Schedule H

Oral

• Tablets: Amoxicillin 500 mg + Tinidazole 600 mg

• Tablets: Amoxicillin 250 mg + Tinidazole 300 mg

• Suspension: NOT AVAILABLE in India

INDICATIONS + DOSING — FOR CLINICIAN USE ONLY

Primary Indications (Approved / Standard in India):

1. Amoebic Dysentery / Giardiasis with Suspected Mixed Bacterial-Protozoal Infection — Adults

Parameter Recommendation

Starting dose 1 tablet (500 mg + 600 mg) twice daily

Titration Not applicable

Usual maintenance dose 1 tablet twice daily

Maximum dose 2 tablets twice daily (rarely required)

Duration 5–7 days

Clinical note Preferred when invasive Entamoeba histolytica or concomitant bacterial superinfection suspected; take with food to reduce GI upset

1. Dental Infections with Anaerobic Component (Acute Periapical Abscess, Pericoronitis) — Adults

Parameter Recommendation

Starting dose 1 tablet (500 mg + 600 mg) twice daily

Titration Not applicable

Usual maintenance dose 1 tablet twice daily

Maximum dose 1 tablet twice daily

Duration 5–7 days (short-course preferred)

Clinical note Covers gram-positive aerobes and oral anaerobes; commonly used in Indian dental practice for odontogenic infections

1. Pre-operative / Post-operative Prophylaxis (Colorectal, Gynaecological Surgery) — Adults

Parameter Recommendation

Starting dose 1 tablet (500 mg + 600 mg) once or twice daily

Titration Not applicable

Usual maintenance dose 1 tablet once–twice daily

Maximum dose 1 tablet twice daily

Duration 1 day before + day of surgery; rarely continued beyond 24–48 hours post-operatively

Clinical note Empirical use in selected GI/gynaecological surgeries; institutional protocols vary; not universally endorsed in all settings

Secondary Indications — Adults (Off-label)

Indication Dose Duration Notes

H. pylori eradication (non-standard regimen) 1 tablet (500 mg + 600 mg) BD 14 days OFF-LABEL; Specialist only. Used where metronidazole resistance suspected. Evidence: Indian specialist practice; alternative when first-line clarithromycin-based regimens fail or unavailable

PAEDIATRIC DOSING (Specialist Only)

Primary Indications: Mixed Bacterial and Protozoal Infections

⚠️ Fixed-dose combination tablets NOT suitable for children <12 years due to inability to adjust individual component doses

Age/Weight Dose Duration Notes

≥12 years or ≥40 kg 1 tablet (250 mg + 300 mg) BD OR 1 tablet (500 mg + 600 mg) BD depending on severity 5–7 days Monitor for GI intolerance; ensure adequate hydration

<12 years or <40 kg Use separate components only As per individual drug Refer to individual amoxicillin and metronidazole/tinidazole paediatric dosing

Minimum age for FDC use: 12 years

Safety monitoring:

• GI tolerance assessment

• Signs of allergic reaction (rash, urticaria)

• Neurological symptoms (tinidazole-related)

Secondary Indications — Paediatrics (Off-label)

Not recommended. Individual components (amoxicillin suspension + metronidazole suspension) should be used separately under specialist guidance for any off-label paediatric indications.

30 No dose adjustment required

10–30 Use with caution; extend dosing interval from BD to OD

<10 or on dialysis Avoid fixed-dose combination; use individual agents with appropriate dose adjustments

Note: Tinidazole is partially renally excreted; accumulation risk in severe renal impairment may increase CNS adverse effects.

• Known hypersensitivity to amoxicillin, any penicillin, or nitroimidazole class drugs

• History of tinidazole/metronidazole-associated peripheral neuropathy or seizures

• Severe hepatic impairment

• First trimester of pregnancy

• Concurrent disulfiram therapy

• Blood dyscrasias (active or history of)

• Seizure disorders (tinidazole may lower seizure threshold)

• History of antibiotic-associated diarrhoea or Clostridioides difficile colitis

• Prolonged QTc interval or concurrent QT-prolonging medications

• Active alcohol consumption (advise strict abstinence during and 72 hours after therapy)

• Concurrent use of CNS depressants

• Infectious mononucleosis (risk of amoxicillin-induced rash)

• Patients with renal impairment (dose interval adjustment needed)

Aspect Recommendation

Overall safety Avoid in first trimester; use with caution in second/third trimester only if clearly indicated

Amoxicillin Generally considered safe (Pregnancy Category B equivalent)

Tinidazole Crosses placenta; avoid in first trimester; limited safety data for later trimesters

Preferred alternatives Amoxicillin alone; Amoxicillin + Metronidazole (short course, second/third trimester); Cefixime for bacterial coverage

When to use Only if benefit clearly outweighs risk; under obstetrician guidance

Monitoring Maternal liver function; fetal growth if prolonged use

Aspect Recommendation

Compatibility Generally avoid during breastfeeding

Amoxicillin Compatible with breastfeeding; excreted in low amounts

Tinidazole Excreted in breast milk in moderate concentrations; theoretical concern for carcinogenicity in animal studies

