Antihypertensive

Questions and Answers

What is the primary effect of Captopril as it relates to the renin-angiotensin system?

ACE inhibition leading to vasodilation (correct)

Increase in angiotensin II production

Inhibition of aldosterone secretion

Stimulating renin release

Which statement correctly describes the role of Beta-blockers in treating hypertension?

They only affect beta-2 receptors in vascular smooth muscle.

They are first-line treatments in all hypertensive patients.

Their use is contraindicated in individuals with asthma and diabetes. (correct)

They act as vasodilators by directly relaxing blood vessels.

What is the main action of Aliskiren in the context of hypertension management?

Promotion of vasoconstriction

Inhibition of ACE activity

Direct renin inhibition (correct)

Stimulation of aldosterone secretion

Beta-blockers exert their antihypertensive effect primarily through which mechanism?

Antagonism of both β1 and β2 adrenergic receptors Signup and view all the answers

Which of the following is a likely consequence of increased aldosterone secretion?

Retention of water and sodium leading to hypertension Signup and view all the answers

What potential complication can arise from using Beta-blockers in hypertensive patients?

Bronchospasm in asthmatic patients Signup and view all the answers

Which of the following drugs acts by preventing the breakdown of cGMP?

Sildenafil Signup and view all the answers

What is the primary mechanism of action for nitrates in terms of vasodilation?

Increase in cGMP levels Signup and view all the answers

Which of these drugs directly opens potassium channels in vascular smooth muscle cells, leading to vasodilation?

Minoxidil Signup and view all the answers

Which of the following is a characteristic of cGMP-mediated vasodilation, compared to cAMP-mediated vasodilation?

cGMP-mediated vasodilation is primarily triggered by nitric oxide (NO) Signup and view all the answers

Which of the following statements is TRUE regarding directly acting vasodilators?

They are primarily used for treating hypertensive emergencies Signup and view all the answers

What is the common mechanism of action for drugs that increase cAMP levels in vascular tissue?

Activation of adenylate cyclase Signup and view all the answers

What is the primary mechanism by which calcium channel blockers (CCBs) reduce blood pressure?

Reducing calcium-dependent contraction in smooth muscle Signup and view all the answers

Which of the following are examples of dihydropyridine calcium channel blockers?

Nifedipine, Amlodipine, and Felodipine Signup and view all the answers

Which of the following are common side effects associated with the use of calcium channel blockers?

Oedema, flushing, and postural hypotension Signup and view all the answers

Which of the following is NOT a primary pharmacological strategy to reduce blood pressure?

Increasing cardiac output (CO) Signup and view all the answers

What is the mechanism of action of directly acting vasodilators?

They directly dilate blood vessels, independent of other pathways Signup and view all the answers

Which of the following drugs acts as a directly acting vasodilator, often used in the treatment of pulmonary hypertension?

Hydralazine Signup and view all the answers

Which of the following describes the mechanism of action of nitrates in reducing blood pressure?

They stimulate the production of nitric oxide (NO), which activates guanylate cyclase, leading to increased cGMP levels Signup and view all the answers

What is the primary mechanism by which phosphodiesterase inhibitors, like milrinone, reduce blood pressure?

They inhibit the enzyme phosphodiesterase, leading to increased levels of cAMP Signup and view all the answers

Study Notes

Pharmacological Strategies for Hypertension

Blood pressure (BP) = cardiac output (CO) x peripheral vascular resistance (PVR)
CO = heart rate (HR) x stroke volume (SV)
Main strategies to reduce BP:
- Reduce PVR: dilate blood vessels
- Reduce CO: decrease HR, contractile force, or blood volume

Calcium Channel Blockers (CCBs)

L-type calcium channel blockers
Reduce Ca2+-dependent contraction in smooth muscle
Dihydropyridines (e.g., nifedipine, amlodipine) selective for vascular muscle
Used to prevent vasospasm

Alpha-Blockers

Doxazosin, prazosin
a1 adrenoreceptor activation causes vasoconstriction (Gq)
a1 blockers vasodilatory: ↓PVR
Effective at reducing BP and very well tolerated; side effects: oedema, postural hypotension, dry mouth

Directly Acting Vasodilators

Nitrates (e.g., glyceryl trinitrate, nitroprusside): NO → ↑cGMP
Phosphodiesterase inhibitors (e.g., sildenafil): prevent cGMP breakdown
Minoxidil: opens K+ATP channels and hyperpolarizes vascular smooth muscle cells
Hydralazine: MoA unclear; multiple mechanisms?

ACE Inhibitors and Angiotensin Receptor Blockers

Angiotensin converting enzyme (ACE) inhibitors
Angiotensin receptor blockers
Reduce angiotensin II-mediated vasoconstriction and aldosterone secretion

Beta-Blockers

β1 & β2 antagonists
Second line hypertension treatment in UK
Contraindicated in hypertensive individuals with asthma / COPD, diabetes, some arrhythmias
b1 / b2 receptor antagonism: negative chrono- and inotropic in heart; b2 receptor antagonism: vascular smooth muscle constriction

Side Effects of Vasodilators

Common side effects of CCBs, alpha blockers, directly acting vasodilators:
- Oedema
- Flushing
- Postural hypotension (dizziness)
- Fatigue
- Reflex tachycardia (baroreceptor response)
- Headache

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Description

This quiz covers the different types of antihypertensive medications, including DHPs and non-DHPs, alpha-blockers, and their effects on blood pressure and cardiac output.