Pharmacology Unit 7: Antihypertensive Drugs
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Questions and Answers

What is the primary function of the blood pressure in the human body?

  • To regulate body temperature
  • To maintain continuous blood circulation (correct)
  • To filter waste products from the blood
  • To supply oxygen to the brain

What is measured during blood pressure measurement?

  • The amount of friction the blood encounters as it flows through the blood vessels
  • The pressure in the arteries at the peak of ventricular contraction and relaxation (correct)
  • The volume of blood pumped by each ventricle in one contraction
  • The heart rate and stroke volume

Which of the following is NOT a factor affecting blood pressure?

  • Body temperature (correct)
  • Cardiac output
  • Peripheral resistance
  • Neural factors

What is the equation that relates blood pressure to its contributing factors?

<p>BP = CO x PR (A)</p> Signup and view all the answers

What is the term for the volume of blood pumped by each ventricle in one contraction?

<p>Stroke volume (D)</p> Signup and view all the answers

Which division of the autonomic nervous system has a significant impact on blood pressure?

<p>Sympathetic division (B)</p> Signup and view all the answers

What is the unit of measurement for blood pressure?

<p>Millimeters of mercury (A)</p> Signup and view all the answers

What is the purpose of the right atrium in the context of blood pressure?

<p>To pump deoxygenated blood to the lungs (C)</p> Signup and view all the answers

What is the effect of sympathetic nerves on blood vessels?

<p>Vasoconstriction (A)</p> Signup and view all the answers

What is the function of baroreceptors in large arteries?

<p>To send warning signals in response to blood pressure changes (A)</p> Signup and view all the answers

What is the effect of exercise and stress on blood vessels?

<p>Vasoconstriction in most body parts, except skeletal muscles (C)</p> Signup and view all the answers

What is the role of the kidneys in regulating blood pressure?

<p>To alter blood volume and blood pressure (B)</p> Signup and view all the answers

What is the effect of diuretics on blood pressure?

<p>Decrease blood pressure (A)</p> Signup and view all the answers

What happens when arterial blood pressure falls?

<p>Kidneys retain body water, increasing blood volume and blood pressure (D)</p> Signup and view all the answers

What is the effect of angiotensin II on blood vessels?

<p>Vasoconstriction (B)</p> Signup and view all the answers

What is the effect of heat on blood vessels?

<p>Vasodilation (B)</p> Signup and view all the answers

What is the function of the renin-angiotensin-aldosterone system (RAAS)?

<p>To increase blood pressure (B)</p> Signup and view all the answers

What is the effect of β-blockers on blood pressure?

<p>Decrease blood pressure (B)</p> Signup and view all the answers

What is the effect of epinephrine on the body?

<p>Increases both heart rate and blood pressure (B)</p> Signup and view all the answers

Why should people with hypertension quit smoking?

<p>Smoking increases blood pressure by causing vasoconstriction (B)</p> Signup and view all the answers

What is the effect of alcohol on blood vessels?

<p>Vasodilation (A)</p> Signup and view all the answers

What is the primary mechanism by which diuretics lower blood pressure?

<p>By depleting body sodium stores (C)</p> Signup and view all the answers

Which of the following is a class of antihypertensive drugs that acts on the renin-angiotensin-aldosterone system?

<p>ACE Inhibitors (C)</p> Signup and view all the answers

What is the mechanism of action of thiazide diuretics?

<p>Blocking Na/Cl transporter in the renal distal convoluted tubule (C)</p> Signup and view all the answers

What is the effect of loop diuretics on renal blood flow?

<p>Increased renal blood flow (D)</p> Signup and view all the answers

What is the equation that relates blood pressure to cardiac output and peripheral resistance?

<p>BP = CO x PR (B)</p> Signup and view all the answers

What is the effect of baroreflexes on blood pressure?

<p>Regulate blood pressure through the sympathetic nervous system (B)</p> Signup and view all the answers

What is the primary mechanism by which β-blockers lower blood pressure?

<p>By decreasing heart rate (C)</p> Signup and view all the answers

What is the result of propranolol's negative inotropic and chronotropic effects on the heart?

<p>Decreased cardiac output and heart rate (A)</p> Signup and view all the answers

Why must β-blockers be tapered over a few weeks in patients with hypertension and ischemic heart disease?

