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Metronidazole 500 mg Tablet
Metronidazole 500 mg Tablet
Therapeutic Class: Anti-Infectives
Dosage Forms: Tablets
Brand Name: Metronidazole 500 mg Tablet™
PPB-KENYA
FDA-JORDAN
MOH-GHANA
WHO- GMP
MOH-MYANMAR
NAFDAC NIGERIA
How it works?
Uses of Metronidazole 500 mg Tablet
What are the Uses of Metronidazole 500 mg tablet?
- Anaerobic infections (caused by bacteria that thrive without oxygen), such as:
- Dental infections.
- Skin and soft tissue infections.
- Bone and joint infections.
- Abdominal infections (e.g., peritonitis)
Parasitic Infections
- Amebiasis—an intestinal infection caused by Entamoeba histolytica.
- Giardiasis—a diarrheal illness caused by Giardia lamblia.
Sexually Transmitted Infections (STIs)
- Trichomoniasis—caused by Trichomonas vaginalis, often treated in both partners.
Gynecological Conditions
- Bacterial vaginosis—imbalance of vaginal bacteria.
- Pelvic inflammatory disease (PID)—often used in combination with other antibiotics.
Gastrointestinal Conditions
- Helicobacter pylori infections—part of combination therapy for stomach ulcers.
- Clostridium difficile colitis—sometimes used when other treatments aren’t suitable.
Surgical Prophylaxis
- Given before surgery to prevent infection, especially in colorectal procedures.
Precautions of Metronidazole 500 mg Tablet
Precautions When Using Metronidazole 500 mg Tablet
Alcohol
- Do not drink alcohol during treatment and for 48 hours after stopping metronidazole. It can cause serious reactions like flushing and low blood pressure.
Health Conditions
- Porphyria: Use with caution.
- Blood disorders or brain conditions (not caused by infection): Avoid using metronidazole.
- Epilepsy or history of seizures: High doses may trigger seizures—use carefully.
- Syphilis: High doses may hide signs of syphilis—testing is important.
Pregnancy & Breastfeeding
- Pregnancy:
- Not safe in the first trimester.
- Use with caution in the second and third trimesters for vaginal infections.
- For other uses, only take if absolutely necessary and no safer option is available.
- Breastfeeding:
- Stop breastfeeding during treatment and for 12–24 hours after stopping the medicine.
Monitoring
- If treatment lasts more than 10 days, regular check-ups and lab tests are recommended.
- Long-term use may cause nerve damage—weigh the benefits and risks carefully.
Infections
- Even after treating Trichomonas vaginalis, other infections like gonorrhea may still be present—follow-up testing may be needed.
Kidney Function
- Kidney failure: No dose change needed, but the body may hold onto drug by-products. The effect of this is unclear.
- Hemodialysis: The drug is removed during dialysis—take a dose right after dialysis.
- Peritoneal dialysis (IPD or CAPD): No dose adjustment needed.
Liver Function
- Liver disease or encephalopathy: Use with caution. Reduce the dose to one-third and take once daily.
- Cockayne syndrome:
- Serious liver damage has occurred, sometimes fatal.
- Only use if absolutely necessary and no other treatment is available.
- Liver tests must be done before, during, and after treatment.
- Stop treatment if liver tests worsen.
- Report any signs of liver problems (like yellowing of skin or eyes) immediately.
Skin Reactions
- Rare but serious skin conditions like SJS, TEN, or AGEP have been reported.
- Stop the medicine immediately if you notice a rash, blisters, or peeling skin.
Other Notes
- Metronidazole may darken urine—this is harmless.
- Long-term use should be avoided unless absolutely necessary due to unclear risks related to genetic changes.
Dosages administration of Metronidazole 500 mg Tablet
Dosage & Administration Guide of Metronidazole 500 mg Tablet
General Administration Instructions
- Route: Oral use only
- Timing: Take during or after meals
- Method: Swallow whole with water; do not chew
Special Populations
Elderly
- Use with caution, especially at high doses
- Limited data on dosage modification
Hepatic Impairment
- In hepatic encephalopathy: → Administer ⅓ of the daily dose once daily.
Anaerobic Infections
| Age Group | Dosage | Frequency | Duration |
| Children >8 weeks to 12 years | 20–30 mg/kg/day | Single dose or 7.5 mg/kg every 8 hrs | Usually 7 days |
| Severe cases | Up to 40 mg/kg/day | — | — |
| Children <8 weeks | 15 mg/kg/day | Single dose or 7.5 mg/kg every 12 hrs | — |
| Preterm newborns (<40 weeks gestation) | Monitor serum levels | — | — |
Children under 10 years: Use a more suitable dosage form.
Prophylaxis (Anaerobic Infection – Surgical Context)
Adults
- 1 g stat dose 24 hrs pre-op
- Then 400 mg every 8 hrs for 24 hrs pre-op
- Continue post-op via IV or rectal route until oral intake is possible
Children <12 years
- 20–30 mg/kg as a single dose 1–2 hrs before surgery
Newborns (<40 weeks gestation)
- 10 mg/kg as a single dose before surgery
Children under 10 years: Use a more suitable dosage form.
