Drug Action
Metronidazole is an antimicrobial drug with high activity against anaerobic bacteria and protozoa.
Source page 594
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Individual generic drug information
Extracted information for Metronidazole only.
Metronidazole is an antimicrobial drug with high activity against anaerobic bacteria and protozoa.
Source page 594
Anaerobic infections ▶BY MOUTH ▶Child 1 month: 7.5 mg/kg every 12 hours usually treated for 7 days (for 10–14 days in Clostridioides difficile infection) ▶Child 2 months–11 years: 7.5 mg/kg every 8 hours (max. per dose 400 mg) usually treated for 7 days (for 10–14 days in Clostridioides difficile infection) ▶Child 12–17 years: 400 mg every 8 hours usually treated for 7 days (for 10–14 days in Clostridioides difficile infection) ▶Adult: 400 mg every 8 hours, alternatively 500 mg every 8 hours usually treated for 7 days (for 10–14 days in Clostridioides difficile infection) ▶BY RECTUM ▶Child 1–11 months: 125 mg 3 times a day for 3 days, then 125 mg twice daily, for usual total treatment duration of 7 days ▶Child 1–4 years: 250 mg 3 times a day for 3 days, then 250 mg twice daily, for usual total treatment duration of 7 days ▶Child 5–9 years: 500 mg 3 times a day for 3 days, then 500 mg twice daily, for usual total treatment duration of 7 days ▶Child 10–17 years: 1 g 3 times a day for 3 days, then 1 g twice daily, for usual total treatment duration of 7 days ▶Adult: 1 g 3 times a day for 3 days, then 1 g twice daily, for usual total treatment duration of 7 days ▶BY INTRAVENOUS INFUSION ▶Adult: 500 mg every 8 hours usually treated for 7 days (for 10–14 days in Clostridioides difficile infection), to be given over 20 minutes Moderate diabetic foot infection | Severe diabetic foot infection | Leg ulcer infection [in combination with other drugs] ▶BY MOUTH ▶Adult: 400 mg every 8 hours ▶BY INTRAVENOUS INFUSION ▶Adult: 500 mg every 8 hours Cellulitis | Erysipelas ▶BY MOUTH ▶Child 1 month: 7.5 mg/kg every 12 hours for 7 days then review ▶Child 2 months–11 years: 7.5 mg/kg every 8 hours (max. per dose 400 mg) for 7 days then review ▶Child 12–17 years: 400 mg every 8 hours for 7 days then review ▶Adult: 400 mg every 8 hours for 7 days then review ▶BY INTRAVENOUS INFUSION ▶Adult: 500 mg every 8 hours Helicobacter pylori eradication [in combination with other drugs (see Helicobacter pylori infection p. 89)] ▶BY MOUTH ▶Adult: 400 mg twice daily for 7 days for first- and second-line eradication therapy; 10 days for third-line eradication therapy Fistulating Crohn’s disease ▶BY MOUTH ▶Adult: 10–20 mg/kg daily in divided doses, usual dose 400–500 mg 3 times a day usually given for 1 month but no longer than 3 months because of concerns about peripheral neuropathy Acute diverticulitis [in combination with other drugs (see Diverticular disease and diverticulitis p. 40)] ▶BY MOUTH ▶Adult: 400 mg 3 times a day for 5 days then review ▶BY INTRAVENOUS INFUSION ▶Adult: 500 mg every 8 hours Pressure sores ▶BY MOUTH ▶Adult: 400 mg every 8 hours for 7 days Bacterial vaginosis (notably Gardnerella vaginalis infection) ▶BY MOUTH ▶Adult: 400–500 mg twice daily for 5–7 days, alternatively 2 g for 1 dose Bacterial vaginosis ▶BY VAGINA USING VAGINAL GEL ▶Adult: 1 applicatorful daily for 5 days, dose to be administered at night DOSE EQUIVALENCE AND CONVERSION ▶1 applicatorful of vaginal gel delivers a 5 g dose of metronidazole 0.75%. Pelvic inflammatory disease ▶BY MOUTH ▶Adult: 400 mg twice daily for 14 days Acute ulcerative gingivitis ▶BY MOUTH ▶Child 1–2 years: 50 mg every 8 hours for 3 days ▶Child 3–6 years: 100 mg every 12 hours for 3 days ▶Child 7–9 years: 100 mg every 8 hours for 3 days ▶Child 10–17 years: 200–250 mg every 8 hours for 3 days ▶Adult: 400 mg every 8 hours for 3 days Acute oral infections ▶BY MOUTH ▶Child 1–2 years: 50 mg every 8 hours for 3–7 days ▶Child 3–6 years: 100 mg every 12 hours for 3–7 days ▶Child 7–9 years: 100 mg every 8 hours for 3–7 days ▶Child 10–17 years: 200–250 mg every 8 hours for 3–7 days ▶Adult: 400 mg every 8 hours for 3–7 days Surgical prophylaxis ▶BY MOUTH ▶Adult: 400–500 mg, to be administered 2 hours before surgery, then 400–500 mg every 8 hours if required for up to 3 doses (in high-risk procedures) ▶BY RECTUM ▶Adult: 1 g, to be administered 2 hours before surgery, then 1 g every 8 hours if required for up to 3 doses (in high-risk procedures) ▶BY INTRAVENOUS INFUSION ▶Adult: 500 mg, to be administered up to 30 minutes before the procedure (if rectal administration inappropriate), then 500 mg every 8 hours if required for up to 3 further doses (in high-risk procedures) Invasive intestinal amoebiasis | Extra-intestinal amoebiasis (including liver abscess) ▶BY MOUTH ▶Child 1–2 years: 200 mg 3 times a day for 5 days in intestinal infection (for 5–10 days in extra-intestinal infection) ▶Child 3–6 years: 200 mg 4 times a day for 5 days in intestinal infection (for 5–10 days in extra-intestinal infection) ▶Child 7–9 years: 400 mg 3 times a day for 5 days in intestinal infection (for 5–10 days in extra-intestinal infection) ▶Child 10–17 years: 800 mg 3 times a day for 5 days in intestinal infection (for 5–10 days in extra-intestinal infection) ▶Adult: 800 mg 3 times a day for 5 days in intestinal infection (for 5–10 days in extra-intestinal infection) Urogenital trichomoniasis ▶BY MOUTH ▶Child 1–2 years: 50 mg 3 times a day for 7 days ▶Child 3–6 years: 100 mg twice daily for 7 days ▶Child 7–9 years: 100 mg 3 times a day for 7 days ▶Child 10–17 years: 200 mg 3 times a day for 7 days, alternatively 400–500 mg twice daily for 5–7 days, alternatively 2 g for 1 dose ▶Adult: 200 mg 3 times a day for 7 days, alternatively 400–500 mg twice daily for 5–7 days, alternatively 2 g for 1 dose Giardiasis ▶BY MOUTH ▶Child 1–2 years: 500 mg once daily for 3 days ▶Child 3–6 years: 600–800 mg once daily for 3 days ▶Child 7–9 years: 1 g once daily for 3 days ▶Child 10–17 years: 2 g once daily for 3 days, alternatively 400 mg 3 times a day for 5 days, alternatively 500 mg twice daily for 7–10 days ▶Adult: 2 g once daily for 3 days, alternatively 400 mg 3 times a day for 5 days, alternatively 500 mg twice daily for 7–10 days Established case of tetanus ▶BY INTRAVENOUS INFUSION ▶Adult: (consult product literature) l UNLICENSED USE g Metronidazole is used for the treatment of cellulitis, h but is not licensed for this indication. g Metronidazole is used for the treatment of erysipelas, h but is not licensed for this indication. ▶With systemic use in adults Metronidazole doses in the BNF may differ from those in product literature. g Combination regimens and durations for Helicobacter pylori eradication may differ from product literature but adhere to national guidelines. h
Source pages 594, 595
▶With vaginal use Not recommended during menstruation. some systemic absorption may occur with vaginal gel
Source page 595
For choice of antibacterial therapy, see Antibacterials, use for prophylaxis p. 529, Antiprotozoal drugs p. 641, Diabetic foot infections, antibacterial therapy p. 533, Gastro- intestinal system infections, antibacterial therapy p. 535, Genital system infections, antibacterial therapy p. 536, Helicobacter pylori infection p. 89, Oropharyngeal infections, antibacterial therapy p. 1282, Skin infections, antibacterial therapy p. 540. ▶With systemic use Metronidazole is well absorbed orally and the intravenous route is normally reserved for severe infections. Metronidazole by the rectal route is an effective alternative to the intravenous route when oral administration is not possible.
Source page 595
Extracted information for Metronidazole only.
