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Citywest Business Campus, Dublin 24, Ireland
Telephone: +353 1 4035600
Fax: +353 1 4035687
Medical Information e-mail: iemedinfo@sanofi.com

Summary of Product Characteristics last updated on medicines.ie: 22/12/2016
SPC Flagyl-S 200mg/5ml Oral Suspension

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Flagyl-S 200mg/5ml Oral Suspension.

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Each 5 ml of Suspension contains Metronidazole Benzoate equivalent to 200 mg of Metronidazole.


Each 5ml also contains 3.01g sucrose, 4.00mg methyl parahydroxybenzoate, 1.00mg propyl parahydroxybenzoate and 0.04ml ethanol.

For a full list of excipients, see section 6.1.

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Oral Suspension.

A white to cream-yellow oral suspension easily redispersible with gentle shaking.

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4.1 Therapeutic indications

Metronidazole is indicated in adults and children for the following indications:

In the treatment of urogenital trichomonaisis.

In the treatment of acute ulcerative gingivitis.

In the treatment of infections due to E. histolytica (including carrier states).

In the treatment of infections due to G. Lamblia (including carrier states).

In the prevention and treatment of infections due to anaerobic bacteria, particularly species of Bacteroides, anaerobic Streptococci, fusobacteria, clostridia, etc.

In the treatment of acute dental infections.

In the treatment of non-specific vaginitis.

Metronidazole is indicated in adults only for the following indications:

In the treatment of chronic pressure sores and ulcers with possible infection due to anaerobes.

Consideration should be given to official guidance on the appropriate use of antibacterial agents.

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4.2 Posology and method of administration


Recommended Dosage:

1. Urogential trichomoniasis

Adults and children over 10 years:

2000mg as a single dose or 200 mg 3 times daily for 7 days or 400mg twice daily for 5-7 days

Children < 10 years:

40mg/kg orally as a single dose or 15 -30 mg/kg/day divided in 2-3 doses for 7 days; not to exceed 2000mg/dose

2. Acute ulcerative gingivitis

Adults & Children over 10 years:

600 mg daily in 3 divided doses for 3 days.


Aged 7 to 10 years:

300 mg daily in 3 divided doses for 3 days.

Aged 3 to 7 years:

200 mg daily in 2 divided doses for 3 days.

Aged 1 to 3 years:

150 mg in 3 divided doses for 3 days.

3. Amoebiasis

Adults and children over 10 years:

400 to 800mg 3 times daily for 5-10 days.


Aged 7 to 10 years:

200 to 400 mg 3 times daily for 5-10 days

Aged 3 to 7 years:

100 to 200 mg 4 times daily for 5-10 days

Aged 1 to 3 years:

100 to 200mg 3 times daily for 5-10 days.

Alternatively, doses may be expressed by body weight:

35 to 50mg/kg daily in 3 divided doses for 5 to 10 days, not to exceed 2400 mg/day

4. Giardiasis

Adults and children over 10 years:

2000 mg once daily for 3 days, or 400mg three times daily for 5 days, or 500mg twice daily for 7 to 10 days.


Aged 7 to 10 years:

1000 mg once daily for 3 days.

Aged 3 to 7 years:

600 mg to 800mg once daily for 3 days.

Aged 1 to 3 years:

500 mg once daily for 3 days.

Alternatively, as expressed in mg per kg of body weight: 15-40 mg/kg/day divided in 2- 3 doses.

5. Anaerobic infections



800 mg followed by 400 mg 8 hourly.

Children: Children > 8 weeks to 12 years of age: The usual daily dose is 20-30mg/kg/day as a single dose or divided into 7.5mg/kg every 8 hours. The daily dose may be increased to 40mg/kg, depending on the severity of the infection. Duration of treatment is usually 7 days.

Children < 8 weeks of age: 15mg/kg as a single dose daily or divided into 7.5mg/kg every 12 hours.

In newborns with a gestation age < 40 weeks, accumulation of metronidazole can occur during the first week of life, therefore the concentrations of metronidazole in serum should preferably be monitored after a few days therapy.

