Equivalent Dosing for 360 mg Cardizem (Diltiazem)
360 mg of oral diltiazem daily is equivalent to approximately 7 mg/hour of intravenous diltiazem infusion. 1
IV to Oral Conversion
When converting between intravenous and oral formulations, the American College of Cardiology provides clear equivalencies:
- 3 mg/hour IV = 120 mg oral daily 1
- 5 mg/hour IV = 180 mg oral daily 1
- 7 mg/hour IV = 240 mg oral daily 1
Using this linear relationship, 360 mg oral daily corresponds to approximately 10.5 mg/hour IV, though the guideline-specified conversions only extend to 240 mg oral (7 mg/hour IV). 1
Clinical Context for 360 mg Dosing
The 360 mg daily dose represents the maximum recommended maintenance dose for most indications. 2
Dosing Range by Indication
- Hypertension: The American College of Cardiology recommends 120-360 mg daily, with hypertension often requiring higher doses (up to 360 mg daily) compared to angina. 2
- Angina: Typically requires 240 mg daily, which is lower than hypertension dosing. 2
- Extended-release formulations: Available as once-daily dosing at 180-420 mg, with 360 mg being within the standard therapeutic range. 2
Dose-Response Relationship
There is a clear linear dose-response relationship for blood pressure lowering through the 480-540 mg/day range, though 360 mg represents the typical maximum for routine use. 3 When the dose increases from 240 mg to 360 mg daily, there is an increase in area-under-the-curve of 1.8 times, demonstrating nonlinear pharmacokinetics. 4
Formulation Considerations
Cardizem CD (controlled-delivery) formulations allow once-daily dosing at 180-420 mg, with the 360 mg dose falling within this range. 2 The extended-release formulation maintains consistent blood levels over 24 hours. 2
Important Caveat
Extended-release capsules cannot be split, crushed, or divided—they must be swallowed whole to maintain their controlled-release properties. 5 This is a critical distinction from immediate-release tablets (30-120 mg), which can be crushed or chewed. 4
Monitoring at This Dose Level
At 360 mg daily, the American College of Cardiology recommends monitoring:
- Blood pressure and heart rate regularly 2
- Signs and symptoms of heart failure in at-risk patients 2
- ECG monitoring in patients with conduction system disease 2
- Liver function tests if clinically indicated 2
Common Adverse Effects at Higher Doses
Hypotension is the most common adverse effect, along with peripheral edema (dose-related, more common in women), bradycardia, and potential worsening of heart failure in patients with pre-existing ventricular dysfunction. 2