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Questions and Answers
What is the primary therapeutic use of nifedipine?
What is the primary therapeutic use of nifedipine?
Which of the following is a key difference between immediate-release (IR) and sustained-release (SR) nifedipine?
Which of the following is a key difference between immediate-release (IR) and sustained-release (SR) nifedipine?
What adverse effect is NOT typically associated with nifedipine?
What adverse effect is NOT typically associated with nifedipine?
Combining nifedipine with which type of medication can help prevent reflex tachycardia?
Combining nifedipine with which type of medication can help prevent reflex tachycardia?
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Which of the following statements regarding nifedipine's use in angina is accurate?
Which of the following statements regarding nifedipine's use in angina is accurate?
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What is the primary therapeutic use of calcium channel blockers?
What is the primary therapeutic use of calcium channel blockers?
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How do calcium channel blockers influence vascular smooth muscle function?
How do calcium channel blockers influence vascular smooth muscle function?
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What effect does calcium channel blockade have on the heart's sinoatrial node?
What effect does calcium channel blockade have on the heart's sinoatrial node?
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Which of the following statements about calcium channels is true?
Which of the following statements about calcium channels is true?
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Calcium channel blockers do NOT have a significant effect on which of the following?
Calcium channel blockers do NOT have a significant effect on which of the following?
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What mechanism do calcium channel blockers and β1-adrenergic receptors share in the heart?
What mechanism do calcium channel blockers and β1-adrenergic receptors share in the heart?
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Which type of calcium channel blockers does NOT include dihydropyridines?
Which type of calcium channel blockers does NOT include dihydropyridines?
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What adverse effect has been debated regarding the use of calcium channel blockers?
What adverse effect has been debated regarding the use of calcium channel blockers?
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What is the primary action of norepinephrine in relation to heart function?
What is the primary action of norepinephrine in relation to heart function?
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What is the main cardiovascular effect of verapamil on patients?
What is the main cardiovascular effect of verapamil on patients?
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Why must verapamil doses be reduced in patients with hepatic impairment?
Why must verapamil doses be reduced in patients with hepatic impairment?
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Which condition is verapamil widely used to treat?
Which condition is verapamil widely used to treat?
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What is a common adverse effect associated with both verapamil and diltiazem?
What is a common adverse effect associated with both verapamil and diltiazem?
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What type of drug interaction should be monitored closely when verapamil and digoxin are used together?
What type of drug interaction should be monitored closely when verapamil and digoxin are used together?
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How does grapefruit juice affect drug metabolism?
How does grapefruit juice affect drug metabolism?
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What is the primary route of elimination for diltiazem?
What is the primary route of elimination for diltiazem?
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In which patient population should verapamil be used with caution?
In which patient population should verapamil be used with caution?
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What effect does diltiazem have on the gastrointestinal system compared to verapamil?
What effect does diltiazem have on the gastrointestinal system compared to verapamil?
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What is the primary therapeutic indication for both verapamil and diltiazem?
What is the primary therapeutic indication for both verapamil and diltiazem?
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Which patient population requires a careful discussion of the risks and benefits when considering calcium channel blocker therapy?
Which patient population requires a careful discussion of the risks and benefits when considering calcium channel blocker therapy?
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Which side effect is associated specifically with the use of nifedipine?
Which side effect is associated specifically with the use of nifedipine?
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What is a key difference between nifedipine and verapamil regarding their effects on the heart?
What is a key difference between nifedipine and verapamil regarding their effects on the heart?
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What monitoring is generally not required for patients starting therapy with verapamil or diltiazem?
What monitoring is generally not required for patients starting therapy with verapamil or diltiazem?
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In which group of patients have calcium channel blockers been associated with chronic eczematous eruptions?
In which group of patients have calcium channel blockers been associated with chronic eczematous eruptions?
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What effect does nifedipine have on blood pressure and heart rate?
What effect does nifedipine have on blood pressure and heart rate?
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Which condition is a contraindication for the use of verapamil and diltiazem?
Which condition is a contraindication for the use of verapamil and diltiazem?
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Which of the following statements regarding diltiazem is true?
Which of the following statements regarding diltiazem is true?
