Drug Interactions between Biaxin XL and fosphenytoin

Talk to your doctor before using clarithromycin together with fosphenytoin. Combining these medications can alter the blood levels and effects of both medications. Specifically, clarithromycin levels may decrease, which may make the medication less effective in treating your infection. At the same time, fosphenytoin levels may increase, and you may experience more frequent and/or severe side effects. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if you experience nausea, vomiting, twitching eye movements, blurred vision, slurred speech, loss of balance or coordination, tremors, sluggishness, confusion, or hallucinations, as these may be symptoms of excessive effects of fosphenytoin. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.