Impact of medications on mIBG uptake, with specific attention to the heart: Comprehensive review of the literature

A critical review of the literature on drug interactions with mIBG uptake was performed to allow formulation of contemporary guidance regarding withholding medications prior to clinical imaging studies. Published information was extracted on the experimental system used, the quantitative characteristics of the measurements, and whether any data directly examining cardiac tissues were included. Level of evidence for each medication category was assessed on a qualitative scale of very low, low, medium, or high. Strength of medication effect for inhibition of mIBG uptake was judged as none, weak, moderate, or strong. The only medications for which level of evidence was judged high were labetalol and reserpine. Level of evidence was judged medium for tricyclic antidepressants, calcium channel blockers, and antiarrhythmics (specifically amiodarone). Evidence was judged sufficient to recommend withholding labetalol and the tricyclic antidepressants prior to mIBG cardiac imaging. Mechanistic evidence was sufficient to suggest consideration of withdrawal of sympathomimetic amines and serotonin-norepinephrine reuptake inhibitors (SNRIs). As there is strong evidence for inhibition of mIBG uptake in only a small number of compounds, clinical decisions regarding withdrawal of concomitant medications should be individualized by considering the potential consequences of a false-positive (artificially low cardiac uptake) imaging result.