAcute heart failure Avoid in acute MI FenoldopamDopamine 1 agonist*Most HTN emergencies Caution glaucoma HydralazineDirect vasodilatorEclampsia * See next slide

42 IV VASODILATORS: MOA Pro drugRelease Nitroprusside: arteriole and venous No tolerance Less effect on HR Nitroglycerin 1° venodilator Arteriole dilator at high doses + tolerance Fenoldopam D1 receptor agonist moderate affinity α2 vasodilation

43 IV VASODILATORS DoseOnsetAdverse Effects Nitroprusside ug/minimmediateThiocyanate Cyanide toxicity Nicardipine5-15 mg/hr5-10 min↑ HR, HA, flushing Nitroglycerin5-100 ug/min2-5 minHA, vomiting Tolerance with prolonged use Enalaprilat mg q6h15-30 minHigh renin states: ↓↓↓ BP Variable response Fenoldopam ug/kg/min< 5 min↑ HR, HA, flushing, nausea Hydralazine10-20 mg IV mg IM min min ↑ HR, HA, flushing, vomiting, angina Duration of action varies from 1-2 min to 6 hours

44 NITROPRUSSIDE TOXICITY Metabolism releases CyanideIncreased Risk if: Rate at ≥ 5 ug/kg/min 2 ug/kg/min for prolonged use (24-48 hours) Renal insufficiency Can administer Na Thiosulfate to enhance metabolism of cyanide Cyanide Toxicity Weakness Headaches Vertigo Confusion / giddiness Perceived difficulty breathing Thiocyanate Toxicity Anorexia / nausea Fatigue Toxic psychosis

45 IV ADRENERGIC BLOCKERS MOAIndication LabetalolB1, B2, α blockerMost HTN emergencies Except acute heart failure EsmololB1 blockerAortic dissection Perioperative Phentolamineα antagonistCatecholamine excess DoseOnset (min) Adverse Effects Labetalol20-80 mg q 10 min mg/min 5-10Heart block Esmolol ug/kg/min x 1 min ug/kg/min x 4 min 1-2Hypotension, nausea Phentolamine5-15 mg1-2↑ HR, HA, flushing Duration of action varies from 3-10 min to 6 hours


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