Prophylaxis against postoperative infections caused by anaerobic bacteria:


400 mg at 8 hourly intervals during the 24 hours immediately preceding operation, followed post operatively by intravenous or rectal administration until oral dosing can be resumed.


Children < 12 years: 20-30 mg/kg as a single dose given 2-3 hours before surgery

Newborns with a gestation age <40 weeks: 10mg/kg body weight as a single dose 2-3 hours before operation

Eradication of helicobacter pylori in paediatric patients:

As part of a combination therapy, 20mg/kg/day not to exceed 500mg twice daily for 7- 14 days. Official guidelines should be consulted before initiating therapy.

6. Dental Infections

The usual total daily dose is 600 to 800 mg in divided doses. Treatment should generally be continued for 3 to 7 days.

7. Chronic pressure sores and ulcers


1200 mg daily in 3 divided doses.

8. Bacterial Vaginitis

Adults and Adolescents:

A single dose of 2000mg may be used or 400 mg twice daily for 5-7 days.

Adjustment of dosage does not appear necessary in patients with renal impairment.

In the case of children whose weights are below those usual for their age, or of infants below 10 kg in weight, dosage of metronidazole should be reduced proportionately.

Metronidazole is removed during haemodialysis and should be administered after the procedure is finished.


Caution is advised particularly at high doses. No information is available on modification of dosage.

Hepatic Encephalopathy

Daily dosage should be reduced to one third and may be given once daily (see precautions).

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4.3 Contraindications

Metronidazole should be used with caution in patients with active or chronic severe peripheral and cenral nervous system diseases due to the risk of neurological aggravation.

Use in patients with known hypersensitivity to metronidazole.

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4.4 Special warnings and precautions for use

The use of Flagyl for prolonged treatment duration should be carefully weighed. If prolonged therapy is required, the physician should bear in mind the possibility of peripheral neuropathy or leucopenia. Both effects are usually reversible. It is recommended that haematological tests be carried out regularly and that patients should be monitored for adverse reactions such as peripheral or central neuropathy (such as paraesthesia, ataxia, dizziness, convulsive seizures).

High dosage regimens have been associated with transient epileptiform seizures. Caution is required in patients with active disease of the central nervous system except for brain abscess.

Metronidazole and a metabolite have been shown to be mutagenic in some tests with non mammalian cells.

Intensive or prolonged metronidazole therapy should be conducted only under conditions of close surveillance for clinical and biological effects and under specialist direction.

Metronidazole is removed during haemodialysis and should be administered after the procedure is finished.

Metronidazole is mainly metabolised by hepatic oxidation. Substantial impairment of metronidazole clearance may occur in the presence of advanced hepatic insufficiency. The risk/benefit using metronidazole to treat trichomoniasis in such patients should be carefully considered.

Flagyl should be administered with caution to patients with hepatic encephalopathy.

Cases of severe bullous skin reactions, sometimes fatal, such as Stevens-Johnson syndrome or toxic epidermal necrolysis have been reported with metronidazole (see Section 4.8). The majority of cases of SJS reported occurred within 7 weeks of starting treatment with metronidazole. Patients should be advised of the signs and symptoms and monitored closely for skin reactions. If symptoms of SJS or TEN (e.g. flu-like symptoms, progressive skin rash often with blisters or mucosal lesions) are present, treatment should be discontinued (see 4.8 Undesirable Effects).

Patients should be warned that metronidazole may darken urine (due to metronidazole metabolite).

Patients should be advised not to take alcohol during metronidazole therapy and for at least 48 hours afterwards (see section 4.5 Interaction with other medicinal products and other forms of interaction).

Cases of severe hepatotoxicity/acute hepatic failure, including cases with a fatal outcome with very rapid onset after treatment initiation in patients with Cockayne syndrome have been reported with products containing metronidazole for systemic use. In this population, metronidazole should therefore be used after careful benefit-risk assessment and only if no alternative treatment is available. Liver function tests must be performed just prior to the start of therapy, throughout and after end of treatment until liver function is within normal ranges, or until the baseline values are reached. If the liver function tests become markedly elevated during treatment, the drug should be discontinued.

