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
- Either weight-based dosing or a standard 10 mg dose are both appropriate
- Expect about 30 mg may be needed in some patients
- 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.