<p>To reduce the risk of myocardial infarction and sudden death (D)</p> Signup and view all the answers

What is the therapeutic use of propranolol in addition to hypertension?

<p>Migraine, Hyperthyroidism, Angina pectoris, and Myocardial infarction (D)</p> Signup and view all the answers

What is the receptor specificity of nebivolol?

<p>β1, β2, NO↑ (D)</p> Signup and view all the answers

What is the effect of β-blockers on heart rate during exercise or stress?

<p>Attenuate the expected increase in heart rate (C)</p> Signup and view all the answers

Which of the following β-adrenergic antagonists is a selective β1 receptor blocker?

<p>Atenolol (C)</p> Signup and view all the answers

What is the effect of ACE inhibitors on blood pressure?

<p>Decrease peripheral vascular resistance (B)</p> Signup and view all the answers

What is a rare but potentially life-threatening reaction to ACE inhibitors?

<p>Angioedema (B)</p> Signup and view all the answers

What is the therapeutic use of timolol?

<p>Glaucoma and Hypertension (A)</p> Signup and view all the answers

What is the mechanism of action of ACE inhibitors?

<p>Blocking the enzyme ACE (B)</p> Signup and view all the answers

What is the primary mechanism of action of potassium-sparing diuretics?

<p>Inhibiting epithelial sodium transport at the late distal and collecting ducts (A)</p> Signup and view all the answers

Which of the following diuretics is an aldosterone receptor antagonist?

<p>Spironolactone (C)</p> Signup and view all the answers

What is the primary effect of β-blockers on the cardiovascular system?

<p>Decrease cardiac output (A)</p> Signup and view all the answers

What is the primary mechanism of action of thiazide diuretics?

<p>Blocking Na/Cl transporter in renal distal convoluted tubule (A)</p> Signup and view all the answers

Which of the following β-blockers is a selective blocker of β1-receptors?

<p>Metoprolol (C)</p> Signup and view all the answers

What is the primary effect of nonselective β-blockers on the lungs?

<p>Bronchoconstriction (C)</p> Signup and view all the answers

What is the primary effect of β-blockers on the renin-angiotensin-aldosterone system?

<p>Decrease renin release (A)</p> Signup and view all the answers

What is a common adverse effect of β-blockers?

<p>Bradycardia (D)</p> Signup and view all the answers

Which of the following diuretics is often used in combination with loop diuretics and thiazides?

<p>Amiloride (C)</p> Signup and view all the answers

What is the primary effect of noncardioselective β-blockers on serum lipid patterns?

<p>Decrease high-density lipoprotein cholesterol (D)</p> Signup and view all the answers

Which of the following is a renin inhibitor?

<p>Aliskiren (D)</p> Signup and view all the answers

What is the main effect of calcium channel blockers on blood vessels?

<p>Dilation of arterioles (D)</p> Signup and view all the answers

Which of the following angiotensin II receptor blockers is available in the form of medoxomil?

<p>Azilsartan (C)</p> Signup and view all the answers

What is the common side effect of verapamil?

<p>Constipation (A)</p> Signup and view all the answers

What is the effect of α1-adrenoceptor blockers on blood vessels?

<p>Decreased vasoconstriction (A)</p> Signup and view all the answers

Which of the following drugs is suitable for pregnant women with hypertension?

<p>Labetalol (A)</p> Signup and view all the answers

What is the effect of clonidine on blood pressure?

<p>Decreased sympathetic outflow (D)</p> Signup and view all the answers

What is the common side effect of dihydropyridines?

<p>Peripheral edema (D)</p> Signup and view all the answers

What is the effect of methyldopa on the body?

<p>Decreases sympathetic outflow (C)</p> Signup and view all the answers

Which of the following drugs is used in the treatment of heart failure?

<p>Carvedilol (B)</p> Signup and view all the answers

What is the direction of blood flow in the body?

<p>From the left atrium to the left ventricle and then to the aorta (B)</p> Signup and view all the answers

What is the term for the pressure in the arteries when the ventricles are relaxing?

<p>Diastolic pressure (D)</p> Signup and view all the answers

Which of the following factors increases peripheral resistance?

<p>Increased friction in blood vessels (A)</p> Signup and view all the answers

What happens to blood pressure when the kidneys retain body water?

<p>It increases (D)</p> Signup and view all the answers

What is the equation that relates blood pressure to its contributing factors?

