Grapefruit juice appears to completely inhibit the
metabolism of
amiodarone to its major active
metabolite, increases the AUC of
amiodarone by 50% and increases the peak
serum level by 84%, which may lead to
toxicity. However, the effect of
amiodarone on the PR and QTc intervals is apparently decreased, possibly due to reduced levels of the active
metabolite.
Further study is needed. In the meantime, it may be prudent to suggest to patients that they avoid
grapefruit juice.