Questions and Answers
What is the primary effect of Captopril as it relates to the renin-angiotensin system?
Which statement correctly describes the role of Beta-blockers in treating hypertension?
What is the main action of Aliskiren in the context of hypertension management?
Beta-blockers exert their antihypertensive effect primarily through which mechanism?
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Which of the following is a likely consequence of increased aldosterone secretion?
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What potential complication can arise from using Beta-blockers in hypertensive patients?
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Which of the following drugs acts by preventing the breakdown of cGMP?
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What is the primary mechanism of action for nitrates in terms of vasodilation?
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Which of these drugs directly opens potassium channels in vascular smooth muscle cells, leading to vasodilation?
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Which of the following is a characteristic of cGMP-mediated vasodilation, compared to cAMP-mediated vasodilation?
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Which of the following statements is TRUE regarding directly acting vasodilators?
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What is the common mechanism of action for drugs that increase cAMP levels in vascular tissue?
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What is the primary mechanism by which calcium channel blockers (CCBs) reduce blood pressure?
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Which of the following are examples of dihydropyridine calcium channel blockers?
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Which of the following are common side effects associated with the use of calcium channel blockers?
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Which of the following is NOT a primary pharmacological strategy to reduce blood pressure?
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What is the mechanism of action of directly acting vasodilators?
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Which of the following drugs acts as a directly acting vasodilator, often used in the treatment of pulmonary hypertension?
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Which of the following describes the mechanism of action of nitrates in reducing blood pressure?
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What is the primary mechanism by which phosphodiesterase inhibitors, like milrinone, reduce blood pressure?
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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.