We’ve had a couple prior alerts regarding the potential cardiovascular risks of macrolides. These have been taken with quite the grain of salt, particularly considering macrolides were, at one point, prescribed in a trial thought to be cardioprotective.
This meta-analysis is probably the most reasonable data to date on the subject. These authors (of which there are 17) gather 33 studies comprising 20,779,963 participants. These studies show, reasonably consistently, small increases in ventricular arrhythmias and sudden cardiac death. The relative risks reported are 2.52 for VT and 1.31 for SCD, and there was not much reliable variation between different macrolide antibiotics.
However, these relative risks translate into just a handful of additional cases per million prescriptions. The number needed to harm with cardiovascular death is about 25,000. On the flip side, across the included studies, the all-cause mortality was unchanged. So, yes, perhaps macrolides are not entirely benign – but neither is the underlying condition for which they are prescribed.
Overall, this study doesn’t add much to our insight into appropriate macrolide usage. There may be particular subgroups for whom they may be best avoided, but, the alternative agent must be equally effective against the existing pathology – and not have its own particular undesired interaction.
Of course, if macrolides are used in context where their benefit is minimal or zero – then there is only harm.
“The Role of Macrolide Antibiotics in Increasing Cardiovascular Risk”
The risk is also macrolide dependent, clarithromycin and erythromycin are more problematic. More concerning is the rampant use of azithromycin for possible CAP in settings where macrolide resistant pneumococci is common. There is a risk vs. benefit for everything in medicine and you need to ask yourself this question each time.