Metrolex Drug Interactions

Concomitant uses of warfarin and Metronidazole may increase the serum concentration of warfarin. If concomitant therapy cannot be avoided, prothrombin times should be monitored and dosage of warfarin adjusted accordingly. There is no interaction between Metronidazole and heparin.
If Metronidazole is used in patients receiving lithium; Metronidazole may increase the serum lithium concentrations, resulting in signs of lithium toxicity. Lithium should be discontinued before Metronidazole is used in treatment. If concomitant therapy cannot be avoided, plasma concentration of lithium, creatinine and electrolytes should be monitored.
Concomitant use of Metronidazole and phenobarbital appears to decrease the serum half-life of Metronidazole/Metronidazole is metabolized with a much greater rate than normal. Serum concentrations of Metronidazole have been decreased.
Administration of disulfiram and Metronidazole has been associated with acute psychoses and confusion in some patients; therefore, the drugs should not be used concomitantly and 2 weeks should elapse following discontinuance of disulfiram prior to initiating Metronidazole therapy.
Disulfiram-like reactions including flushing, nausea, vomiting, palpitation and tachycardia have occurred in some patients who ingested alcohol while receiving Metronidazole. Alcohol should not be consumed during or for at least 1 day (or 3 days) following completion of Metronidazole therapy.
Concomitant use of Metronidazole and cimetidine appears to increase the plasma half-life and decrease total plasma clearance of Metronidazole. Serum concentrations of Metronidazole have been increased.
Concomitant use of Metronidazole and hydantoins may increase the serum concentration of phenytoin.
Injection: Metronidazole may interfere with aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), triglycerides and hexokinase glucose testing.