Erythromycin markedly increases the bioavailability of
felodipine. Isolated reports describe increased
felodipine,
nifedipine or
verapamil effects and
toxicity in patients when given
erythromycin,
clarithromycin or
telithromycin. Note that the calcium- channel blockers are all metabolised by CYP3A4, so all have the potential to interact.
Monitor concurrent use. If adverse effects become troublesome (such as hypotension, dizziness, flushing and palpitations) adjust the calcium-channel blocker dose.