Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Metronidazole and tinidazole may slow down how quickly your body removes fluorouracil.
What might happen:
The amount of fluorouracil in your body may increase and cause additional or more severe side effects.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Let your doctor know if you notice any additional side effects or if your side effects are worse while you are taking these medicines together. Your doctor may check your blood counts more frequently while you take these medicines together. Your doctor may need to change the dosage of your fluorouracil while you are taking metronidazole or tinidazole.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Bardakji Z, Jolivet J, Langelier Y, Besner JG, Ayoub J. 5-Fluorouracil-metronidazole combination therapy in metastatic colorectal cancer. Clinical, pharmacokinetic and in vitro cytotoxicity studies. Cancer Chemother Pharmacol 1986;18(2):140-4.
2.Tindamax (tinidazole) US prescribing information. Presutti Laboratories, Inc. August, 2007.