Antihypertensives Flashcards
What does cardiac output depend on?
Venous return (venous tone, blood volume)
Heart rate
Contractility
What does total peripheral resistance?
Resistance vessel diameter
Arterial tone
What are OTC and prescription drugs that can cause hypertension?
Estrogens (oral contraceptives)
NSAIDs (nonsteroidal anti-inflammatory drugs)
Antidepressants, cyclosporin, amphetamines (stimulants)
Decreased compliance
What are other conditions that can cause hypertension?
Renal artery stenosis (renovascular hypertension)
Coarctation of the aorta
Phaeochromocytoma (catecholamine secreting tumor)
Primary hyperaldosteronism
What are three major compensatory responses to a decrease in blood pressure of the cause?
Hypovolemia (hemorrhage, dehydration) Postural Heart failure Antihypertensive Etc.
What are non pharmacological treatments for hypertension?
Sodium restriction Weight loss Exercise Limit alcohol (up to two drinks a day can be beneficial) Smoking cessation Relaxation
What are pharmacological treatment options for hypertension?
First line agents: - diuretics -ACEi and ARBs -CCBs -Beta adrenergic receptora antagonist (but not in uncomplicated hypertension) Other: -alpha 1 adrenergic antagonist -alpha 2 adrenergic agonists -vasodilators
What is uncomplicated hypertension?
When no other disease or risk factors are present
What are lifestyle recommendations for hypertension?
Healthy diet: high in fresh fruits, vegetables and low fat dairy products, low in saturated fats, and salts in accordance with Canada’s Food Guide
Regular physical activity: optimum is 45-60 minutes of moderate cardiorespiratory activity 4-5 times a week
Weight loss (over 5 kg in those who are overweight)
Reduction of alcohol consumption
Relaxation
Smoke free environment
Why are thiazides first line treatment options for hypertension?
They can potentiate other antihypertensives
May lower BP at doses that don’t perceivably alter urine flow
Are loop diuretics good options for the treatment of hypertension?
They are not great for long term treatment
They are weaker antihypertensives
They can cause extreme electrolyte imbalances
Are ACEi and ARBs good options for the treatment of hypertension?
They are first line single therapy in uncomplicated hypertension
They are recommended if concurrent condition (heart failure, left ventricle dysfunction, post-MI, diabetes, systolic dysfunction, proteinuria)
It is suggested that these agents may have benefits in addition to their blood pressure lowering
What are propranolol and metoprolol?
Beta-adrenergic receptor antagonists
What is the mechanism of beta blockers?
It’s unknown, but they work to lower blood pressure
Are beta blockers effective as single therapy?
It was thought so until recently
There may be no improvements or it might even make things worse (increased incidence of type II diabetes)
It’s unclear if it decreases cardiovascular mortality
It’s good as a second drug to block the reflex activation of the heart by the SNS
What are the problems with beta blockers?
Not metabolically neutral (may increase triglycerides and decrease HDL)
Avoid sudden withdrawal
Increased incidence of erectile dysfunction
Increased incidence of type II diabetes
Doesn’t protect against stroke
When should beta blockers be avoided?
Asthma, COPD, peripheral vascular disease, insulin dependent diabetes (use with caution), physically active (?)
When are beta blockers good?
Glaucoma, supraventricular arrhythmia, heart failure (always?), MI, angina
Everyone who is post-MI should be on a beta blocker
Sometimes these benefits override the risks above (may be used in an asthma who is post-MI or has heart failure)
What is prazosin? What does it do?
Alpha1-adrenergic receptor antagonist Not effective as single agent for chronic BP lowering (vasodilators arteries and veins) Decreases insulin resistance (good) Useful in BPH Shown to decrease nightmares in PTSD
What are the problems with prazosin?
Fluid retention with long-term treatment (give with diuretic)
First dose effect (initial large decrease in BP)
Orthostatic hypotension
What is clonidine? What does it do?
Alpha2-adrenergic receptor agonist
Acts on central vasomotor centres
Decreases sympathetic nerve activity from CNS
Autonomic system remains intact (reflexes intact; orthostasis is rare)
It’s given as two unequal doses (high dose at night)
Limited use (sedation and dry mouth)
Rebound hypertension upon rapid cessation of the drug
More common as adjunct to general anesthetic
Are vasodilators used for the treatment of hypertension?
They are not used alone for chronic blood pressure lowering
What is hydralazine? What does it do?
It’s a vasodilator
It has a greater arteriolar effect
It’s given with beta blockers and diuretics
It’s used in pregnancy
What are the problems with hydralazine?
May cause lupus like symptoms
May increase SNS activity (myocardial stimulation)
Headach, flushing nausea, hypotension, tachycardia, angina pectoris
What is minoxidil? What does it do?
Arteriolar dilator Give with a beta blocker and diuretic Given for severe hypertension (refractory) May cause pericardial effusion Hirsutism Similar problems to hydralazine
