Metrogyl

Metronidazole.

FC tablet: Each film coated tablet contains: Metronidazole 200 mg / 400 mg.
Oral suspension: Each 5 ml (teaspoonful) contains: Metronidazole Benzoate equivalent to Metronidazole 200 mg.
Metrogyl (metronidazole) is an oral synthetic antiprotozoal and antibacterial agent, 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole.
Excipients/Inactive Ingredients: Oral suspension: Preservative: Methyl Paraben 5 mg, Propyl Paraben 5 mg.
Colour: Sunset Yellow.

Pharmacology: Mechanism of Action: Metronidazole diffuses into aerobic and anaerobic bacteria equally well, but in the former it remains unchanged while in the latter it is reduced. As a result of biochemical reduction in the cell, the concentration of unchanged drug is reduced and this probably creates a gradient which promotes further uptake of the drug into anaerobic organisms. The selective uptake and specificity of Metronidazole for anaerobes may be because their redox process are different from those aerobes; it has been assumed that the product of reduction of the nitro group of Metronidazole interacts with the DNA with ultimate inhibition of nucleic acid synthesis and subsequent cell death. Moreover Metronidazole has been shown to inhibit DNA synthesis and degrade existing DNA in Clostridium bifermentans.
FC tablet: The nitro group of Metronidazole is reduced in anaerobic bacteria and protozoa by the pyruvate phosphoroclastic reaction, in which the drug acts as a preferential electron acceptor. Oxygen markedly reduces the uptake of Metronidazole in experiments using certain anaerobic protozoa, suggesting that this process depends on reducing power inside the cell.
Oral suspension: The nitro group of Metronidazole accepts electrons from electron-transport proteins and diverts them from normal energy yielding pathways.
Pharmacokinetics: FC tablet: Disposition of Metronidazole in the body is similar for both oral and intravenous dosage forms, with an average elimination half-life in healthy humans of eight hours. The major route of elimination of Metronidazole and its metabolites is via the Urine (60 to 80% of the dose), with fecal excretion accounting for 6 to 15% of the dose. The metabolites that appear in the urine result primarily form side-chain oxidation (1-(beta hydroxyethyl)-2-hydroxymethyl-5-nitroimidazole and 2-methyl-5-nitroimidazole-1-yl-acetic acid) and glucuronide conjugation, with unchanged metronidazole accounting for approximately 20% of the total. Renal clearance of metronidazole is approximately 10ml/min/1.73 m². Metronidazole is the major component appearing in the plasma, with lesser quantities of the 2-hydroxymethyl metabolite also being present. Less than 20% of the circulating metronidazole is bound to plasma proteins. Both the parent compound and the metabolite process In vitro bactericidal activity against most strains of anerobic bacteria and in vitro trichomonacidal activity. Metronidazole appears in cerebrospinal fluid, saliva, and breast milk in concentrations similar to those found in plasma. Bactericidal concentrations of Metronidazole have also been detected in pus form hepatic abscesses. Following administration metronidazole is well absorbed with peak plasma concentrations occurring between one and two hours after administration. Plasma concentrations of Metronidazole are proportional to the administered dose. Oral administration 250 mg, 500 mg, or 2,000 mg produced peak plasma concentrations of bioavailability differences between males and females; however, because of weight differences, the resulting plasma levels in males are generally lower. Decreased renal function does not alter the single dose pharmacokinetics of metronidazole. However, plasma clearance of metronidazole is decreased patients with decreased liver function.
Oral suspension: Metronidazole is completely and promptly absorbed after oral administration. Half- life is about 8 Hrs, and its volume of distribution is approximately that of body water. About 10% of the drug is bound to plasma protein. Metronidazole penetrates well into body tissues and fluids. Therapeutics concentration is also achieved in the cerebrospinal fluid.
Both unchanged metronidazole & several metabolites are excreted in various proportions in the urine after oral administration of the parent compound. The liver is the main site of metabolism and this accounts for over 50% of the systemic clearance of Metronidazole. The 2 principal metabolites result from oxidation of side chains, both have antitrichomonal activity. The major route of elimination of Metronidazole and its metabolites is via the urine (60% to 80% of the dose) with faecal excretion accounting for 6% to 15% of the dose.
Decreased renal function does not alter the single dose pharmacokinetics of Metronidazole. However, plasma clearance of Metronidazole is decreased in patients with decreased liver function.