→Appendix 1: metronidazole
Source page 595
▶Common or very common ▶With systemic use Dry mouth. myalgia. nausea. oral disorders. taste metallic. vomiting ▶With vaginal use Pelvic discomfort. vulvovaginal candidiasis . vulvovaginal disorders ▶Uncommon ▶With systemic use Asthenia. headache. leucopenia (with Infection long term or intensive therapy) ▶With vaginal use Menstrual cycle irregularities. vaginal haemorrhage ▶Rare or very rare ▶With systemic use Agranulocytosis. angioedema. appetite decreased. ataxia. cerebellar syndrome. confusion. diarrhoea. dizziness. drowsiness. encephalopathy. epigastric pain. epileptiform seizure (with long term or intensive therapy). flushing. hallucination. hepatic disorders. meningitis aseptic. mucositis. nerve disorders. neutropenia. pancreatitis. pancytopenia. peripheral neuropathy (with long term or intensive therapy). psychotic disorder. seizure. severe cutaneous adverse reactions (SCARs). skin reactions. thrombocytopenia. urine dark. vision disorders ▶Frequency not known ▶With systemic use Depressed mood. gastrointestinal disorder. hearing impairment. taste altered. tinnitus
Source page 595
▶With systemic use Manufacturer advises avoidance of high- dose regimens; use only if potential benefit outweighs risk.
Source page 595
▶With systemic use Significant amount in milk; manufacturer advises avoid large single doses though otherwise compatible; may give milk a bitter taste.
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▶With oral use or rectal use Manufacturer advises caution in hepatic encephalopathy (risk of decreased clearance). ▶With intravenous use Manufacturer advises caution in severe impairment (risk of decreased clearance). Dose adjustments ▶With oral use or rectal use Manufacturer advises dose reduction to one-third of the daily dose in hepatic encephalopathy (dose may be given once daily). ▶With intravenous use Manufacturer advises consider dose reduction in severe impairment.
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▶With systemic use Clinical and laboratory monitoring advised if treatment exceeds 10 days.
Source page 595
Extracted information for Metronidazole only.
▶With intravenous use For intravenous infusion, give over 20–30 minutes.
Source page 595
There can be variation in the licensing of different medicines containing the same drug. Forms available from special-order manufacturers include: oral suspension, oral solution, suppository Tablet CAUTIONARY AND ADVISORY LABELS 4, 9, 21, 25, 27 ▶Metronidazole (Non-proprietary) Metronidazole 200 mg Metronidazole 200mg tablets | 21 tablet P £4.03 DT = £4.03 Infection Metronidazole 400 mg Metronidazole 400mg tablets | 21 tablet P £5.75 DT = £3.75 Metronidazole 500 mg Metronidazole 500mg tablets | 21 tablet P £39.29 DT = £39.29 ▶Flagyl (Sanofi) Metronidazole 200 mg Flagyl 200mg tablets | 21 tablet P £4.49 DT = £4.03 Metronidazole 400 mg Flagyl 400mg tablets | 14 tablet P £6.34 Suppository CAUTIONARY AND ADVISORY LABELS 4, 9 ▶Flagyl (Sanofi) Metronidazole 500 mg Flagyl 500mg suppositories | 10 suppository P £15.18 DT = £15.18 Metronidazole 1 gram Flagyl 1g suppositories | 10 suppository P £23.06 DT = £23.06 Oral suspension CAUTIONARY AND ADVISORY LABELS 4, 9 ▶Metronidazole (Non-proprietary) Metronidazole (as Metronidazole benzoate) 40 mg per 1 ml Metronidazole 200mg/5ml oral suspension | 100 ml P £37.29 DT = £37.29 Vaginal gel EXCIPIENTS: May contain Disodium edetate, hydroxybenzoates (parabens), propylene glycol ▶Zidoval (Mylan) Metronidazole 7.5 mg per 1 gram Zidoval 0.75% vaginal gel | 40 gram P £4.31 DT = £4.31 Infusion ELECTROLYTES: May contain Sodium ▶Metronidazole (Non-proprietary) Metronidazole 5 mg per 1 ml Metronidazole 500mg/100ml infusion 100ml bags | 20 bag P £67.05 DT = £67.05
Source page 596
Extracted information for Metronidazole only.
Medicines for Children leaflet: Metronidazole for bacterial infections www.medicinesforchildren.org.uk/metronidazole- bacterial-infections l PROFESSION SPECIFIC INFORMATION Dental practitioners’ formulary ▶With oral use Metronidazole Tablets may be prescribed. Metronidazole Oral Suspension may be prescribed.