<p>BP = CO x PR (A)</p> Signup and view all the answers

What is the autonomic nervous system division that plays a significant role in blood pressure regulation?

<p>Sympathetic division (D)</p> Signup and view all the answers

What is the effect of angiotensin II on blood vessels?

<p>Vasoconstriction (B)</p> Signup and view all the answers

What is the unit of measurement for blood pressure?

<p>Millimeters of mercury (mm Hg) (A)</p> Signup and view all the answers

What is the role of baroreceptors in large arteries?

<p>To detect changes in blood pressure (A)</p> Signup and view all the answers

What is the term for the amount of blood pumped out of the left ventricle per minute?

<p>Cardiac output (A)</p> Signup and view all the answers

What is the effect of diuretics on blood volume?

<p>Decrease (C)</p> Signup and view all the answers

What is the factor that determines the amount of blood pumped by each ventricle in one contraction?

<p>Stroke volume (A)</p> Signup and view all the answers

What is the effect of sympathetic nervous system on cardiac output?

<p>Increase (D)</p> Signup and view all the answers

What is the role of renin in the renin-angiotensin-aldosterone system?

<p>To convert angiotensinogen to angiotensin I (B)</p> Signup and view all the answers

What is the effect of heat on blood vessels?

<p>Vasodilation (B)</p> Signup and view all the answers

What is the effect of β-blockers on blood pressure?

<p>Decrease (C)</p> Signup and view all the answers

What is the role of the kidneys in regulating blood pressure?

<p>To regulate blood volume (C)</p> Signup and view all the answers

What is the effect of cold on blood vessels?

<p>Vasoconstriction (C)</p> Signup and view all the answers

Which of the following substances increases blood pressure by causing vasoconstriction?

<p>Nicotine (D)</p> Signup and view all the answers

What is the effect of diuretics on stroke volume?

<p>It decreases (A)</p> Signup and view all the answers

Which of the following is a class of antihypertensive drugs that acts on the renin-angiotensin-aldosterone system?

<p>ACE Inhibitors (B)</p> Signup and view all the answers

What is the primary mechanism by which thiazide diuretics lower blood pressure?

<p>By increasing sodium and water excretion (B)</p> Signup and view all the answers

What is the effect of loop diuretics on renal blood flow?

<p>It increases (D)</p> Signup and view all the answers

Which of the following is a mechanism by which baroreflexes regulate blood pressure?

<p>By changing the activity of the sympathetic nervous system (B)</p> Signup and view all the answers

What is the effect of β-blockers on heart rate?

<p>It decreases (D)</p> Signup and view all the answers

What is the effect of vasodilators on peripheral resistance?

<p>It decreases (D)</p> Signup and view all the answers

Which of the following substances causes vasodilation and decreases blood pressure?

<p>Alcohol and Histamine (A)</p> Signup and view all the answers

What is the primary mechanism by which ACE inhibitors lower blood pressure?

<p>By decreasing angiotensin II production (C)</p> Signup and view all the answers

What is the primary function of potassium-sparing diuretics?

<p>Reduce potassium loss in the urine (C)</p> Signup and view all the answers

Which of the following diuretics inhibits epithelial sodium transport at the late distal and collecting ducts?

<p>Amiloride (D)</p> Signup and view all the answers

What is the mechanism of action of β-adrenoceptor blockers?

<p>Decrease cardiac output (A)</p> Signup and view all the answers

Which of the following is a selective blocker of β1-receptors?

<p>Metoprolol (C)</p> Signup and view all the answers

What is the effect of nonselective β-blockers on the lungs?

<p>Bronchoconstriction (C)</p> Signup and view all the answers

What is the primary mechanism of action of thiazide diuretics?

<p>Block Na/Cl transporter in the renal distal convoluted tubule (B)</p> Signup and view all the answers

What is the effect of β-blockers on serum lipid patterns?

<p>Decrease high-density lipoprotein cholesterol and increase triglycerides (B)</p> Signup and view all the answers

Which of the following is an aldosterone receptor antagonist?

<p>Spironolactone (B)</p> Signup and view all the answers

What is the primary effect of β-blockers on the cardiovascular system?

<p>Decrease cardiac output (C)</p> Signup and view all the answers

Which of the following diuretics is often used in combination with loop diuretics and thiazides?