Patients with Cockayne syndrome should be advised to immediately report any symptoms of potential liver injury to their physician and stop taking metronidazole.

This medicinal product contains small amounts of ethanol (alcohol), less than 100mg per 5ml dose.

Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine.

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4.5 Interaction with other medicinal products and other forms of interaction

Potentiation of the anticoagulant effect and increased hemorrhagic risk caused by decreased hepatic catabolism. In case of coadministration, prothrombin time should be more frequently monitored and anticoagulant therapy adjusted during treatment with metronidazole.

Patients should be advised not to take alcohol, (or drugs containing alcohol) during Metronidazole therapy and for at least 48 hours afterwards because of a disulfiram like (antabuse effect) reaction (flushing, vomiting, tachycardia).

Disulfiram: psychotic reactions have been reported in patients who were using metronidazole and disulfiram concurrently.

Lithium retention observed by increased plasma lithium levels, accompanied by evidence of possible renal damage has been reported in patients treated simultaneously with lithium and metronidazole. Plasma levels of lithium may be increased by metronidazole. Lithium treatment should be tapered or withdrawn before administering metronidazole. Plasma concentration of lithium, creatinine and electrolytes should be monitored in patients under treatment with lithium while they receive metronidazole.

Phenytoin or Phenobarbital: increased elimination of metronidazole resulting in reduced plasma levels. A similar effect may occur with other drugs which induce hepatic microsomal enzymes.

Cyclosporin: risk of elevation of the cyclosporin serum levels. Serum cyclosporine and serum creatinine should be closely monitored when coadministration is necessary.

5 Fluorouracil: reduced clearance of 5 fluorouracil resulting in increased toxicity of 5 fluorouracil.

Busulfan: Plasma levels of busulfan may be increased by metronidazole, which may lead to severe busulfan toxicity.

4.6 Pregnancy and lactation

Metronidazole should only be used during pregnancy or lactation following careful evaluation and only if considered essential by the physician. Its effects on foetal organogenesis are not known. If used, high dosage regimens should be avoided. The drug crosses the placenta and is excreted in breast milk in which concentrations equal those in serum. Unnecessary exposure to the drug should be avoided.

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4.7 Effects on ability to drive and use machines

Patients should be warned about the potential for confusion, dizziness, hallucinations, convulsions or eye disorders (see section 4.8 Undesirable effects) and advised not to drive or operate machinery if these symptoms occur.

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4.8 Undesirable effects

Frequency, type and severity of adverse reactions in children are the same as in adults.

Gastrointestinal disorders

- epigastric pain, nausea, vomiting, malaise, diarrhoea.

- oral mucositis, taste disorders, dry mouth, anorexia.

- reversible cases of pancreatitis.

- tongue discolouration/furry tongue.

Immune system disorders

- angioedema anaphylactic shock.

Nervous system disorders

- peripheral sensory neuropathy, paraesthesia

- headache, convulsions, dizziness.

- reports of encephalopathy (e.g. confusion) and subacute cerebellar syndrome (e.g. ataxia, dysathria, gait impairment, nystagmus and tremor) which may resolve with discontinuation of the drug.

- aseptic meningitis

Psychiatric disorders

- psychotic disorders including confusion, hallucinations

- depressed mood

Eye disorders

- transient vision disorders such as diplopia, myopia, blurred vision, decreased visual acuity, changes in color vision.

- Optic neuropathy/neuritis.

Ear and labyrinth disorders

- hearing impaired/hearing loss (including sensorineural)

- tinnitus

Blood and lymphatic system disorders

- cases of agranulocytosis, neutropenia and thrombocytopenia have been reported.

Hepatobiliary disorders

- increase in liver enzymes (AST, ALT, alkaline phosphatase), cholestatic or mixed hepatitis and hepatocellular liver injury, sometimes with jaundice, have been reported.

- cases of liver failure requiring liver transplant have been reported in patients treated with metronidazole mostly when used in combination with other antibiotic drugs.

Skin and subcutaneous tissue disorders

- rash, pruritus, flushing, urticaria

- pustular eruptions

- fixed drug eruption

- Stevens-Johnson syndrome, toxic epidermal necrolysis.

