AMRIZOLE 200/MG/5/ML SUSP 120ML

Indications

Approved Uses

Treatment of susceptible anaerobic bacterial infections and protozoal infections including trichomoniasis, bacterial vaginosis, amoebiasis (intestinal and hepatic), and giardiasis.

Off-Label Uses

Common off-label uses include: part of combination regimens for Helicobacter pylori eradication (where used), perioperative prophylaxis for colorectal surgery (in combination), and certain dental/periodontal anaerobic infections; topical metronidazole is used for rosacea (topical indication may be labeled in some markets).

Dosage & Administration

Dosing by Condition

Use condition-specific guideline/label dosing; common adult oral regimens include: bacterial vaginosis 500 mg twice daily for 7 days; trichomoniasis 2 g single dose OR 500 mg twice daily for 7 days (often preferred in women); amoebiasis 500-750 mg three times daily for 5-10 days; giardiasis 250 mg three times daily for 5-7 days. Pediatric dosing is weight-based (commonly ~7.5 mg/kg/dose every 8 hours for invasive anaerobic/protozoal infections, per indication).

Initial Dose

Usual adult oral dosage is 7.5 mg/kg every six hours (approximately 500 mg for a 70-kg adult).

Maintenance Dose

Varies by indication; e.g., 500mg twice daily for 7 days for bacterial vaginosis.

Maximum Dose

4 g/day (adult maximum total daily dose, depending on indication).

Children's Dosage

7.5mg/kg (up to 400mg) three times daily; for neonates: 7.5mg/kg twice daily; suspension formulation suitable for pediatric use

Dose Adjustment Notes

Hepatic impairment: reduce dose in severe hepatic dysfunction (e.g., Child-Pugh C) and monitor for toxicity. Renal impairment: no routine adjustment, but metabolites may accumulate in severe renal failure; hemodialysis removes drug-consider post-dialysis dosing if on scheduled doses.

How to Take

Shake well before each dose. Measure with an oral syringe/medicine spoon. May be taken with food or milk to reduce GI upset; take with water as needed. Complete the full prescribed course.

How to Prepare

N/A (ready-to-use oral suspension); shake well before each use.

Side Effects

Common Side Effects

Nausea, vomiting, diarrhea/abdominal pain, metallic taste, headache, dizziness, and dark urine; less commonly dry mouth and constipation.

Side Effect Frequency

Common: nausea, metallic taste, headache, abdominal pain, diarrhea. Uncommon/rare but serious: peripheral neuropathy, seizures/encephalopathy, leukopenia, pancreatitis, severe hypersensitivity reactions, hepatotoxicity.

Safety & Warnings

Contraindications

Contraindications: hypersensitivity to metronidazole/other nitroimidazoles; concomitant disulfiram use or use within the last 14 days; patients with Cockayne syndrome; (for trichomoniasis) use in the first trimester of pregnancy. Alcohol/propylene glycol are not absolute contraindications but must be avoided during therapy and for at least 3 days after.

Warnings & Precautions

Key warnings/precautions: avoid alcohol and propylene glycol during therapy and for at least 3 days after; monitor for and discontinue if significant neurologic toxicity (seizures, encephalopathy, peripheral neuropathy) occurs; risk of superinfection (e.g., candidiasis) with prolonged use; use caution/monitor in hepatic impairment and in patients with blood dyscrasias; urine darkening may occur and is usually benign.

Age Restriction

No strict minimum age; metronidazole oral suspension may be used in neonates, infants, children, and adults when clinically indicated under prescriber supervision (pediatric dosing is indication-specific).

Drug Interactions

Drug Interactions

Clinically important interactions include: disulfiram (psychotic reactions-avoid/contraindicated within 14 days); alcohol and propylene glycol (disulfiram-like reaction-avoid during and ≥3 days after); warfarin/other coumarins (↑INR/bleeding-monitor/adjust); lithium (↑lithium-monitor/adjust); phenytoin/phenobarbital (enzyme induction may ↓metronidazole; metronidazole may also affect phenytoin-monitor levels/response); cimetidine (may ↑metronidazole-monitor); busulfan (↑busulfan exposure/toxicity-avoid/monitor closely); fluorouracil (↑5-FU toxicity-monitor).