<p>Potassium-sparing diuretics (D)</p> Signup and view all the answers

What is the effect of propranolol on cardiac output, workload, and oxygen consumption?

<p>Decreased (C)</p> Signup and view all the answers

What is the receptor specificity of carvedilol?

<p>α1, β1, β2 (A)</p> Signup and view all the answers

Why should β-blockers be tapered over a few weeks in patients with hypertension and ischemic heart disease?

<p>To prevent both angina and sudden death (D)</p> Signup and view all the answers

What is the effect of ACE inhibitors on angiotensin II?

<p>Inhibition of formation (B)</p> Signup and view all the answers

What is the therapeutic use of esmolol?

<p>Myocardial infarction (B)</p> Signup and view all the answers

What is the receptor specificity of atenolol?

<p>β1 (A)</p> Signup and view all the answers

What is the effect of β-blockers on lipid metabolism?

<p>Increased LDL and decreased HDL (C)</p> Signup and view all the answers

What is the mechanism of action of angiotensin II receptor blockers?

<p>Blockade of AT1 receptors (C)</p> Signup and view all the answers

What is the therapeutic use of nebivolol?

<p>Hypertension (B)</p> Signup and view all the answers

What is the receptor specificity of labetalol?

<p>α1, β1, β2 (C)</p> Signup and view all the answers

What is the mechanism of action of aliskiren?

<p>Directly inhibits renin (A)</p> Signup and view all the answers

Which of the following calcium channel blockers can cause gingival hyperplasia?

<p>Nifedipine (D)</p> Signup and view all the answers

What is the effect of prazosin, doxazosin, and terazosin on peripheral vascular resistance?

<p>Decrease peripheral vascular resistance (B)</p> Signup and view all the answers

Which of the following drugs is used in the treatment of heart failure?

<p>Carvedilol (A)</p> Signup and view all the answers

What is the mechanism of action of clonidine?

<p>Acts centrally as an α2-agonist (A)</p> Signup and view all the answers

Which of the following drugs is a dihydropyridine calcium channel blocker?

<p>Felodipine (C), Nifedipine (D)</p> Signup and view all the answers

What is the effect of α1-adrenoceptor blocking agents on vasoconstriction?

<p>Decrease vasoconstriction (B)</p> Signup and view all the answers

What is the primary mechanism of action of methyldopa?

<p>Converted to methyl norepinephrine centrally to diminish adrenergic outflow (C)</p> Signup and view all the answers

Which of the following drugs is a selective α1-adrenoceptor blocker?

<p>Doxazosin (C), Prazosin (D)</p> Signup and view all the answers

What is a common adverse effect of dihydropyridine calcium channel blockers?

<p>Peripheral edema (C)</p> Signup and view all the answers

Study Notes

Definition of Terms

  • Blood Pressure: The pressure exerted by blood on the inner walls of blood vessels, keeping blood circulating between heartbeats.
    • Measured in mm Hg (millimeters of mercury)
    • Reported as systolic pressure (peak contraction) and diastolic pressure (relaxation)

Hydraulic Equation of Blood Pressure

  • BP = CO x PR
    • Cardiac Output (CO): Amount of blood pumped out of the left ventricle per minute
      • Determined by Stroke Volume (SV) and Heart Rate (HR)
    • Peripheral Resistance (PR): Friction encountered by blood flowing through blood vessels
      • Increased peripheral resistance increases blood pressure

Factors Affecting Blood Pressure

  • Neural Factors: Autonomic Nervous System
    • Parasympathetic Division: Little or no effect on blood pressure
    • Sympathetic Nerves: Cause vasoconstriction, increasing blood pressure
    • B-blockers: Adrenergic antagonists that lower blood pressure
  • Renal Factors: The Kidneys
    • Kidneys regulate arterial blood pressure by altering blood volume
    • Diuretics: Stimulate kidneys to remove water from blood, decreasing blood volume and pressure
  • Temperature
    • Cold: Vasoconstricting effect
    • Heat: Vasodilating effect
  • Chemical Substances
    • Epinephrine: Increases heart rate and blood pressure
    • Nicotine: Causes vasoconstriction, increasing blood pressure
    • Alcohol & Histamine: Cause vasodilation, decreasing blood pressure
  • Diet
    • Low in salt, saturated fats, and cholesterol: Helps prevent hypertension
    • Diuretics: Affect stroke volume
    • B-blockers: Affect heart rate
    • Vasodilators: Affect peripheral resistance

