Metronidazole is a drug belonging to the nitroimidazole class of antibiotics. It serves its purpose as an antibiotic, anti-protozoal & anti-parasitic drug.
USES
- Bacterial vaginosis
- Endometriosis
- Pelvic inflammatory disease (PID)
- Colitis
- Aspiration pneumonia
- Meningitis
- Topical rosacea
- Topical fungal wounds
- Intra-abdominal infections
- Lung abscess
- Periodontits/Gum disease
- Amebiasis like amebic dysentery & amebic liver abscess
- Oral infections
- Symptomatic & Asymptomatic trichomoniasis
- Giardiasis
- Eradication of H.Pyroli.
DOSAGE FOR METRONIDAZOLE
Dosage forms available:
- Film coated immediate release tablet: 250 mg, 500 mg
- Extended release (XR) tablet: 750 mg
- Capsule: 375 mg, 500 mg
- Vaginal route cream: 10% strength
- Suppository: 500 mg
- Topical cream/gel: 7.5 mg/g
- IV injection: 500 mg/100 mL
- Various combination doses & preparation with adjunct drugs.
Dosage intake:
- For vaginal infections, 250 mg/day for 7 days
- For various amoebic infections: 500 mg – 750 mg XR or capsule depending on the infection for 5-10 days.
- In Trichomoniasis: Metronidazole capsules are given (375 mg/ 2 times a day) for 7 days, or metronidazole tablets (250 mg/ 3 times a day) for 7 days.
- For various other infections doses are adjusted according to age, sex, weight, immune health, duration of infection, etc.
Missed dose: Other doses depend on factors like the type & location of infection, bacteria, age, sex, presence of underlying diseases, immunity & doctor’s guidance.
Overdose:
a) Doses above 4-5 mg per day can present with overdose.
b) Management with administration of gastric lavage & induction of vomiting to remove metronidazole from the stomach.
SIDE EFFECTS
- Diarrhea,
- Painful or difficulty urinating,
- Trouble sleeping,
- Depression,
- Irritability,
- Headache,
- Dizziness
- Weakness,
- Lightheadedness,
- Blisters or ulcers in your mouth,
- Red or swollen gums, and
- Trouble swallowing
- Numbness
ADVERSE EFFECTS
- Seizures/Convulsions
- Encephalopathy
- Optic nerve damage
- Paresthesia
- Damage to the nerves of the periphery
- Vertigo
- Confusion & ataxia
- Muscle weakness
- Severe abdominal pain accompanied with vomiting or diarrhea
- Metallic taste
- Furry tongue
- Pruritis
- Reduced WBC count
- Stevens-Johnson Syndrome
- Severe hypersensitivity reaction & signs
- Inflammation of the mouth
- Flattening of the T-wave in heart readings.
PRECAUTION & CONTRAINDICATION FOR METRONIDAZOLE
Metronidazole is contraindicated in patients & precaution is advised with following conditions:
- Cockayne Syndrome
- Patients with hepatic impairment metabolize metronidazole slowly
- ESRD
- Candidiasis
- Blood dyscrasia
- Patients with prior history of hypersensitivity
- In pregnant patients with trichomoniasis, metronidazole is contraindicated in the first trimester.
- Crohn’s Disease
- Anemia
- Drug allergy
- Metronidazole is contraindicated in patients that have alcohol addiction.
INTERACTIONS OF METRONIDAZOLE
- The drug should not be given in presence of disulfiram.
- Beverages or medicines containing Propylene Glycol, can lead to abdominal cramping, flushing, rashes, etc.
- Metronidazole increases the anti-coagulant activity of warfarin.
- Metronidazole when given in presence of lithium can lead to lithium toxicity.
- Increase plasma concentration of busulfan & subsequent toxicity.
- Drugs that inhibit CYP450 enzyme activity such as cimetidine can decrease plasma clearance time of metronidazole.
- Drugs like phenytoin that induce CYP540 enzyme activity can in turn increase its excretion.
- Can interfere with certain type of serum lab tests, blood tests & determinations of markers & enzymes.
- Metronidazole in presence with alcohol can lead to a severe unpleasant reaction called disulfiram reactions that leads to vomiting, abdominal cramping, headache, dizziness, weakness, heart problems, etc.
IN PREGNANCY, BREAST FEEDING & CHILDREN
- Pregnancy: No sufficient data is available for the effect that metronidazole may produce on pregnant women.
- Breast Feeding: The drug is present in breast milk, and due to its tumor causing factors is not recommended in breast feeding mothers.
- Children: Safety and effectiveness in pediatric patients have not been established, except for the treatment of amebiasis.