Is diltiazem (Cardizem) IVP (intravenous push) 10mg suitable for treating reflex vagal response (RVR) in a patient with hypotension, specifically a systolic blood pressure (SBP) of 110mmHg?

From the Guidelines

Administering diltiazem IVP 10mg for rapid ventricular response (RVR) with a systolic blood pressure (SBP) of 110 mmHg is acceptable, but caution is advised due to the potential risk of hypotension. The standard dose of diltiazem is 15-20 mg (0.25 mg/kg) IV over 2 minutes, but a reduced dose of 10 mg may be considered in patients with borderline blood pressure to minimize the risk of hypotension 1. When giving diltiazem in this situation, close monitoring of blood pressure and heart rate is essential, with equipment for blood pressure support readily available. Diltiazem works by blocking calcium channels in the heart, slowing conduction through the AV node and reducing heart rate in atrial fibrillation or flutter with RVR.

Some key points to consider when administering diltiazem in this context include:

• The patient should be on continuous cardiac monitoring with frequent blood pressure checks for at least 30 minutes after administration 1.
• If blood pressure drops significantly after the initial dose, subsequent doses should be withheld and supportive measures initiated.
• Diltiazem should only be given to patients with narrow-complex tachycardias (regular or irregular) and avoided in patients with heart failure and pre-excited AF or flutter or rhythms consistent with VT 1.
• The maintenance infusion dose of diltiazem is 5 mg/hour to 15 mg/hour, titrated to heart rate 1.

Overall, while diltiazem can be used to treat RVR in patients with a SBP of 110 mmHg, careful consideration of the potential risks and benefits, as well as close monitoring of the patient, is necessary to ensure safe and effective treatment.

From the FDA Drug Label

The use of diltiazem hydrochloride injection or diltiazem hydrochloride for injection should be undertaken with caution when the patient is compromised hemodynamically or is taking other drugs that decrease any or all of the following: peripheral resistance, myocardial filling, myocardial contractility, or electrical impulse propagation in the myocardium For either indication and particularly when employing continuous intravenous infusion, the setting should include continuous monitoring of the ECG and frequent measurement of blood pressure. A defibrillator and emergency equipment should be readily available In domestic controlled trials in patients with atrial fibrillation or atrial flutter, bolus administration of diltiazem hydrochloride injection was effective in reducing heart rate by at least 20% in 95% of patients. If hypotension occurs, it is generally short-lived, but may last from 1 to 3 hours In the controlled clinical trials, 3. 2% of patients required some form of intervention (typically, use of intravenous fluids or the Trendelenburg position) for blood pressure support following diltiazem hydrochloride injection

Diltiazem IVP 10mg for RVR may be given for a patient with a systolic blood pressure (SBP) of 110 mmHg, but it should be done with caution. The patient's hemodynamic status should be closely monitored, and the setting should include continuous monitoring of the ECG and frequent measurement of blood pressure. A defibrillator and emergency equipment should be readily available. It is also important to note that hypotension is a possible adverse effect of diltiazem, and the patient may require intervention for blood pressure support 2.

• Key considerations:
  • Closely monitor the patient's hemodynamic status
  • Continuous monitoring of the ECG and frequent measurement of blood pressure
  • Defibrillator and emergency equipment should be readily available
  • Hypotension is a possible adverse effect
  • Intervention for blood pressure support may be required 2

From the Research

Diltiazem Administration for RVR

• The administration of diltiazem for rapid ventricular rate (RVR) has been studied in various contexts, including atrial fibrillation and sinus tachycardia 3, 4.
• A study published in 2021 found that diltiazem bolus dosing ≥ 0.13 mg/kg was associated with significantly improved times to achieve heart rate control compared to < 0.13 mg/kg, without significant differences in lowest systolic blood pressure (SBP) and diastolic blood pressure (DBP) 3.
• Another study from 2001 reported that intravenous diltiazem was effective in achieving short-term control of heart rate in 56% of patients with sinus tachycardia, with a mean infusion rate of 13.3 mg/hr 4.

Safety and Efficacy

• The safety and efficacy of diltiazem in patients with various conditions, including essential hypertension and coronary artery disease, have been evaluated in several studies 5, 6.
• A 1983 study found that diltiazem was effective in lowering diastolic blood pressure and reducing peripheral resistance, with minimal side effects 5.
• A 1986 review of the hemodynamic effects of calcium antagonists, including diltiazem, noted that diltiazem produces similar effects to verapamil but has less potency in inducing arterial dilatation and more of a tendency to slow the heart rate 6.

Specific Considerations for 110 SBP

• While the provided studies do not specifically address the administration of diltiazem IVP 10mg for RVR in patients with a systolic blood pressure (SBP) of 110 mmHg, the available evidence suggests that diltiazem can be effective in controlling heart rate without causing significant hypotension 3, 4.
• However, it is essential to consider the individual patient's condition, medical history, and potential interactions with other medications when administering diltiazem 5, 6, 7.