The PharmERToxGuy - By jkoehl27 - July 28, 2018
"Author’s conclusions
Magnesium appears to have a synergistic effect when combined with other AV nodal blockers and should be combined with usual rate-control agents to obtain efficient and more rapid action. Additionally, magnesium at a dose of 9 grams was not associated with greater efficacy on rate control compared to 4.5 grams.
Application to Clinical Practice
- Greater decreases in heart rate throughout the 24-hour study period were achieved with the addition of magnesium. This is important because it may not be immediately evident during an ED stay if magnesium is helping, especially when using digoxin which takes longer to work (sometimes several hours).
- The most common AV nodal blocking agent in the study was digoxin. This is not reflective of general practice in the U.S. It is encouraging that in patients who received diltiazem or beta blockers, there was not an increased risk of bradycardia or hypotension. We need a study with magnesium + the AV nodal blocking agents used in the U.S.
- There was no difference in efficacy between the low- and high-dose group but less side effects were experienced in the low-dose group.
- In light of the Previous magnesium data and this new study, we suggest considering the addition of magnesium 4 grams IV in patients with rapid AF in the ED setting as an adjunct to traditional AV nodal blocks. We traditionally have used 2 gm, but 4 gm seems to be what may work in the highest-quality study to date. 4 gm is easier to prepare than 4.5 gm (4 gm is often available as a premixed preparation)."