Source page 595
Filter the extracted dose blocks for this individual drug.
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7.5 mg/kg every 12 hours usually treated
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Candidate age grouping · source page 594
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7.5 mg/kg every 8 hours (max.
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Candidate age grouping · source page 594
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400 mg every 8 hours usually treated
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Candidate age grouping · source page 594
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400 mg every 8 hours, alternatively 500 mg every
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Candidate age grouping · source page 594
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125 mg 3 times a day for 3 days, then
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Candidate age grouping · source page 594
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250 mg 3 times a day for 3 days, then
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Candidate age grouping · source page 594
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500 mg 3 times a day for 3 days, then
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Candidate age grouping · source page 594
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1 g 3 times a day for 3 days, then 1 g
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Candidate age grouping · source page 594
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1 g 3 times a day for 3 days, then 1 g twice daily,
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Candidate age grouping · source page 594
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500 mg every 8 hours usually treated for 7 days
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Candidate age grouping · source page 594
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400 mg every 8 hours
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Candidate age grouping · source page 594
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500 mg every 8 hours
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Candidate age grouping · source page 594
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7.5 mg/kg every 12 hours for 7 days then
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Candidate age grouping · source page 594
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7.5 mg/kg every 8 hours (max.
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Candidate age grouping · source page 594
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400 mg every 8 hours for 7 days then
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Candidate age grouping · source page 594
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400 mg every 8 hours for 7 days then review
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Candidate age grouping · source page 594
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500 mg every 8 hours
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Candidate age grouping · source page 594
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400 mg twice daily for 7 days for first- and
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10–20 mg/kg daily in divided doses, usual dose
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400 mg 3 times a day for 5 days then review
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Candidate age grouping · source page 594
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500 mg every 8 hours
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Candidate age grouping · source page 594
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400 mg every 8 hours for 7 days
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Candidate age grouping · source page 594
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400–500 mg twice daily for 5–7 days,
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Candidate age grouping · source page 594
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1 applicatorful daily for 5 days, dose to be
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Candidate age grouping · source page 594
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400 mg twice daily for 14 days
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Candidate age grouping · source page 594
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50 mg every 8 hours for 3 days
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Candidate age grouping · source page 594
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100 mg every 12 hours for 3 days
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Candidate age grouping · source page 594
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100 mg every 8 hours for 3 days
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Candidate age grouping · source page 594
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200–250 mg every 8 hours for 3 days
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Candidate age grouping · source page 594
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400 mg every 8 hours for 3 days
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Candidate age grouping · source page 594
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50 mg every 8 hours for 3–7 days
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Candidate age grouping · source page 594
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100 mg every 12 hours for 3–7 days
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Candidate age grouping · source page 594
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100 mg every 8 hours for 3–7 days
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Candidate age grouping · source page 594
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200–250 mg every 8 hours for
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Candidate age grouping · source page 594
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400 mg every 8 hours for 3–7 days
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Candidate age grouping · source page 594
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400–500 mg, to be administered 2 hours before
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Candidate age grouping · source page 595
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1 g, to be administered 2 hours before surgery,
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Candidate age grouping · source page 595
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500 mg, to be administered up to 30 minutes
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Candidate age grouping · source page 595
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200 mg 3 times a day for 5 days in
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200 mg 4 times a day for 5 days in
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400 mg 3 times a day for 5 days in
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Candidate age grouping · source page 595
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800 mg 3 times a day for 5 days in
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Candidate age grouping · source page 595
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800 mg 3 times a day for 5 days in intestinal
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Candidate age grouping · source page 595
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50 mg 3 times a day for 7 days
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Candidate age grouping · source page 595
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100 mg twice daily for 7 days
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Candidate age grouping · source page 595
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100 mg 3 times a day for 7 days
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Candidate age grouping · source page 595
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200 mg 3 times a day for 7 days,
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Candidate age grouping · source page 595
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200 mg 3 times a day for 7 days, alternatively
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Candidate age grouping · source page 595
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500 mg once daily for 3 days
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Candidate age grouping · source page 595
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600–800 mg once daily for 3 days
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Candidate age grouping · source page 595
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1 g once daily for 3 days
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Candidate age grouping · source page 595
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2 g once daily for 3 days, alternatively
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2 g once daily for 3 days, alternatively 400 mg
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Candidate age grouping · source page 595
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(consult product literature)
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Candidate age grouping · source page 595