Treatment of Established Infections.
| Age Group | Dosage | Frequency |
| Adults & Children >10 years | 800 mg initially | Then 400 mg every 8 hrs |
| Children <10 years | — | Use a more suitable dosage form |
Urogenital Trichomoniasis
| Group | Dosage Options |
| Adults & Adolescents | 2000 mg single dose OR 200 mg 3× daily for 7 days OR 400 mg 2× daily for 5–7 days |
| Children <10 years | 40 mg/kg single dose OR 15–30 mg/kg/day in 2–3 doses for 7 days (Max 2000 mg/day) |
Treat sexual partners simultaneously to prevent reinfection.
Bacterial Vaginosis
| Group | Dosage Options |
| Adults | 400 mg 2× daily for 7 days OR 2000 mg single dose |
| Adolescents | 400 mg 2× daily for 5–7 days OR 2000 mg single dose |
Amoebiasis
| Age Group | Dosage | Frequency | Duration |
|---|---|---|---|
| Adults over 10 years | 400–800 mg | 3× daily | 5–10 days |
| Children 7–10 years | 200–400 mg | 3× daily | 5–10 days |
| Children 3–7 years | 100–200 mg | 4× daily | 5–10 days |
| Children 1–3 years | 100–200 mg | 3× daily | 5–10 days |
| Alternative (All ages) | 35–50 mg/kg/day | 3 divided doses | Max 2400 mg/day |
Children under 7 years: Use a more suitable dosage form.
Giardiasis
| Age Group | Dosage Options | |
| Adults >10 years | 2000 mg once daily for 3 days OR 400 mg 3× daily for 5 days OR 500 mg 2× daily for 7–10 days | |
| Children 7–10 years | 1000 mg once daily for 3 days | |
| Children 3–7 years | 600–800 mg once daily for 3 days | |
| Children 1–3 years | 500 mg once daily for 3 days | |
| Alternative | 15–40 mg/kg/day | Divided in 2–3 doses |
Children under 7 years: Use a more suitable dosage form.
Dental & Skin Infections
| Condition | Age Group | Dosage | Duration |
|---|---|---|---|
| Acute Ulcerative Gingivitis | Adults & Children >10 years | 200 mg 3× daily | 3 days |
| Acute Dental Infections | Adults & Children >10 years | 200 mg 3× daily | 3–7 days |
| Leg Ulcers/Pressure Sores | Adults & Children >10 years | 400 mg 3× daily | 7 days |
Children under 10 years: Use a more suitable dosage form.
Helicobacter pylori (Combination Therapy)
- 20 mg/kg/day.
- Max dose: 500 mg twice daily.
- Duration: 7–14 days.
- Follow official guidelines before initiating therapy.
Side effects of Metronidazole 500 mg Tablet
Side Effects of Metronidazole 500 mg Tablet
- Alcohol: Avoid alcohol during treatment and for 48 hours after stopping metronidazole. It may cause flushing, low blood pressure, and other serious reactions.
- Porphyria: Use with caution.
- Blood & CNS Conditions: Do not use in patients with blood disorders or active non-infectious brain diseases.
- Syphilis: High doses may mask symptoms—ensure proper testing.
- Seizure Risk: Use cautiously in patients with epilepsy or seizure history.
- Pregnancy: Use with caution in the 2nd and 3rd trimesters for vaginal infections.
- Long-Term Use: If treatment exceeds 10 days, regular clinical and lab monitoring is advised.
- Peripheral Neuropathy: Weigh benefits vs. risks in chronic use.
- Trichomoniasis: Gonorrhea may persist even after Trichomonas is treated—follow-up testing may be needed.
- Renal Impairment:
- No dose adjustment is needed, but metabolites may accumulate.
- Hemodialysis: Re-administer metronidazole immediately after dialysis.
- Peritoneal Dialysis (IPD/CAPD): No dose adjustment required.
- Liver Impairment:
- In hepatic encephalopathy, reduce the dose to one-third, given once daily.
- In Cockayne syndrome, metronidazole should only be used if no alternatives exist. Liver function tests are mandatory before, during, and after treatment. Discontinue if liver values worsen.
- Skin Reactions: Discontinue immediately if signs of SJS, TEN, or AGEP appear.
- Urine Discoloration: May darken urine—this is harmless.
- Mutagenicity Risk: Long-term use should be avoided unless absolutely necessary.
Storage instruction of Metronidazole 500 mg Tablet
Store below 30°C.
Keep out of reach of children.
Packing details of Metronidazole 500 mg Tablet
6×3 Alu/PVC Blister
Metronidazole 500 mg tablets are available in an Alu/PVC blister of 6 tablets. Such 3 blisters in a unit carton with a package insert.
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