Metrogel Vaginal Vs. Nitrofurantoin: Drug Comparison

Metronidazole vaginal gel is an antibiotic used to treat bacterial vaginosis by inhibiting the growth of anaerobic bacteria, effectively clearing the infection. Its FDA-approved indication is for the treatment of bacterial vaginosis in females 12 and older. It is available as a gel (pre-filled gel applicator) that is applied directly into the vagina, typically once in the evenings. Common side effects include vaginal itching, discharge, and irritation, while systemic side effects like nausea or headache are rare.

Nitrofurantoin is the active ingredient in brand-name medications including Macrobid^®. The information below is about brand name Macrobid. According to the FDA, “Generic medicines use the same active ingredients as brand-name medicines and work the same way, so they have the same risks and benefits as the brand-name medicines.”

Nitrofurantoin is an antibiotic used to treat urinary tract infections (UTIs) by inhibiting bacterial enzymes and proteins needed for bacterial growth, effectively killing the bacteria. Its FDA-approved indication is the treatment of urinary tract infections caused by susceptible bacteria, such as E. coli. Nitrofurantoin comes in oral capsule form, typically taken twice daily. Common side effects include nausea, headache, flatulence, and diarrhea, while more serious side effects can include lung toxicity or liver damage, especially with long-term use. It should be used with caution in patients with kidney disease.

Nitroimidazole antimicrobial

Nitrofuran antibiotic

Metronidazole vaginal gel is indicated:

• For the treatment of bacterial vaginosis in females 12 years of age and older

Macrobid (nitrofurantoin) is indicated:

• Only for the treatment of acute uncomplicated urinary tract infections (acute cystitis) caused by susceptible strains of Escherichia coli or Staphylococcus saprophyticus

• Typically administered intravaginally once

• Comes as 65 mg of metronidazole in 5 grams of gel (1.3%) in a prefilled applicator

• Typically taken orally twice daily

• Comes in 100 mg capsules

The most common adverse reactions observed in adult clinical studies (incidence ≥1%) were:

• Vulvovaginal candidiasis

• Headache

• Vulvovaginal itchiness

• Nausea

• Diarrhea

• Painful menstruation

The most common adverse reactions observed in pediatric clinical studies (incidence ≥1%) was:

• Vulvovaginal discomfort

In clinical trials of Macrobid, the most frequent clinical adverse events that were reported as possibly or probably drug-related were:

• Nausea (8%)

• Headache (6%)

• Flatulence (1.5%)

• History of hypersensitivity to metronidazole, parabens, other ingredients of the formulation, or other nitroimidazole derivatives

• Concomitant use of disulfiram or within 2 weeks of disulfiram

• Concomitant use of alcohol

• Drug interactions: warfarin and other coumarin anticoagulants, lithium

• Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications

• Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38–42 weeks gestation), during labor and delivery, or when the onset of labor is imminent

• Macrobid is contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with nitrofurantoin

• Macrobid is also contraindicated in those patients with known hypersensitivity to nitrofurantoin

• Drug interactions: antacids, uricosuric drugs

• Central and peripheral nervous system effects

• Interference with laboratory tests

• Breastfeeding: A lactating patient may pump and discard breastmilk during treatment and for 48 hours after the last dose

• Pulmonary reactions

• Liver toxicity

• Neuropathy

• Hemolytic anemia

• Clostridium difficile-associated diarrhea

• Pregnancy: This drug should be used during pregnancy only if clearly needed

• Breastfeeding: Because of the potential for serious adverse reactions from nitrofurantoin in nursing infants under one month of age, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother

*This information is from the metronidazole vaginal gel label used by Encube Ethicals Private Limited. See the Full Prescribing Information for more complete information. This information may not be accurate for all medications that include the active ingredient metronidazole.

*This information is from the label for brand name Macrobid^®. See the Full Prescribing Information for more complete information. Nitrofurantoin, the active ingredient in Macrobid, may also be the active ingredient in other medications, and this information may not be accurate for all medications that include the active ingredient nitrofurantoin.