Preferred alternatives Amoxicillin alone; Metronidazole short-course if anaerobic coverage essential (pump and discard for 12–24 hours after last dose)

Infant monitoring Diarrhoea, oral thrush, feeding intolerance, irritability

• Starting dose: Use lower strength (250 mg + 300 mg) if available; otherwise, standard dose with close monitoring

• Titration: Not typically required; short-course therapy preferred

• Special considerations:

• Assess renal function before initiating; adjust interval if eGFR 10–30

• Higher risk of GI intolerance, dizziness, and confusion (tinidazole-related)

• Monitor for signs of peripheral neuropathy

• Increased fall risk due to dizziness

• Ensure adequate hydration

Drug Interaction Management

Warfarin Tinidazole inhibits warfarin metabolism → increased bleeding risk Monitor INR closely; may need warfarin dose reduction

Disulfiram Risk of acute psychosis Contraindicated — do not co-administer

Alcohol Disulfiram-like reaction (flushing, nausea, vomiting, hypotension, tachycardia) Contraindicated — avoid alcohol during and 72 hours after therapy

Lithium Amoxicillin may increase lithium levels Monitor lithium levels

Live vaccines (oral typhoid, cholera) Antibiotics reduce vaccine efficacy Complete antibiotic course before vaccination or delay vaccination

Drug Interaction Management

Oral contraceptives Amoxicillin may reduce efficacy (theoretical, controversial) Advise additional barrier contraception during therapy

Carbamazepine Tinidazole may inhibit metabolism → increased carbamazepine levels Monitor for toxicity (ataxia, nystagmus)

Phenytoin Mutual alteration of drug levels Monitor phenytoin levels if concurrent use unavoidable

Cimetidine Reduces tinidazole metabolism → increased CNS effects Avoid combination if possible; monitor for neurological symptoms

Rifampicin Induces amoxicillin metabolism → reduced efficacy Use alternative antibiotic if on rifampicin-based TB therapy

Methotrexate Amoxicillin reduces renal clearance of methotrexate Monitor for methotrexate toxicity; avoid if possible

• Metallic or bitter taste (tinidazole)

• Nausea and vomiting

• Diarrhoea

• Abdominal discomfort or cramping

• Headache

• Dizziness

• Skin rash (amoxicillin)

• Vaginal candidiasis (especially with prolonged use)

• Dark-coloured urine (harmless; tinidazole metabolite)

• Anaphylaxis / severe hypersensitivity reaction — requires immediate discontinuation and emergency management

• Stevens-Johnson Syndrome / Toxic Epidermal Necrolysis — rare; discontinue immediately

• Seizures — especially with tinidazole overdose or hepatic impairment

• Peripheral neuropathy — with prolonged tinidazole use; requires discontinuation

• Cholestatic jaundice / hepatitis — discontinue and investigate

• Antibiotic-associated colitis (C. difficile) — discontinue; initiate appropriate therapy

• Blood dyscrasias (leukopenia, thrombocytopenia) — rare

Early (within 3–5 days) GI tolerance; neurological symptoms (paraesthesias, ataxia); allergic manifestations

Long-term (if >7 days) LFTs; CBC; signs of peripheral neuropathy; stool examination for treatment response

If on warfarin INR at baseline and 3–5 days after starting therapy

• ALMOX-TZ (Alkem)

• NOVAMOX-TZ (Cipla)

• BIOMOX-TZ

• MOX-TZ

• AMOXIL-TZ

• CLAMP-TZ

• Multiple branded generics available across India

(Note: ZIFI-TZ contains Cefixime + Tinidazole, NOT Amoxicillin + Tinidazole)

Strength Price Range

• NPPA status: Not under price control

• Availability: Widely available in private sector; not routinely stocked in government supply lists

1. Alcohol avoidance is essential — counsel patients to abstain during therapy and for at least 72 hours after the last dose to prevent disulfiram-like reaction

1. Not suitable for paediatric use — fixed-dose tablets cannot be split accurately; use separate amoxicillin and metronidazole suspensions in children <12 years

1. Duration should not exceed 7–10 days — prolonged tinidazole exposure increases risk of peripheral neuropathy

1. Metallic taste is expected — pre-warn patients to improve adherence; suggest taking with food or flavoured beverages

1. Consider metronidazole-based alternatives when tinidazole is contraindicated or in pregnancy/lactation

1. Not appropriate for uncomplicated bacterial diarrhoea — reserve for suspected mixed infections with protozoal component

amoxicillin; tinidazole; FDC; amoebiasis; giardiasis; dental infection; anaerobic infection; protozoal infection; Schedule H; avoid-in-pregnancy; avoid-in-lactation; paediatric-not-suitable

RxIndia v1.0 — 04 Jan 2025

• CDSCO Approved Drug Formulations List

• Indian Pharmacopoeia (IP)

• API Textbook of Medicine (2022)

• AIIMS Standard Treatment Guidelines

• Indian Dental Association Clinical Protocols

• ICMR Guidelines on Management of Diarrhoeal Diseases

• IAP Drug Formulary (for paediatric exclusion guidance)

• Goodman & Gilman's The Pharmacological Basis of Therapeutics (supportive)