FDA label 6f1cc189-b232-4900-8195-8b00580b0a57

WARNING Metronidazole has been shown to be carcinogenic in mice and rats (see Precautions ). Its use, therefore, should be reserved for the conditions described in the Indications and Usage section below.

Warnings Central and Peripheral Nervous System Effects: Convulsive seizures, encephalopathy, aseptic meningitis, optic and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity, have been reported in patients treated with metronidazole. The appearance of abnormal neurologic signs demands the prompt evaluation of the benefit/risk ratio of the continuation of therapy.

Adverse Reactions The most serious adverse reactions reported in patients treated with metronidazole injection have been convulsive seizures, encephalopathy, aseptic meningitis, optic and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity. Since persistent peripheral neuropathy has been reported in some patients receiving prolonged oral administration of metronidazole, patients should be observed carefully if neurologic symptoms occur and a prompt evaluation made of the benefit/risk ratio of the continuation of therapy. The following reactions have also been reported during treatment with Metronidazole Injection, USP. Gastrointestinal: Nausea, vomiting, abdominal discomfort, diarrhea and an unpleasant metallic taste. Hematopoietic: Reversible neutropenia (leukopenia). Dermatologic: Erythematous rash and pruritus. Central Nervous System: Encephalopathy, aseptic meningitis, optic neuropathy, headache, dizziness, syncope, ataxia, confusion and dysarthria. Local Reactions: Thrombophlebitis after intravenous infusion. This reaction can be minimized or avoided by avoiding prolonged use of indwelling intravenous catheters. Other: Fever. Instances of darkened urine have also been reported, and this manifestation has been the subject of a special investigation. Although the pigment, which is probably responsible for this phenomenon, has not been positively identified, it is almost certainly a metabolite of metronidazole and seems to have no clinical significance. The following adverse reactions have been reported during treatment with oral metronidazole: Gastrointestinal: Nausea, sometimes accompanied by headache, anorexia and occasionally vomiting; diarrhea, epigastric distress, abdominal cramping and constipation. Mouth: A sharp, unpleasant metallic taste is not unusual. Furry tongue, glossitis and stomatitis have occurred; these may be associated with a sudden overgrowth of Candida , which may occur during effective therapy. Hematopoietic: Reversible neutropenia (leukopenia); rarely, reversible thrombocytopenia. Cardiovascular: Flattening of the T-wave may be seen in electrocardiographic tracings. Central Nervous System: Encephalopathy, aseptic meningitis, convulsive seizures, optic neuropathy, peripheral neuropathy, dizziness, vertigo, incoordination, ataxia, confusion, dysarthria, irritability, depression, weakness and insomnia. Hypersensitivity: Urticaria, erythematous rash, Stevens-Johnson Syndrome, flushing, nasal congestion, dryness of the mouth (or vagina or vulva) and fever. Renal: Dysuria, cystitis, polyuria, incontinence, a sense of pelvic pressure and darkened urine. Other: Proliferation of Candida in the vagina, dyspareunia, decrease of libido, proctitis and fleeting joint pains sometimes resembling "serum sickness." If patients receiving metronidazole drink alcoholic beverages, they may experience abdominal distress, nausea, vomiting, flushing or headache. A modification of the taste of alcoholic beverages has also been reported. Rare cases of pancreatitis, which abated on withdrawal of the drug, have been reported. Crohn's disease patients are known to have an increased incidence of gastrointestinal and certain extraintestinal cancers. There have been some reports in the medical literature of breast and colon cancer in Crohn's disease patients who have been treated with metronidazole at high doses for extended periods of time. A cause and effect relationship has not been established. Crohn's disease is not an approved indication for Metronidazole Injection, USP.