From the Guidelines
The maximum recommended oral dose of diltiazem is 360 mg daily in divided or single dose with long-acting formulations. This dose is based on the most recent and highest quality study available, which is the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Key Points to Consider
- The dose of diltiazem may need to be adjusted based on patient response and tolerability.
- Elderly patients and those with hepatic or renal impairment may require lower doses.
- Diltiazem works by blocking calcium channels in vascular smooth muscle and cardiac tissue, causing vasodilation and decreased cardiac contractility, which reduces blood pressure and myocardial oxygen demand.
- Common side effects include headache, dizziness, edema, and constipation.
- Blood pressure and heart rate should be monitored regularly during dose adjustments to ensure efficacy and safety.
Potential Adverse Effects and Precautions
- Hypotension, worsening HF in patients with pre-existing ventricular dysfunction, bradycardia, abnormal liver function studies, acute hepatic injury (rare) are potential adverse effects of diltiazem.
- Precautions include AV block greater than first degree or SA node dysfunction (in absence of pacemaker), hypotension, decompensated systolic HF/severe LV dysfunction, WPW with AF/atrial flutter, and drugs with SA and/or AV nodal–blocking properties 1.
Comparison with Other Studies
- Other studies, such as the 2016 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1, and the 2015 pediatric pulmonary hypertension guidelines 1, also support the maximum recommended oral dose of diltiazem as 360 mg daily.
- However, the 2006 ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation 1 provide different dosing information for diltiazem, but this is not relevant to the current question.
From the Research
Maximum Recommended Dose of Diltiazem Oral
The maximum recommended dose of diltiazem oral varies depending on the specific formulation and the condition being treated.
- For the treatment of hypertension, the maximum dose can range from 360 mg/day to 540 mg/day, as seen in studies 2, 3.
- For the treatment of angina, the maximum dose is commonly 240 mg/day, but can be as high as 360 mg/day, as noted in 2, 4.
Diltiazem Formulations and Dosing
Different formulations of diltiazem have different dosing recommendations:
- The sustained-release formulation can be taken once daily, with a maximum dose of 300 mg, as shown in 5.
- The extended-release formulation can be taken once daily, with doses ranging from 120 mg to 540 mg, as demonstrated in 3.
Factors Influencing Dose
The optimal dose of diltiazem can depend on various factors, including:
- Patient age: elderly patients may require lower doses, as seen in 4, where the optimal daily dose for elderly patients with stable angina was found to be 180 mg/day.
- Condition being treated: hypertension or angina, with different dose ranges for each condition, as noted in 2, 3, 4.
- Formulation: different formulations have different dosing recommendations, as shown in 5, 3.