Podcast
Questions and Answers
What is the primary mechanism by which antihypertensive drugs exert their effect on blood pressure?
What is the primary mechanism by which antihypertensive drugs exert their effect on blood pressure?
Which type of hypertension is primarily associated with identifiable abnormalities in the body?
Which type of hypertension is primarily associated with identifiable abnormalities in the body?
How do the kidneys contribute to long-term blood pressure management?
How do the kidneys contribute to long-term blood pressure management?
What defines primary or essential hypertension?
What defines primary or essential hypertension?
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Which of the following statements accurately describes the role of the baroreceptor reflex in blood pressure regulation?
Which of the following statements accurately describes the role of the baroreceptor reflex in blood pressure regulation?
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What is the primary difference in the approach to treating secondary hypertension compared to primary hypertension?
What is the primary difference in the approach to treating secondary hypertension compared to primary hypertension?
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In the equation BP = CO x SVR, what does SVR stand for?
In the equation BP = CO x SVR, what does SVR stand for?
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How does the baroreceptor reflex contribute to blood pressure regulation?
How does the baroreceptor reflex contribute to blood pressure regulation?
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Which of the following is NOT an example of a condition that can lead to secondary hypertension?
Which of the following is NOT an example of a condition that can lead to secondary hypertension?
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What mechanism do antihypertensive drugs primarily influence to lower blood pressure?
What mechanism do antihypertensive drugs primarily influence to lower blood pressure?
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In the context of blood pressure management, what role do the kidneys play?
In the context of blood pressure management, what role do the kidneys play?
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What is the key feature of primary or essential hypertension?
What is the key feature of primary or essential hypertension?
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Which physiological response is NOT altered by antihypertensive drugs?
Which physiological response is NOT altered by antihypertensive drugs?
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Which factor is primarily considered when distinguishing between primary and secondary hypertension?
Which factor is primarily considered when distinguishing between primary and secondary hypertension?
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Study Notes
Antihypertensive Drugs, Treatment of Angina Pectoris and Cardiac Arrhythmias
- The presentation covers antihypertensive drugs, treatment of angina pectoris, and cardiac arrhythmias
- Objectives include discussing mechanisms, indications, side effects of medications used to treat hypertension, angina pectoris, and cardiac arrhythmias, and how patient use of drugs may impact therapy.
Antihypertensives
- Blood pressure (BP) is a product of cardiac output (CO) and systemic vascular resistance (SVR)
- BP = CO x SVR
- BP is controlled in the body by the baroreceptor reflex, which monitors and corrects changes in BP within seconds.
- Kidneys manage BP long-term by controlling fluid balance.
- Antihypertensive drugs impact CO, SVR or both.
Hypertension
- Two categories of hypertension: secondary and primary (essential)
- Secondary hypertension is caused by an underlying abnormality (e.g., kidney disease, renal artery stenosis, endocrine disorders). It accounts for less than 10% of hypertension cases.
- Primary or essential hypertension accounts for about 90% of cases and has no clear cause.
Possible Causes of Essential Hypertension
- Genetic predisposition, stress, diet, cigarette smoking, alcohol abuse, and obesity can all impact sympathetic activity and ultimately cause increased blood pressure. This also causes changes in the peripheral vascular system—the peripheral vessels become less compliant and resistance increases.
Hypertension and Metabolic Abnormalities
- Hypertension is associated with metabolic abnormalities
- These include impaired glucose metabolism (due to insulin resistance), hyperinsulinemia, dyslipidemia, and abdominal obesity, all collectively known as metabolic syndrome.
Drug Management
- Common hypertension drugs include diuretics, sympatholytics, vasodilators, drugs that inhibit the renin-angiotensin system, and calcium-channel blockers.
Diuretics
- Their use in treating hypertension stems from increasing renal excretion of water and sodium, thus lowering blood volume in the vascular system.
- Side Effects include dehydration, decreased potassium (hypokalemia) that may cause arrhythmias, loss of energy, and intolerance to physical therapy, and getting rid of potassium while getting rid of sodium.
- Types include thiazide, loop, and potassium-sparing diuretics.
- Example thiazide: Hydrochlorothiazide and Chlorthalidone
- Example loop diuretics: Furosemide (Lasix), Bumetanide, Torsemide, Ethacrynic acid
- Example potassium-sparing diuretics include Spironolactone and Triamterene, and diuretics can cause kidney stones.
- Adverse Effects include fluid depletion, electrolyte imbalance (hyponatremia and hypokalemia), hypotension, impaired glucose and lipid metabolism, fatigue, frequent urination, and problems with blood pressure.
Sympatholytic Drugs (Beta Blockers)
- Drugs that interfere with sympathetic discharge. Examples include beta blockers, alpha blockers, presynaptic adrenergic inhibitors, and centrally acting agonists.
- Beta blockers decrease heart rate (HR) and myocardial contractility (force of contraction). They reduce hypertension by decreasing cardiac output (CO).
- End in -lol (Carvedilol, Propranolol, Metoprolol)
- Side effects: Non-selective beta blockers block beta-1 and beta-2 receptors; this can cause bronchoconstriction in patients with asthma or other respiratory issues.
- Other side effects include orthostatic hypotension, impaired glucose and lipid metabolism, fatigue, GI disturbances, allergic reactions, and blunted HR response to exercise.
Sympatholytic Drugs (Alpha Blockers)
- Block alpha-1 adrenergic receptors in vascular smooth muscle, decreasing vascular resistance.
- This decreases the pressure and causes vasodilation.
- Examples: Doxazosin (Cardura) and Prazosin (Minipress)
- Side effects: Reflex tachycardia, orthostatic hypotension, potential worsening of cardiac disease or heart failure, especially in those already at risk.
