The following reactions have been reported during treatment with metronidazole:
Central Nervous System: The most serious adverse reactions reported in patients treated with metronidazole 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 administration of metronidazole, patients should be specifically warned about these reactions and should be told to stop the drug and report immediately to their physicians if any neurologic symptoms occur. In addition, patients have reported headache, syncope, dizziness, vertigo, incoordination, ataxia, confusion, dysarthria, irritability, depression, weakness, and insomnia (see
Gastrointestinal: The most common adverse reactions reported have been referable to the gastrointestinal tract, particularly 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 therapy.
Dermatologic: Erythematous rash and pruritus.
Hematopoietic: Reversible neutropenia (leukopenia); rarely, reversible thrombocytopenia.
Cardiovascular: Flattening of the T-wave may be seen in electrocardiographic tracings.
Hypersensitivity: Urticaria, erythematous rash, Stevens-Johnson Syndrome, toxic epidermal necrolysis, flushing, nasal congestion, dryness of the mouth (or vagina or vulva), and fever.
Renal: Dysuria, cystitis, polyuria, incontinence, and a sense of pelvic pressure. Instances of darkened urine have been reported by approximately one patient in 100,000. 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.
Other: Proliferation of Candida in the vagina, dyspareunia, decrease of libido, proctitis, and fleeting joint pains sometimes resembling "serum sickness." Rare cases of pancreatitis, which generally abated on withdrawal of the drug, have been reported.
Patients with Crohn's disease 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 FLAGYL 375 capsules.
REPORTS OF SUSPECTED FLAGYL SIDE EFFECTS / ADVERSE REACTIONS
Below is a sample of reports where side effects / adverse reactions may be related to Flagyl. The information is not vetted and should not be considered as verified clinical evidence.
Possible Flagyl side effects / adverse reactions in 68 year old female
Reported by a consumer/non-health professional from United States on 2011-10-03
Patient: 68 year old female
Possible Flagyl side effects / adverse reactions in 49 year old female
Reported by a consumer/non-health professional from United States on 2011-10-04
Patient: 49 year old female weighing 62.1 kg (136.7 pounds)
Reactions: Pyrexia, Muscle Spasms
Possible Flagyl side effects / adverse reactions in 36 year old female
Reported by a pharmacist from United States on 2011-10-06
Patient: 36 year old female weighing 99.8 kg (219.6 pounds)
Adverse event resulted in: hospitalization
Other drugs received by patient: Trazodone Hydrochloride; Cymbalta; Valium; Xanax; Phentermine; Albuterol; Cardura; Zegerid; Zofran; Dilaudid; Mirapex; Pravastatin