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What should be initiated with low doses and adjusted carefully to minimize adverse effects?
What should be initiated with low doses and adjusted carefully to minimize adverse effects?
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What regulates the excitability of AV nodal cells?
What regulates the excitability of AV nodal cells?
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What is the result of calcium channel blockade in the AV node?
What is the result of calcium channel blockade in the AV node?
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Which type of adrenergic receptor enhances calcium influx when activated?
Which type of adrenergic receptor enhances calcium influx when activated?
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Which drug is the prototype for the dihydropyridine class of calcium channel blockers?
Which drug is the prototype for the dihydropyridine class of calcium channel blockers?
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What effect does verapamil have on the SA node?
What effect does verapamil have on the SA node?
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What is one of the primary actions of nondihydropyridine calcium channel blockers like verapamil?
What is one of the primary actions of nondihydropyridine calcium channel blockers like verapamil?
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How do calcium channel blockers and β blockers affect cardiac function?
How do calcium channel blockers and β blockers affect cardiac function?
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What physiological change occurs due to baroreceptor reflex activation following verapamil-induced blood pressure lowering?
What physiological change occurs due to baroreceptor reflex activation following verapamil-induced blood pressure lowering?
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What dictates the direct effect on cardiac function in different myocardial cells when calcium channels are activated?
What dictates the direct effect on cardiac function in different myocardial cells when calcium channels are activated?
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Which of the following is NOT an effect of blocking calcium channels with verapamil?
Which of the following is NOT an effect of blocking calcium channels with verapamil?
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What is one of the reasons nifedipine is preferred over verapamil for certain patients?
What is one of the reasons nifedipine is preferred over verapamil for certain patients?
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What type of formulation of nifedipine is contraindicated for use in hypertensive emergencies?
What type of formulation of nifedipine is contraindicated for use in hypertensive emergencies?
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How can peripheral edema, an adverse effect of nifedipine, be effectively managed?
How can peripheral edema, an adverse effect of nifedipine, be effectively managed?
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Which of the following therapeutic areas does nifedipine primarily target?
Which of the following therapeutic areas does nifedipine primarily target?
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What potential risk is associated with immediate-release (IR) nifedipine in patients with myocardial infarction?
What potential risk is associated with immediate-release (IR) nifedipine in patients with myocardial infarction?
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What effect does blocking calcium channels have on vascular smooth muscle?
What effect does blocking calcium channels have on vascular smooth muscle?
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How do calcium channel blockers impact heart rate?
How do calcium channel blockers impact heart rate?
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Which type of calcium channel blocker is primarily linked to an increase in force of cardiac contraction?
Which type of calcium channel blocker is primarily linked to an increase in force of cardiac contraction?
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What physiological role does calcium influx serve in the sinoatrial (SA) node?
What physiological role does calcium influx serve in the sinoatrial (SA) node?
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What is a critical consequence of calcium channel blockade in the myocardium?
What is a critical consequence of calcium channel blockade in the myocardium?
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In which of the following does calcium channel blockade primarily lead to vasodilation?
In which of the following does calcium channel blockade primarily lead to vasodilation?
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What characterizes the action of calcium channel blockers on veins?
What characterizes the action of calcium channel blockers on veins?
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Which condition presents a controversial safety concern when using calcium channel blockers?
Which condition presents a controversial safety concern when using calcium channel blockers?
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In which patient population is close monitoring advised when using diltiazem concurrently with digoxin?
In which patient population is close monitoring advised when using diltiazem concurrently with digoxin?
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What is the primary reason nifedipine cannot be used to treat cardiac dysrhythmias?
What is the primary reason nifedipine cannot be used to treat cardiac dysrhythmias?
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Which condition should be a contraindication for the use of verapamil?
Which condition should be a contraindication for the use of verapamil?
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What adverse effect is uniquely associated with the immediate-release formulation of nifedipine?
What adverse effect is uniquely associated with the immediate-release formulation of nifedipine?
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Which of the following is a common adverse effect when using both nifedipine and verapamil?
Which of the following is a common adverse effect when using both nifedipine and verapamil?
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Which of these statements regarding calcium channel blockers in breastfeeding women is correct?
