Podcast
Questions and Answers
What is the primary mechanism by which diltiazem achieves its therapeutic effects in conditions like hypertension and angina?
What is the primary mechanism by which diltiazem achieves its therapeutic effects in conditions like hypertension and angina?
- Inhibiting the renin-angiotensin-aldosterone system (RAAS) to reduce blood volume.
- Blocking calcium influx in cardiac and vascular smooth muscle, leading to vasodilation and reduced heart rate. (correct)
- Stimulating beta-adrenergic receptors to increase heart rate and blood pressure.
- Enhancing sodium influx in cardiac myocytes to increase contractility.
In which of the following clinical scenarios is the use of diltiazem absolutely contraindicated?
In which of the following clinical scenarios is the use of diltiazem absolutely contraindicated?
- Atrial fibrillation with a rapid ventricular response and systolic blood pressure of 100 mmHg.
- Hypertension with concomitant stable chronic obstructive pulmonary disease (COPD).
- Stable angina pectoris with normal left ventricular function.
- Second-degree AV block Mobitz Type I (Wenckebach) without a pacemaker. (correct)
A patient receiving diltiazem develops profound bradycardia. Which of the following interventions is the MOST appropriate initial step in managing this adverse effect?
A patient receiving diltiazem develops profound bradycardia. Which of the following interventions is the MOST appropriate initial step in managing this adverse effect?
- Initiating treatment with intravenous amiodarone to stabilize cardiac rhythm.
- Administering intravenous furosemide to reduce fluid overload.
- Administering intravenous calcium gluconate to counteract the calcium channel blockade. (correct)
- Preparing for transvenous pacing in case of further deterioration.
A patient is prescribed both diltiazem and a statin medication. What potential drug interaction should the healthcare provider be MOST concerned about?
A patient is prescribed both diltiazem and a statin medication. What potential drug interaction should the healthcare provider be MOST concerned about?
A patient with hepatic impairment is prescribed diltiazem. Which of the following considerations is MOST critical regarding the medication's use in this patient population?
A patient with hepatic impairment is prescribed diltiazem. Which of the following considerations is MOST critical regarding the medication's use in this patient population?
In the management of atrial fibrillation with rapid ventricular response, when is diltiazem considered a preferred agent for rate control?
In the management of atrial fibrillation with rapid ventricular response, when is diltiazem considered a preferred agent for rate control?
A patient is receiving a continuous IV infusion of diltiazem for rate control in atrial fibrillation. Which parameters require the MOST vigilant monitoring?
A patient is receiving a continuous IV infusion of diltiazem for rate control in atrial fibrillation. Which parameters require the MOST vigilant monitoring?
A patient on diltiazem complains of persistent lower extremity edema. What is the MOST likely mechanism contributing to this side effect?
A patient on diltiazem complains of persistent lower extremity edema. What is the MOST likely mechanism contributing to this side effect?
What is the MOST important consideration when transitioning a patient from intravenous diltiazem to oral diltiazem for long-term rate control?
What is the MOST important consideration when transitioning a patient from intravenous diltiazem to oral diltiazem for long-term rate control?
Which of the following statements regarding diltiazem's use in pregnancy is MOST accurate?
Which of the following statements regarding diltiazem's use in pregnancy is MOST accurate?
Flashcards
What is Diltiazem?
What is Diltiazem?
A non-dihydropyridine calcium channel blocker used to control heart rate, manage hypertension, and treat angina.
Diltiazem Contraindications
Diltiazem Contraindications
Severe hypotension, cardiogenic shock, 2nd or 3rd-degree AV block (without pacemaker), or acute decompensated heart failure.
Diltiazem Dosage
Diltiazem Dosage
IV: 0.25 mg/kg bolus, then 0.35 mg/kg if needed, infusion at 5-15 mg/hr. Oral: Varies per formulation (e.g., Cardizem CD once daily).
