Medications for Treating Hypertension

Jeannie Collins Beaudin, RPhKeswick Pharmacy 1

WIDESPREAD PROBLEM...

CANADIAN STATISTICS:More than 1 in 5 adults have hypertension

(22%)46% of Canadians age 55-65

42% - No diagnosisOnly 16% are controlled9% of those with diabetes (more stringent

targets)

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IMPORTANCE OF NURSES’ ROLE

Nurses have:Frequent patient contactPatient trustFavourable financial model

Educational role

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...PART OF THE PICTUREMETABOLIC SYNDROME:

HypertensionInsulin resistanceHypercholesterolemia Abdominal weight gainProthrombic statePro-Inflammatory state

All are risk factors for cardiovascular disease#1 cause of death

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CAUSES OF METABOLIC SYNDROME

Obesity InactivityPoor dietUnknown genetic factorsStress?

Cortisol Increases BP, heart rate, lipids, blood glucose Weight gain around waist

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KEY CHEP MESSAGES...Need to assess overall CVD riskCombination of drug therapy and lifestyle

changes are most effectiveMonitor regularly when above target

Regular screening for all adultsFocus on adherence

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ADHERENCEAssess regularly

Encourage patients to bring bottles Check date filled and amount remaining

Fit to daily scheduleStrive for once daily dosing

Long-acting formulasFixed-dose combinations

Fewer pills per dayOften more expensive, not covered

Use unit-of-dose packagingImprove patient educationEncourage patient involvement in monitoring

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TYPES OF HYPERTENSION MEDICATIONSThose that affect hormone systems

Beta-blockersACE Inhibitors (angiotensin converting enzyme

inhibitors)ARBs (angiotensin receptor blockers

Those that affect electrolytesFluid balance

Diuretics Vasodilation

Calcium channel blockers

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ABCs OF HYPERTENSION MEDS

A. Angiotensin Converting Enzyme Inhibitors (ACE-I), Angiotensin Receptor Blockers (ARB)

B. Beta-BlockersC. Calcium channel blockers (CCBs)D. DiureticsE. “Everything else”... Alpha-Blockers

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ACE-InhibitorsEnd with “-pril”Block the enzyme that converts Angiotensin I to

Angiotensin IIAlso reduce morbidity/mortality of

HF, angina, stroke, DM neuropathyGenerally well tolerated

25% can develop dry cough ACE enzyme also block breakdown of bradykinin (xs

causes cough)

Teratogenic – caution in pre-menopausal women

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ANGIOTENSIN RECEPTOR BLOCKERS (ARBs)End with “-sartan”Block the effect of Angiotensin II instead of

blocking productionActions similar to ACE-I

But does not affect bradykininNo cough side effect

Better toleratedMore expensive

Also teratogenic

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BETA-BLOCKERSEnd with “-olol”“Beta adrenergic receptor blockade”

Block beta receptors for adrenalinBeta-1, Beta-2 receptors

Beta-1 - heart, blood vessels Beta-1 selective BB’s (e.g. Atenolol, Metoprolol)

Beta-2 - lungs, brain Non-selective BB’s (e.g. Propranolol, Nadolol)

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BETA-BLOCKERSBETA-2:Lungs

Bronchodilation Site of action of Salbutamol (beta-agonist)

BrainDreamingMigraine

Beta-blockers can decrease frequency

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BETA-BLOCKERSBlock action of adrenalin and beta(adrenalin)

agonists on lungs:Can worsen bronchospasm, asthmaBlock action of inhaled Salbutamol

Can be useful for blocking essential tremor

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BETA-BLOCKERSDisadvantages:

Slow heart rate, lower blood pressure (fatigue)Reduce blood flow to extremities (cold hands, feet,

impotence)Less heart-selective can increase dreamingIncrease risk of diabetes (especially with diuretics)Not recommended over 65 years

Advantages:Reduce mortality post-MIAlso useful for HF, anginaNon-cardio selective can prevent migraineInexpensive

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CALCIUM CHANNEL BLOCKERS

Calcium is necessary for smooth muscle contraction

Calcium enters cells via tiny channelsBlocking calcium channel inhibit muscle

contraction Vasodilation Reduced force of heart muscle contraction

Affect heart, blood vessels – not skeletal muscle

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CALCIUM CHANNEL BLOCKERSThree types:Dihydropyridines (DRPs) - end with “-dipine”

Amlodipine, Felodipine, NifedipinePhenylalkylamines

VerapamilBenzothiazepines

Diltiazem

Last 2 have similar characteristics Often referred to as “non-dihydropyridines” (non-DRPs)

Essentially 2 classes now: DRPs and non-DRPs

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CALCIUM CHANNEL BLOCKERSDIFFERENT SITES OF ACTION:DRPs (-dipines) act mainly on blood vessels

“vasodilating” Excess relaxation -> peripheral edema Adversely affect renal function in diabetes

Non-DRPs (verapamil, diltiazem) also act on heart “modulating”

Verapamil has the strongest effect on heart Diltiazem is “middle of the road” Both slow conduction of impulse through AV node

Caution with 2nd and 3rd degree heart block Avoid in heart failure Renal protective

Preferable if risk of diabetes or kidney damage

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CALCIUM CHANNEL BLOCKERSNo effect on:

Insulin secretion or actionBlood glucosePlasma protein levelsPotassium balanceMagnesium balance

Grapefruit interactionAmlodipine, felodipine

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CALCIUM CHANNEL BLOCKERSShort-acting nifedipine

Spike in norepinephrine, transient rise in plasma renin Reflex tachycardia, BP rise No longer used for emergency hypertension

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DIURETICSEnd with “-ide”

Hydrochlorothiazide, indapamide, furosemideAct on kidney to increase fluid excretion

Reduced blood volume -> reduced pressure Thiazides – act on tubules Furosemide - “Loop” diuretic, more potent

Most cause loss of potassium Increased risk of electrolyte imbalances Exceptions “potassium sparing”:

Spironolactone (Aldactone) Amiloride (in Moduret, Apo-Amilzide), Triamterene (in Dyazide, Apo-Triazide, Nov0-

Triamzide )21

DIURETICSMany side effects:

Lethargy, reduced exercise tolerance, polyuriaHypokalemia

Skeletal muscle weakness, GI hypomotility (ileus, constipation)

Leg cramps, arrhythmiaCan precipitate gouty arthritis (increased uric

acid)Adverse effect on glucose and lipids (especially

with B-Blockers) Poorer compliance noted than with other classes

Very inexpensive, effective22

“EVERYTHING ELSE”ALPHA BLOCKERSEnd with “-azosin”

Prazosin, terazosinAlso used for enlarged prostate

Block alpha adrenalin receptorsStrong rapid blood pressure reduction

Dose must be started low and raised slowlySide effect:

Postural hypotension (may be severe)

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CONCLUSION...HTN is most important cause of stroke,

angina and renal and heart failureMost important key for successful treatment

is patient education

Important to focus on multiple CV risk factors:10% in BP + 10% in TC = 45% in CVD!

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QUESTIONS?

THANK YOU!THANK YOU!

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