Mechanisms of Controlling Blood Pressure

  • Hydraulic Equation of Blood Pressure: BP = CO x PR
  • Cardiac Output (CO) and Peripheral Resistance (PR): Controlled by overlapping mechanisms:
    • Baroreflexes
    • Renin-Angiotensin-Aldosterone System (RAAS)

Baroreflex

  • Acts by changing sympathetic nervous system activity
  • Rapid, moment-to-moment regulation of blood pressure

Renin-Angiotensin-Aldosterone System (RAAS)

  • Stimulates renin release from kidneys
  • Increases sodium and water retention, blood volume, and blood pressure

Different Classes of Antihypertensive Drugs

  • Diuretics
  • β-Adrenoceptor Blockers
  • ACE (Angiotensin Converting Enzyme) Inhibitors
  • Angiotensin II Receptor Blockers (ARB)
  • Renin Inhibitor
  • Calcium Channel Blockers
  • α-Adrenoceptor Blocking Agents
  • α-/β-Adrenoceptor Blocking Agents
  • Centrally Acting Adrenergic Drugs
  • Vasodilators

Diuretics

  • Function: Lower blood pressure by depleting body sodium stores
  • Mechanism: Act on stroke volume
  • Classes:
    • Thiazide Diuretics
    • Loop Diuretics
    • Potassium-Sparing Diuretics

β-Adrenoceptor Blockers

  • Function: Reduce blood pressure by decreasing cardiac output
  • Mechanism: Block β1- and β2-receptors
  • Effects:
    • Decrease heart rate
    • Decrease renin release
    • Reduce blood pressure by inhibiting renin-angiotensin-aldosterone system
  • Adverse Effects:
    • Bradycardia
    • Hypotension
    • CNS side effects (fatigue, lethargy, insomnia)
    • Decreased libido and erectile dysfunction
  • Alterations in Serum Lipid Patterns: Noncardioselective β-blockers may disturb lipid metabolism

ACE (Angiotensin Converting Enzyme) Inhibitors

  • Action: Lower blood pressure by reducing peripheral vascular resistance
  • Mechanism: Block ACE, reducing angiotensin II formation
  • Adverse Effects:
    • Dry cough
    • Rash
    • Fever
    • Altered taste
    • Hypotension
    • Hyperkalemia
  • Angioedema: Rare but potentially life-threatening reaction

Angiotensin II Receptor Blockers (ARB)

  • Action: Lower blood pressure by reducing peripheral vascular resistance
  • Mechanism: Block AT1 receptors, decreasing angiotensin II activation
  • Adverse Effects: Similar to ACE inhibitors, but with reduced risk of cough and angioedema

Renin Inhibitor

  • Action: Directly inhibits renin, reducing angiotensin II formation
  • Mechanism: Acts earlier in the renin-angiotensin-aldosterone system than ACE inhibitors or ARBs
  • Adverse Effects: Diarrhea, cough, and angioedema (less frequent than ACE inhibitors)

Calcium Channel Blockers

  • Action: Lower blood pressure by relaxing vascular smooth muscle
  • Mechanism: Block L-type calcium channels in the heart and smooth muscle
  • Adverse Effects:
    • Dizziness
    • Headache
    • Fatigue
    • Peripheral edema
    • Gingival hyperplasia (dihydropyridines)

α-Adrenoceptor Blocking Agents

  • Action: Lower blood pressure by blocking α1-adrenoceptors

  • Mechanism: Relax both arterial and venous smooth muscle

  • Adverse Effects:

    • Dizziness
    • Headache
    • Fatigue
    • Orthostatic hypotension### Inhibition of α1 Binding

  • Inhibition of α1 binding leads to decreased vasoconstriction, decreased peripheral resistance (PR), and decreased blood pressure (BP)

  • α1 binding is blocked by prazosin, doxazosin, or terazosin, which prevents norepinephrine (NE) and epinephrine (E) binding

Adverse Effects

  • Reflex tachycardia and postural hypotension often occur at the onset of treatment and with dose increases, requiring slow titration of the drug in divided doses
  • Orthostatic hypotension leads to low blood pressure and lightheadedness upon standing up

