Classes
DEA Class; Rx
Common Brand Names; Flagyl, Flagyl ER, Flagyl IV RTU
- Nitroimidazoles
metronidazole topical (Rx)
- Classes: Antibacterials, Topical
metronidazole vaginal (Rx)
- Classes: Antibiotics, Other;
- Vaginal Preparations, Other
Description
Oral/parenteral/topical/vaginal synthetic nitroimidazole; antibacterial and antiprotozoal
Used for anaerobic bacterial infections and protozoal infections such as trichomoniasis, amebiasis, and giardiasis
Associated with neurotoxicity
Indications
Indicated for the treatment of trichomoniasis.
Contraindications
Hypersensitivity to metronidazole or other nitroimidazoles (although cautious desensitization has been applied)
Pregnancy, 1st trimester in patients with trichomoniasis
Use of disulfiram within past 2 weeks; use of alcohol during therapy or within 3 days of discontinuing therapy
Consumption of alcohol or products containing propylene glycol within least three days of receiving metronidazole
Patients with Cockayne syndrome
Adverse Effects
- Appetite loss
- Candidiasis
- Diarrhea
- Dizziness
- Headache
- Nausea
- Vomiting
- Ataxia
- Dark urine
- Disulfiram-type reaction with ethanol
- Furry tongue
- Hypersensitivity
- Neutropenia
- Metallic taste
- Neuropathy
- Pancreatitis
- Seizures
- Thrombophlebitis
- Xerostomia
- Encephalopathy
- Aseptic meningitis
- Optic neuropathy
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Decreased libido
Warnings
Severe irreversible hepatotoxicity/acute liver failure with fatal outcomes reported after initiation of metronidazole, another nitroimidazole drug, structurally related to benznidazole in patients with Cockayne syndrome
Seizures and aseptic meningitis reported with increase in dose and chronic therapy
Cases of encephalopathy and peripheral neuropathy (including optic neuropathy) reported with metronidazole
Encephalopathy reported in association with cerebellar toxicity characterized by ataxia, dizziness, and dysarthria; CNS lesions seen on MRI described in reports of encephalopathy; CNS symptoms are generally reversible within days to weeks upon discontinuation of therapy; lesions seen on MRI have also been described as reversible
Peripheral neuropathy, mainly of sensory type reported and characterized by numbness or paresthesia of an extremity
Prescribing metronidazole tablets in absence of a proven or strongly suspected bacterial or parasitic infection or a prophylactic indication is unlikely to provide benefit to patient and increases risk of development of drug-resistant bacteria and parasites
Superinfection may occur with prolonged use
Severe hepatic impairment; administer lower doses with caution
Use with caution; potential accumulation in end stage renal disease; supplemental doses may be needed in patients receiving hemodialysis
Use with caution in history of heart failure, hepatic failure, H. pylori infection, renal impairment
Use with care in patients with evidence of or history of blood dyscrasia; agranulocytosis, leukopenia and neutropenia have been associated with metronidazole administration; monitor complete blood count; monitor complete blood count (CBC) for leukopenia before, during, and after prolonged repeated therapy
Avoid alcohol while taking medication and for at least three days after discontinuation
Antiandrogen: May cause gynecomastia
Known or previously unrecognized candidiasis may present more prominent symptoms during therapy and requires treatment with a candicidal agent
Pregnancy and Lactation
There are no adequate and well-controlled studies of in pregnant women; there are published data from case-control studies, cohort studies, and 2 meta-analyses that include more than 5000 pregnant women who used metronidazole during pregnancy
Metronidazole is present in human milk at concentrations similar to maternal serum levels, and infant serum levels can be close to or comparable to infant therapeutic levels
Maximum Dosage
2,250 mg/day IV/PO is usual maximum; however, up to 4 g/day IV/PO in FDA-approved labeling.
2,250 mg/day IV/PO is usual maximum; however, up to 4 g/day IV/PO in FDA-approved labeling.
50 mg/kg/day (Max: 2,250 mg/day) PO; safety and efficacy of IV use have not been established; however, doses up to 40 mg/kg/day (Max: 2,250 mg/day) IV have been used off-label.
50 mg/kg/day (Max: 2,250 mg/day) PO; safety and efficacy of IV use have not been established; however, doses up to 40 mg/kg/day (Max: 2,250 mg/day) IV have been used off-label.
50 mg/kg/day PO; safety and efficacy of IV have not been established; however, doses up to 40 mg/kg/day IV have been used off-label.
Postmenstrual age (PMA) older than 40 weeks: Safety and efficacy have not been established; however, doses up to 30 mg/kg/day IV have been used off-label.
PMA 35 to 40 weeks: Safety and efficacy have not been established; however, doses up to 22.5 mg/kg/day IV have been used off-label.
PMA 34 weeks and younger: Safety and efficacy have not been established; however, doses up to 15 mg/kg/day IV have been used off-label.
How supplied
Metronidazole
capsule
- 375mg
tablet
- 250mg
- 500mg
tablet, extended-release
- 750mg
infusion solution
- 500mg/100mL
topical gel
- 1% (MetroGel)
topical cream
- 0.75% (MetroCream)
- 1% (Noritate)
topical lotion
- 0.75% (MetroLotion)
vaginal gel
- 0.75% (MetroGel Vaginal, Vandazole)
- 1.3% (Nuvessa)