Diltiazem Onset and Half-Life
Diltiazem Onset and Half-Life
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Diltiazem Metabolism
Diltiazem Metabolism
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Diltiazem Side Effects
Diltiazem Side Effects
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Diltiazem Interactions
Diltiazem Interactions
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Diltiazem Monitoring
Diltiazem Monitoring
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Diltiazem Overdose Treatment
Diltiazem Overdose Treatment
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Diltiazem in ACLS
Diltiazem in ACLS
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Study Notes
- Diltiazem (Cardizem) is a non-dihydropyridine calcium channel blocker.
- It is used for rate control in atrial fibrillation/flutter.
- It is used for hypertension.
- It is used for angina.
- Diltiazem inhibits calcium influx in cardiac and vascular smooth muscle.
- It results in reduced heart rate.
- It results in reduced contractility.
- It results in vasodilation.
Contraindications
- Severe hypotension (SBP < 90 mmHg) is a contraindication.
- Cardiogenic shock is a contraindication.
- Second- or third-degree AV block (without a pacemaker) is a contraindication.
- Acute decompensated heart failure is a contraindication.
- It has negative inotropic effects.
Dosing
- IV boluses are given at 0.25 mg/kg over 2 minutes.
- Follow with 0.35 mg/kg if needed.
- Continuous infusion starts at 5-15 mg/hr, titrated to heart rate.
- Oral forms include extended-release (e.g., Cardizem CD, Tiazac) taken once daily.
- Immediate-release formulations are dosed multiple times per day.
Pharmacokinetics
- Onset of action is within 2-5 minutes IV.
- Onset of action is within 30-60 minutes orally.
- Peak effect is at 2-4 hours for oral extended-release.
- Half-life is about 3-5 hours (up to 9 hours in sustained-release forms).
- It is metabolized extensively by the liver (CYP3A4).
- It is excreted renally and in bile.
- Caution is needed in hepatic impairment.
- Renal dose adjustments are generally not required.
Side Effects
- Common side effects include bradycardia.
- Common side effects include hypotension.
- Common side effects include dizziness.
- Common side effects include headache.
- Common side effects include edema.
- Serious adverse effects can include heart block.
- Serious adverse effects can include worsening heart failure.
- Serious adverse effects can include severe hypotension.
Drug Interactions
- Significant interactions occur with beta-blockers (risk of profound bradycardia).
- CYP3A4 inhibitors or inducers affect diltiazem metabolism.
- Statins increase statin levels and risk of myopathy.
Monitoring
- Blood pressure requires monitoring.
- Heart rate requires monitoring.
- ECG requires monitoring, especially in ICU patients receiving IV infusions.
Toxicity
- Symptoms include profound bradycardia.
- Symptoms include hypotension.
- Symptoms include AV block.
- Treatment involves IV calcium.
- Treatment involves fluids.
- Treatment involves vasopressors.
- Treatment involves glucagon.
- Treatment involves high-dose insulin therapy in severe cases.
ACLS
- It is a preferred agent for rate control in stable narrow-complex tachycardias (e.g., atrial fibrillation with rapid ventricular response).
- It is contraindicated in wide-complex tachycardia.
Pregnancy
- Diltiazem is pregnancy category C.
- It should be used cautiously in pregnancy and lactation.
Cost
- IV formulations are more expensive than oral versions.
- It is widely available in hospital formularies.
Hospital protocols
- Hospitals often have protocols for using diltiazem IV infusions for atrial fibrillation with rapid ventricular response (RVR).
- Titration is required.
- Nursing monitoring for hypotension and bradycardia is required.
- Due to its negative inotropic effects, it is generally avoided in patients with heart failure with reduced ejection fraction (HFrEF).
- ICU physicians must know when and how to use diltiazem for acute rate control.
- ICU physicians must know how to transition from IV to oral formulations.
- ICU physicians must know how to manage side effects and interactions in critically ill patients.
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Description
Learn about diltiazem (Cardizem), a calcium channel blocker used for rate control in atrial fibrillation, hypertension, and angina. Understand its mechanism of action, contraindications such as hypotension and AV block, and proper dosing guidelines for IV and oral forms.
