Drug Interaction Report

Thiabendazole may increase the blood levels and effects of levobupivacaine. Before you receive levobupivacaine, let your doctor know if you have been using thiabendazole. You may need a dose adjustment or closer monitoring by your doctor to safely use both medications. Let your doctor know if you experience dizziness, lightheadedness, anxiety, restlessness, tremors, twitching, numbness and tingling of the mouth and lips, metallic taste, ringing in the ears or blurred vision, , as these may be early symptoms of excessive levobupivacaine levels. 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 caffeine together with thiabendazole can increase the effects of caffeine. Contact your doctor if you experience loss of appetite, sleep problems, stomach pain, a fast heart rate, or a slow heart rate. 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.

Consumer information for this interaction is not currently available.

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.