Which of these statements regarding calcium channel blockers in breastfeeding women is correct?
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How does the hemodynamic effect of nifedipine primarily manifest?
How does the hemodynamic effect of nifedipine primarily manifest?
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What is the preferred dosing strategy to minimize adverse effects when starting treatment with calcium channel blockers?
What is the preferred dosing strategy to minimize adverse effects when starting treatment with calcium channel blockers?
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In older adults, calcium channel blockers are associated with which specific skin condition?
In older adults, calcium channel blockers are associated with which specific skin condition?
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What factor should be monitored in patients taking diltiazem and digoxin in conjunction?
What factor should be monitored in patients taking diltiazem and digoxin in conjunction?
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What is the primary effect of verapamil on the cardiovascular system?
What is the primary effect of verapamil on the cardiovascular system?
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How does verapamil affect cardiac conduction in patients with atrial flutter?
How does verapamil affect cardiac conduction in patients with atrial flutter?
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What is a significant pharmacokinetic characteristic of oral verapamil administration?
What is a significant pharmacokinetic characteristic of oral verapamil administration?
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What common side effect should patients anticipate when taking verapamil?
What common side effect should patients anticipate when taking verapamil?
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What is the effect of combining digoxin with verapamil?
What is the effect of combining digoxin with verapamil?
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In which condition should verapamil be used with special caution?
In which condition should verapamil be used with special caution?
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What is the approximate bioavailability of oral diltiazem after first-pass metabolism?
What is the approximate bioavailability of oral diltiazem after first-pass metabolism?
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Which of the following statements is true regarding the adverse effects of diltiazem compared to verapamil?
Which of the following statements is true regarding the adverse effects of diltiazem compared to verapamil?
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What is a key factor that affects the use of verapamil in patients with liver disease?
What is a key factor that affects the use of verapamil in patients with liver disease?
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What cardiovascular effect does verapamil primarily have when treating essential hypertension?
What cardiovascular effect does verapamil primarily have when treating essential hypertension?
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What is the main effect of calcium channel blockade on the atrioventricular node?
What is the main effect of calcium channel blockade on the atrioventricular node?
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How does activating cardiac β1-adrenergic receptors affect calcium entry?
How does activating cardiac β1-adrenergic receptors affect calcium entry?
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What distinguishes dihydropyridines from nondihydropyridines in terms of their action sites?
What distinguishes dihydropyridines from nondihydropyridines in terms of their action sites?
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What is a major hemodynamic effect of verapamil on blood vessels?
What is a major hemodynamic effect of verapamil on blood vessels?
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Which of the following best describes the overall action of calcium channel blockers and β blockers on the heart?
Which of the following best describes the overall action of calcium channel blockers and β blockers on the heart?
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What is the role of cAMP in the context of β1-adrenergic receptor activation?
What is the role of cAMP in the context of β1-adrenergic receptor activation?
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Which of the following medications belongs to the dihydropyridine class of calcium channel blockers?
Which of the following medications belongs to the dihydropyridine class of calcium channel blockers?
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What effect does the baroreceptor reflex have when blood pressure decreases due to verapamil?
What effect does the baroreceptor reflex have when blood pressure decreases due to verapamil?
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Which of the following actions is a result of calcium entry in SA nodal cells?
Which of the following actions is a result of calcium entry in SA nodal cells?
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What type of receptor mediates the effects of norepinephrine that enhance calcium entry in cardiac cells?
What type of receptor mediates the effects of norepinephrine that enhance calcium entry in cardiac cells?
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Study Notes
Calcium Channel Blockers (CCBs)
- CCBs prevent calcium ions from entering cells, principally affecting heart and blood vessels.
- Widely used to treat hypertension, angina pectoris, and cardiac dysrhythmias.
- Controversy exists regarding CCB safety, particularly in hypertensive and diabetic patients. Safety concerns noted regarding increased mortality and MI risk with immediate-release nifedipine and some other immediate-release CCBs.
Calcium Channels: Physiologic Functions and Blockade
- Calcium channels are gated pores controlling calcium ion entry into cells, vital for vascular smooth muscle (VSM) and heart function.