General disorders and administration site conditions

- fever

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via HPRA Pharmacovigilance, Earlsfort Terrace, IRL - Dublin 2; Tel: +353 1 6764971; Fax: +353 1 6762517. Website: www.hpra.ie; e-mail: medsafety@hpra.ie

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4.9 Overdose

Single oral doses of metronidazole, up to 12g have been reported in suicide attempts and accidental overdoses. Symptoms were limited to vomiting, ataxia and slight disorientation. There is no specific antidote for metronidazole overdosage. In cases of suspected massive overdosage, a symptomatic and supportive treatment should be instituted.

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5.1 Pharmacodynamic properties

Metronidazole has antiprotozoal and antibacterial actions including activity against anaerobic bacteria and entamoeba histolytica.

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5.2 Pharmacokinetic properties

A nitroimidazole derivative well absorbed and widely distributed in the body. It is metabolised by hepatic acid oxidation, hydroxylation and glucuronidation and excreted in urine and faeces with a T½ of about 6-10 hours.

After a 400 mg metronidazole (or equivalent) single oral dose, given either as metronidazole benzoate 6.4% suspension or metronidazole tablet to 10 healthy subjects in a cross-over study (Table 1), tmax is delayed by approximately 2 hours, Cmax decreased by 45% and AUC by 20% corresponding to a decrease in relative bioavailability of 20% of the metronidazole benzoate 6.4 % oral suspension compared to the tablet. No change in elimination half-life is reported. No metronidazole benzoate was found in plasma.

These slight differences in the rate and extent of metronidazole absorption are due to the transformation of metronidazole benzoate to the active compound metronidazole by hydrolysation in the gastrointestinal tract.

Table 1 - Plasma metronidazole pharmacokinetic parameters after a single oral dose of metronidazole benzoate 6.4% suspension (400 mg metronidazole-equivalent) or metronidazole tablet (400 mg) to healthy male subjects (n=10)

Pharmacokinetic parameter

Metronidazole benzoate 6.4 % oral suspension

Metronidazole 400 mg tablet

Tmax (h)



Cmax (µg/mL)






Elimination half-life (h)



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5.3 Preclinical safety data

Metronidazole has been shown to be carcinogenic in the mouse and in the rat. However, similar studies in the hamster have given negative results and epidemiological studies in humans have provided no evidence of an increased carcinogenic risk in humans.

Metronidazole has been shown to be mutagenic in bacteria in vitro. In studies conducted in mammalian cells in vitro as well as in rodent or humans in vivo, there was inadequate evidence of a mutagenic effect of metronidazole, with some studies reporting mutagenic effects, while other studies were negative.

Therefore, the use of Flagyl for prolonged treatment duration should be carefull weighed (see section 4.4 “ Warnings and Precautions”.)

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6.1 List of excipient(s)



Sodium Dihydrogen Phosphate Dihydrate

Aluminium Magnesium Silicate

Methyl Parahydroxybenzoate (E218)

Propyl Parahydroxybenzoate (E216)

Ethanol 96% v/v

Lemon No.1 NA (includes Propylene glycol)

Orange Oil Terpeneless

Purified Water

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6.2 Incompatibilities

Not applicable.

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6.3 Shelf life

Unopened: 3 years.

After opening discard any unused suspension after 28 days.

Flagyl-S Suspension may be diluted, if necessary, with Syrup BP. The diluted suspension has a shelf life of 14 days.

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6.4 Special precautions for storage

Do not store above 25°C. Store in the original container to protect from light.

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6.5 Nature and contents of container

This product is supplied in amber, glass bottles with a pilfer proof aluminium cap with a polyvinylidene chloride liner or a polypropylene child proof cap with a polyethylene liner, containing 50, 100 or 125ml suspension.

Not all pack sizes may be marketed.

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6.6 Special precautions for disposal and other handling

No special requirements.

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sanofi-aventis Ireland Ltd. T/A SANOFI

Citywest Business Campus,

Dublin 24.

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PA 540/100/1

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1st April 1977 / 1st April 2007.

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December 2016.

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Active Ingredients

   Metronidazole benzoate