Sympatholytics Presynaptic Adrenergic Inhibitors and Centrally Acting Agents
- These inhibit the release of norepinephrine, decreasing sympathetic nervous system activity, which in turn lowers blood pressure.
- Adverse effects include bradycardia, arrhythmias, drowsiness, and gastrointestinal disturbances (nausea, vomiting, diarrhea).
- Centrally acting agents (e.g., Clonidine, Catapres) inhibit sympathetic discharge from the brainstem, causing lower blood pressure.
- Side effects include dry mouth, dizziness, and sedation.
Vasodilators
- Drugs that dilate peripheral blood vessels, decreasing peripheral vascular resistance and thus lowering blood pressure.
- Side Effects include reflex tachycardia, dizziness, orthostatic hypotension, weakness, nausea, fluid retention, and headaches.
Renin-Angiotensin System (RAS) Inhibitors
- These drugs interfere with the RAS, lowering blood pressure through vasodilation.
- ACE inhibitors (-pril): Examples: Capoten (Captopril), Zestril (Lisinopril)
- Angiotensin II receptor blockers (ARBs) (-sartan): Examples : Cozaar (Losartan), Avapro (Irbesartan)
- Direct renin inhibitors: Aliskiren -Adverse effects: Common side effects include cough, angioedema, and hyperkalemia. ARBs may also decrease risk of angioedema compared to ACE inhibitors.
Calcium Channel Blockers
- Block calcium entry into vascular smooth muscle cells, causing vasodilation, thus lowering blood pressure.
- Side effects: Excessive vasodilation (swelling in feet/ankles), orthostatic hypotension. Abnormalities in heart rate such as slow or fast beating.
- Examples: Amlodipine (Norvasc), Diltiazem (Cardizem), Verapamil (Calan) , Nifedipine (Procardia)
Stages of Hypertension
- A table of categories defines different blood pressure levels (normal, elevated, stage 1 hypertension, and stage 2 hypertension) based on systolic and diastolic measurements.
Selecting Drugs for Hypertension
- Initial drug choice for stage 1 hypertension is often a thiazide diuretic, calcium channel blocker, ACE inhibitor or ARB. Some physicians favor using two "first-line drugs."
- Stage 2 hypertension is usually treated with a combination of these drugs.
Treatment of Angina Pectoris
- Angina pectoris is chest pain during ischemic heart disease.
- This is due to insufficient oxygen supply to the heart muscle (myocardium) at that time.
- Factors causing angina include insufficient oxygen delivered to the myocardium to meet demands, or imbalance between oxygen demand and oxygen delivery. Lactic acid build-up also causes symptoms.
Drugs for Angina Pectoris
- Three classes of drugs: organic nitrates, beta blockers, and calcium channel blockers
Organic Nitrates
- Convert to nitric oxide, causing vasodilation in vascular smooth muscle cells, and thus decreasing blood returning to the heart (preload) and resistance against which the heart pumps blood (afterload).
- This decreases work of the heart and reduces myocardial oxygen demand.
- Examples: Nitroglycerin, isosorbide dinitrate, isosorbide mononitrate.
- Side Effects: Headache, dizziness, orthostatic hypotension.
Beta Blockers
- Decrease heart rate and contractility which reduces workload on the heart
- Adverse Effects: Similar to those for hypertension. Also possible increase in arrhythmias
- Prophylactic administration prevents onset of anginal attacks.
Calcium Channel Blockers
- These reduce blood supply to the heart to reduce myocardial oxygen demand
- Examples: Amlodipine, Diltiazem, Verapamil, Nifedipine
Other Considerations
- Anticoagulants are used during angina situations that may result in blood clot formation
- Stable angina is angina that is triggered by physical exertion
- Variant angina is a result of a spasm in a coronary artery.
- Unstable angina is more severe and may be a precursor to a heart attack.
Treatment of Cardiac Arrhythmias
- Arrhythmia is any deviation from normal cardiac rhythm.
- This disruption can come from abnormalities in automatic rhythm generation (SA and AV nodes)
- Abnormalities in conduction within the myocardium
- Simultaneous abnormalities in both rhythm generation and conduction.
- Causes include electrolyte imbalances, metabolic issues, drug toxicity, autonomic factors, heart disease, or genetic factors
- Treatment involves several classes of drugs.
Antiarrhythmics (Class I)
- Sodium channel blockers. These drugs bind to the sodium channels in various tissues, including cardiac tissue reducing excitability of the SA and AV nodes, thus normalizing cardiac rate of firing.
- Side effects include increasing rhythm disturbances (proarrhythmic effect), dizziness, visual disturbances, GI issues (nausea, vomiting, diarrhea).
Antiarrhythmics (Class II)
- Beta blockers. Decrease excitatory effects of the sympathetic nervous system and slow and control heart rate.
- May cause bronchoconstriction in COPD/asthma patients. Excessive slowing of heart rate can increase arrhythmias.
Antiarrhythmics (Class III)
- Prolong repolarization of cardiac cells. These agents lengthen the time between heartbeats and help keep heart rate stabilized.
- Side effects: initial increase in arrhythmias, pulmonary toxicity, thyroid issues, neurotoxicity, and liver damage
Antiarrhythmics (Class IV)
- Calcium channel blockers. Block calcium entry into cardiac and smooth muscles reducing the excitability/conduction of the tissues, slowing SA node discharge and conduction velocity through the AV node.
- These are extremely helpful for treating a-fib. Often useful against rate control.
- Side Effects: Excessive bradycardia, dizziness, constipation are possible side effects.
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Description
This quiz focuses on antihypertensive drugs, their effects on conditions such as angina pectoris and cardiac arrhythmias. Participants will explore the mechanisms, indications, and side effects of these medications, and how they influence patient therapy. Test your knowledge on blood pressure regulation and the types of hypertension.
