IV Diltiazem Dosing in Atrial Fibrillation

Today’s pearl is about an alternative diltiazem dosing method.

Weight-based diltiazem doses may be too high for some patients and fixed doses may offer similar efficacy with decreased risk of hypotension.

Traditionally, weight-based dosing is used for IV diltiazem in atrial fibrillation, 0.25 mg/kg followed by 0.35 mg, if the first dose is not effective.

However, one ED group compared a fixed 10 mg dose to weight-based dosing and found similar success between the two strategies. More than 60% achieved the primary outcome of successful treatment at 15 mins post-dose in both groups (Ross 2016). A separate group found no difference in total diltiazem dose needed between patients above and below 100 kg. About 30 mg was needed in each group (Zimmerman 2018). Interestingly, it took a mean of just over 2 hours for HR to drop below 100 bpm in both groups.

Take Home Points

  1. Either weight-based dosing or a standard 10 mg dose are both appropriate
  2. Expect about 30 mg may be needed in some patients
  3. Consider using the 10 mg strategy in patients with borderline initial blood pressures, older adults, and those anticipated to drop their blood pressure. The dose can be repeated q5-10 minutes.


Author: Bryan D. Hayes, PharmD

Attending Pharmacist, Emergency Medicine and Toxicology, Massachusetts General Hospital; Assistant Professor of EM, Harvard Medical School

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