α-/β-Adrenoceptor Blocking Agents

  • Labetalol and Carvedilol block α1, β1, and β2 receptors
  • Not suitable for patients with asthma
  • Carvedilol is an effective antihypertensive, used in the treatment of heart failure
  • Labetalol is used in the management of gestational hypertension and hypertensive emergencies, and is suitable for pregnant women
  • Carvedilol, Metoprolol Succinate, and Bisoprolol have been shown to reduce morbidity and mortality associated with heart failure

Centrally Acting Adrenergic Drugs

  • Clonidine acts centrally as an α2-agonist, decreasing sympathetic outflow to the periphery
  • Clonidine is used for hypertension complicated by renal disease
  • Methyldopa is converted to methyl norepinephrine centrally, diminishing adrenergic outflow from the CNS
  • Methyldopa is commonly associated with sedation and drowsiness, and has limited use due to adverse effects and the need for multiple daily doses
  • Methyldopa is mainly used for hypertension in pregnancy due to its safety record

Vasodilators

  • Vasodilators act by producing relaxation of vascular smooth muscle, primarily in arteries and arterioles

Additional Information

  • Hydralazine and Minoxidil are not used as primary drugs to treat hypertension
  • Hydralazine is administered with a β-blocker and a diuretic
  • Minoxidil is used to treat hypertrochosis (growth of body hair) and is used topically for male pattern baldness

Definition of Terms

  • Blood Pressure: The pressure exerted by blood on the inner walls of blood vessels, keeping blood circulating between heartbeats.
    • Measured in mm Hg (millimeters of mercury)
    • Reported as systolic pressure (peak contraction) and diastolic pressure (relaxation)

Hydraulic Equation of Blood Pressure

  • BP = CO x PR
    • Cardiac Output (CO): Amount of blood pumped out of the left ventricle per minute
      • Determined by Stroke Volume (SV) and Heart Rate (HR)
    • Peripheral Resistance (PR): Friction encountered by blood flowing through blood vessels
      • Increased peripheral resistance increases blood pressure

Factors Affecting Blood Pressure

  • Neural Factors: Autonomic Nervous System
    • Parasympathetic Division: Little or no effect on blood pressure
    • Sympathetic Nerves: Cause vasoconstriction, increasing blood pressure
    • B-blockers: Adrenergic antagonists that lower blood pressure
  • Renal Factors: The Kidneys
    • Kidneys regulate arterial blood pressure by altering blood volume
    • Diuretics: Stimulate kidneys to remove water from blood, decreasing blood volume and pressure
  • Temperature
    • Cold: Vasoconstricting effect
    • Heat: Vasodilating effect
  • Chemical Substances
    • Epinephrine: Increases heart rate and blood pressure
    • Nicotine: Causes vasoconstriction, increasing blood pressure
    • Alcohol & Histamine: Cause vasodilation, decreasing blood pressure
  • Diet
    • Low in salt, saturated fats, and cholesterol: Helps prevent hypertension
    • Diuretics: Affect stroke volume
    • B-blockers: Affect heart rate
    • Vasodilators: Affect peripheral resistance

Mechanisms of Controlling Blood Pressure

  • Hydraulic Equation of Blood Pressure: BP = CO x PR
  • Cardiac Output (CO) and Peripheral Resistance (PR): Controlled by overlapping mechanisms:
    • Baroreflexes
    • Renin-Angiotensin-Aldosterone System (RAAS)

Baroreflex

  • Acts by changing sympathetic nervous system activity
  • Rapid, moment-to-moment regulation of blood pressure

Renin-Angiotensin-Aldosterone System (RAAS)

  • Stimulates renin release from kidneys
  • Increases sodium and water retention, blood volume, and blood pressure

Different Classes of Antihypertensive Drugs

  • Diuretics
  • β-Adrenoceptor Blockers
  • ACE (Angiotensin Converting Enzyme) Inhibitors
  • Angiotensin II Receptor Blockers (ARB)
  • Renin Inhibitor
  • Calcium Channel Blockers
  • α-Adrenoceptor Blocking Agents
  • α-/β-Adrenoceptor Blocking Agents
  • Centrally Acting Adrenergic Drugs
  • Vasodilators

Diuretics

  • Function: Lower blood pressure by depleting body sodium stores
  • Mechanism: Act on stroke volume
  • Classes:
    • Thiazide Diuretics
    • Loop Diuretics
    • Potassium-Sparing Diuretics

