Metronidazole Side Effects
Get immediate medical help if you experience signs of an allergic reaction to Metronidazole:
- Skin rash (which may be itchy), swelling of your face, lips, tongue, throat; difficulty breathing.
- Symptoms of rare brain disease (encephalopathy), which can include fever, stiff neck, headache, seeing or hearing things that are not there, trouble using your arms and legs, confusion, problems speaking.
- Signs of conditions such as ‘Stevens-Johnson Syndrome’ or ‘toxic epidermal necrolysis’. You may experience skin rashes with blistering, peeling or bleeding of the skin around the lips, eyes, mouth, nose and genitals, flu-like symptoms, high temperature.
Reported side effects of Metronidazole include:
- Nausea (feeling sick) or vomiting (being sick)
- Metallic taste in your mouth
- Changes in taste
- Furry tongue
- Loss of appetite
- Dry mouth
- Hypersensitivity (including hives, rash, flushing, nasal congestion, fever)
- Painful urination, frequent urination, darkened urine, pelvic pressure, inflammation of the bladder (Cystitis)
- Abdominal Cramps
- Dizziness, vertigo, confusion
- Depression, weakness, irritability, insomnia (inability to sleep)
- Ataxia (disorder affecting coordination, balance, speech)
- Epigastric distress (discomfort or pain right below your ribs)
- Painful sex, reduction of sex drive
- Joint pains
Rare but serious side effects include:
- Convulsive Seizures
- Numbness/burning/pain/tingling in your hands and/or feet (peripheral neuropathy)
If you experience any serious side effects, talk to your physician.
You should avoid consuming alcohol while you are taking Metronidazole and for at least 48 hours after the last dose in order to avoid abdominal distress, nausea, vomiting, flushing, or headaches.
If you have Crohn’s disease, talk to your physician about the potential impact of Metronidazole on your health, as patients with this condition have an increased risk of gastrointestinal and other cancers due to ongoing inflammation.
Metronidazole is contraindicated in the following patients:
- Patients with a prior history of intolerance and hypersensitivity to Metronidazole or other nitroimidazole derivatives (other forms under which Metronidazole is supplied such as gel, cream, a liquid you drink, or suppository).
- Patients with trichomoniasis (a sexually transmitted infection) in their first term of pregnancy.
Metronidazole may interfere with the following medicines:
- Disulfiram (drug to treat chronic alcoholism)
- Warfarin and other anticoagulants (blood thinners)
- Lithobid (lithium)
- Busulfan (cancer drug)
- Drugs that inhibit CYP450 Enzymes such as Phenytoin and Phenobarbital
- Astemizole (antihistamine used to treat allergies)
- Cimetidine (used to reduce stomach acid production
Always inform your doctor of the drugs, vitamins and herbal medicines you are taking before using Metronidazole.