Interaction Severity

MAJOR: Disulfiram (avoid; psychotic reactions), alcohol/propylene glycol (avoid during and for at least 48-72 hours after; disulfiram-like reaction), busulfan (avoid/monitor closely; increased exposure/toxicity). MODERATE: Warfarin (↑INR/bleeding-monitor/adjust), lithium (↑levels/toxicity-monitor), phenytoin/phenobarbital (enzyme induction may ↓metronidazole; metronidazole may ↑phenytoin-monitor), cimetidine (may ↑metronidazole levels).

Food Interaction

May be taken with food or milk to reduce gastrointestinal upset; food does not meaningfully reduce efficacy.

Special Populations

Children

7.5mg/kg (up to 400mg) three times daily; for neonates: 7.5mg/kg twice daily; suspension formulation suitable for pediatric use

Kidney Impairment

No routine dose adjustment in renal impairment; in end-stage renal disease/metronidazole metabolite accumulation may occur-monitor for adverse effects, and hemodialysis can remove drug/metabolites so consider post-dialysis dosing if clinically needed (especially with prolonged therapy).

Storage & Patient Advice

Storage Conditions

Store below 25°C (per SFDA) and keep the bottle tightly closed. If this product is supplied as a dry powder for reconstitution: after reconstitution store at 2-8°C and discard after 7 days (follow the package insert if different).

Preparation Instructions

N/A (ready-to-use oral suspension); shake well before each use.

Missed Dose

Take the missed dose as soon as remembered; if it is close to the next dose, skip the missed dose and resume the regular schedule-do not double doses.

Stopping the Medicine

Complete the full course of therapy as prescribed, even if symptoms improve, to prevent the development of resistance.

Overdose

Overdose may cause nausea, vomiting, and ataxia; neurotoxicity (e.g., seizures, peripheral neuropathy, confusion/encephalopathy) has been reported with very high doses/prolonged exposure; management is supportive/symptomatic (no specific antidote) and consider GI decontamination if recent ingestion per toxicology guidance.

Patient Counseling

Complete the full prescribed course. Shake well before each dose and measure with an oral syringe/cup. May take with food to reduce GI upset; metallic taste, nausea, and headache can occur. Avoid alcohol during treatment and for at least 48-72 hours after the last dose (disulfiram-like reaction); also avoid products containing propylene glycol during this period. Urine may darken (usually harmless). Seek medical advice urgently if you develop numbness/tingling (peripheral neuropathy), seizures, severe dizziness/confusion, or severe rash/allergic reaction. This is a prescription medicine and should not be shared. Store below 25°C (per SFDA).

Monitoring Requirements

Short courses: usually no routine labs. Prolonged/high-dose therapy: consider CBC (risk of leukopenia), LFTs in hepatic disease, and clinical monitoring for neurotoxicity (peripheral neuropathy, seizures) and severe GI effects.

Pharmacology

Mechanism of Action

Prodrug-like activation in anaerobic organisms/protozoa via reduction of the nitro group to reactive intermediates that damage DNA (strand breaks) and inhibit nucleic acid synthesis, leading to cell death.

Onset of Action

Peak plasma concentrations are reached in 1-2 hours after oral administration.

Duration of Effect

Approximate dosing interval effect is consistent with a half-life ~8 hours in adults; typical oral dosing is every 8-12 hours depending on indication.

Bioavailability

Oral bioavailability: >90% (approximately 90-100%).

Metabolism

Metabolism: hepatic, mainly via oxidation and glucuronidation; forms active metabolites (e.g., hydroxy-metronidazole).

Excretion

Excretion: primarily renal/urinary (~60-80% as parent drug and metabolites), with a smaller fecal component (~6-15%).

Protein Binding

<20% (low protein binding).

Product Information

Available Dosage Forms

Oral suspension (this product), oral tablets/capsules, IV infusion/solution, topical dermatologic preparations (gel/cream/lotion), and vaginal gel/cream (market-dependent).

Composition per Dose

Each 5ml: 125mg metronidazole

Generic Availability

Yes

OTC Alternatives

No OTC alternative

Spectrum

Active against anaerobes (e.g., Bacteroides fragilis group, Clostridium) and certain protozoa.

Antibiotic Class

Nitroimidazole

Reviewed by Al Mujtama Pharmacy Medical Review Team. Last reviewed 08-07-2026