β-Adrenoceptor Blockers

  • Function: Reduce blood pressure by decreasing cardiac output
  • Mechanism: Block β1- and β2-receptors
  • Effects:
    • Decrease heart rate
    • Decrease renin release
    • Reduce blood pressure by inhibiting renin-angiotensin-aldosterone system
  • Adverse Effects:
    • Bradycardia
    • Hypotension
    • CNS side effects (fatigue, lethargy, insomnia)
    • Decreased libido and erectile dysfunction
  • Alterations in Serum Lipid Patterns: Noncardioselective β-blockers may disturb lipid metabolism

ACE (Angiotensin Converting Enzyme) Inhibitors

  • Action: Lower blood pressure by reducing peripheral vascular resistance
  • Mechanism: Block ACE, reducing angiotensin II formation
  • Adverse Effects:
    • Dry cough
    • Rash
    • Fever
    • Altered taste
    • Hypotension
    • Hyperkalemia
  • Angioedema: Rare but potentially life-threatening reaction

Angiotensin II Receptor Blockers (ARB)

  • Action: Lower blood pressure by reducing peripheral vascular resistance
  • Mechanism: Block AT1 receptors, decreasing angiotensin II activation
  • Adverse Effects: Similar to ACE inhibitors, but with reduced risk of cough and angioedema

Renin Inhibitor

  • Action: Directly inhibits renin, reducing angiotensin II formation
  • Mechanism: Acts earlier in the renin-angiotensin-aldosterone system than ACE inhibitors or ARBs
  • Adverse Effects: Diarrhea, cough, and angioedema (less frequent than ACE inhibitors)

Calcium Channel Blockers

  • Action: Lower blood pressure by relaxing vascular smooth muscle
  • Mechanism: Block L-type calcium channels in the heart and smooth muscle
  • Adverse Effects:
    • Dizziness
    • Headache
    • Fatigue
    • Peripheral edema
    • Gingival hyperplasia (dihydropyridines)

α-Adrenoceptor Blocking Agents

  • Action: Lower blood pressure by blocking α1-adrenoceptors

  • Mechanism: Relax both arterial and venous smooth muscle

  • Adverse Effects:

    • Dizziness
    • Headache
    • Fatigue
    • Orthostatic hypotension### Inhibition of α1 Binding

  • Inhibition of α1 binding leads to decreased vasoconstriction, decreased peripheral resistance (PR), and decreased blood pressure (BP)

  • α1 binding is blocked by prazosin, doxazosin, or terazosin, which prevents norepinephrine (NE) and epinephrine (E) binding

Adverse Effects

  • Reflex tachycardia and postural hypotension often occur at the onset of treatment and with dose increases, requiring slow titration of the drug in divided doses
  • Orthostatic hypotension leads to low blood pressure and lightheadedness upon standing up

α-/β-Adrenoceptor Blocking Agents

  • Labetalol and Carvedilol block α1, β1, and β2 receptors
  • Not suitable for patients with asthma
  • Carvedilol is an effective antihypertensive, used in the treatment of heart failure
  • Labetalol is used in the management of gestational hypertension and hypertensive emergencies, and is suitable for pregnant women
  • Carvedilol, Metoprolol Succinate, and Bisoprolol have been shown to reduce morbidity and mortality associated with heart failure

Centrally Acting Adrenergic Drugs

  • Clonidine acts centrally as an α2-agonist, decreasing sympathetic outflow to the periphery
  • Clonidine is used for hypertension complicated by renal disease
  • Methyldopa is converted to methyl norepinephrine centrally, diminishing adrenergic outflow from the CNS
  • Methyldopa is commonly associated with sedation and drowsiness, and has limited use due to adverse effects and the need for multiple daily doses
  • Methyldopa is mainly used for hypertension in pregnancy due to its safety record

Vasodilators

  • Vasodilators act by producing relaxation of vascular smooth muscle, primarily in arteries and arterioles

Additional Information

  • Hydralazine and Minoxidil are not used as primary drugs to treat hypertension
  • Hydralazine is administered with a β-blocker and a diuretic
  • Minoxidil is used to treat hypertrochosis (growth of body hair) and is used topically for male pattern baldness

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Description

This quiz covers the basics of antihypertensive drugs, including the definition of blood pressure, measuring blood pressure, and systolic pressure.

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