- In VSM, calcium channel opening triggers contraction; blockade results in vasodilation.
- CCBs, at therapeutic doses, selectively target peripheral arterioles/arteries, minimally affecting veins. CCB effects on heart function are dose-dependent, with therapeutic doses impacting vessels primarily. Toxic doses can still cause cardiac suppression in all classes.
Calcium Channel Blockers: Classification and Sites of Action
- Two main categories: dihydropyridines and nondihydropyridines.
- Dihydropyridines primarily impact arterioles; nondihydropyridines affect both arterioles and the heart.
- Prototypes: Nifedipine (dihydropyridine), Verapamil and Diltiazem (nondihydropyridines). Several other dihydropyridines are available, including amlodipine, felodipine, etc. Table 39.1 details various agents, sites of action, and indications.
Nondihydropyridines: Verapamil and Diltiazem
-
Verapamil: Blocks calcium channels in blood vessels and heart. Used for angina pectoris, hypertension, and cardiac dysrhythmias.
- Direct effects: Peripheral vasodilation, enhanced coronary flow, slowed heart rate, reduced AV nodal conduction, and decreased contractility.
- Indirect (reflex) effects: Baroreceptor reflex to oppose direct heart effects, minimizing net cardiac impact.
- Overall effect: Vasodilation, decreased arterial pressure, and increased coronary flow.
- Oral administration; extensive first-pass metabolism; approximately 20% bioavailability.
- Common uses: Angina, hypertension, and cardiac dysrhythmias.
- Side effects: Frequent constipation, dizziness, flushing, headache, ankle edema. Careful use in patients with bradycardia, AV block, or heart failure; drug interactions (digoxin, beta-blockers, grapefruit juice) are significant.
-
Diltiazem: Similar actions and uses to verapamil, blocking calcium channels in heart and blood vessels for similar hemodynamic effects and therapeutic applications. Side effects generally similar to verapamil.
Dihydropyridines: Nifedipine
-
Nifedipine: Blocks calcium channels primarily in VSM, causing vasodilation and lowering blood pressure.
- Minimal impact on the heart at therapeutic doses.
- Useful for hypertension and angina but not dysrhythmias.
- Reflex tachycardia (especially with immediate-release formulations) is a possible side effect.
- Less likely than verapamil to worsen existing cardiac issues like AV block.
- Often combined with beta-blockers to manage reflex tachycardia; drug interactions (beta blockers) are noted.
- Immediate-release formulations linked to potential mortality and MI risks in certain patient populations (hypertension, unstable angina, MI), warranting particular caution; slow-release formulations are generally preferred.
Summary of Key Prescribing Considerations (Both Families)
- General: Monitor blood pressure (BP) and pulse, assess hepatic/renal function before initiating therapy.
- High-risk patients: Avoid in patients with hypotension, sick sinus syndrome, or second/third-degree AV block.
- Monitoring effects: Periodic BP monitoring, patient records of angina frequency/severity.
- Minimizing side effects: Start with low doses, adjust carefully, monitor weight daily, consider intermittent dosing schedule, note potential for chronic rashes in older patients.
Additional Considerations (from the new text)
- Patient-Specific Considerations (infants, children, pregnant women, breastfeeding women, older adults): Specific treatment considerations relevant to these age groups are now addressed as well (e.g., verapamil use in infants, nifedipine use in pregnancy, avoiding verapamil in breastfeeding, and potential for rashes in older patients). This portion of the notes is now more complete and reflects the patient-centric approach.
- Drug Interactions (Digoxin, Beta-blockers, Grapefruit Juice): Detailed drug interactions with other medications and food substances (i.e., digoxin, beta-blockers, and grapefruit juice) are now included for both Verapamil and Diltiazem.
- Dihydropyridines (Amlodipine, Nicardipine, etc.): Information related to other dihydropyridines like amlodipine and nicardipine is now integrated, providing a more comprehensive overview. Their uses, and similar prescribing considerations are discussed.
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Description
Test your knowledge on nifedipine, a calcium channel blocker, and its therapeutic uses, differences between formulations, and side effects. This quiz covers important aspects of nifedipine's clinical application in angina and other cardiovascular conditions.
