Drug Interactions between Bactrim and fosphenytoin

Trimethoprim may increase the blood levels and effects of fosphenytoin. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring 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.

Using fosphenytoin together with sulfamethoxazole may increase the effects of fosphenytoin. Contact your doctor if you experience twitching eye movements, slurred speech, loss of balance, tremor, muscle stiffness or weakness, nausea, vomiting, feeling light-headed, fainting, and slow or shallow breathing. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. 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.