FC tablet: Symptomatic Trichomoniasis, Asymptomatic Trichomoniasis, Intestinal Amoebiasis, Amoebic Liver Abscess, Anaerobic Bacterial Infections, Intra-Abdominal Infections, Skin and Skin Structure Infections, Gynaecologic Infections, Bacterial Septicemia, Bone and Joint Infections, Central Nervous Systems (CNS) Infections, Lower Respiratory Tract Infections, Endocarditis.
Oral suspension: Amoebiasis, Giardiasis; Amoebic liver abscess; Anaerobic Bacterial Infections.

FC tablet: In elderly patients the pharmacokinetics of metronidazole may be altered and therefore monitoring of serum levels may be necessary to adjust the metronidazole dosages accordingly.
Trichomoniasis: Metronidazole is given orally either as a single 2-g dose, as a 2-day course of 800 mg in the morning and 1.2 g in the evening, or as a 7-day course of 600 mg to 1 g daily in two or three divided doses. Sexual partners should also be treated.
Amoebiasis: Metronidazole is given in oral doses of 400 to 800 mg three times daily for 5 to 10 days.
Anaerobic Bacterial Infections: The usual adult oral dosage is 7.5 mg/kg every six hours (approx. 500 mg for a 70 kg Adult). A maximum of 4 gm should not be exceeded during a 24 hour period.
The usual duration of therapy is 7 to 10 days; however, infections of the bone and joint, lower respiratory tract, and endocardium may require longer treatment.
Oral suspension: Children: 35 to 50 mg/kg/24 hours, divided into three doses, orally for 10 days.

FC tablet: Single oral doses of metronidazole, up to 15 g have been reported in suicide attempts and accidental overdoses. Symptoms reported include nausea, vomiting, and ataxia. Oral Metronidazole has been studied as a radiation sensitizer in the treatment of malignant tumors. Neurotoxic effects, including seizures and peripheral neuropathy, have been reported after 5 to 7 days of doses of 6 to 10.4 every other day.
Treatment: there is no specific antidote for metronidazole overdose: therefore management of the patient should consist of symptomatic and supportive therapy.

Metrogyl is contraindicated in patients with a prior history of hypersensitivity to metronidazole or other nitroimidazole derivatives.
FC tablet: In patients with trichomoniasis, Metrogyl is contraindicated during the first trimester of pregnancy.

FC tablet: Convulsive Seizures and Peripheral Neuropathy: Convulsive seizures and peripheral neuropathy, the later characterized mainly by numbness or paresthesia of an extremity, have been reported in patients treated with metronidazole. The appearance of abnormal neurologic signs demands the prompt discontinuation of Metrogyl therapy. Metrogyl should be administered with caution to patients with central nervous system diseases.

General: Patients with severe hepatic diseases metronidazole metabolizes slowly, with resultant accumulation of metronidazole and its metabolites in the plasma. Accordingly for such patients, doses below those usually recommended should be administered cautiously.
FC tablet: In known or previously recognized candidiasis Metrogyl may prevent more prominent symptoms during therapy and requires treatment with a candicidal agent.
Use in Pregnancy: Metronidazole crosses the placental barrier and enters the fetal circulation rapidly. Reproduction studies have been performed in rats at doses up to five times the human close and have revealed no evidence of impaired fertility or harm to the fetus due to Metronidazole.
Use in Lactation: Because of the potential for tumorogenicity shown for metronidazole in mouse and rat studies, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the concentration similar to those found in plasma.
Use in Children: Safety and effectiveness in children have not been established except for the treatment of amoebiasis.
Oral suspension: Mutagenicity studies: Although metronidazole has shown mutagenic activity in a number of in vitro assay systems. Studies in mammals (in vivo) have failed to demonstrate a potential for genetic damage.

FC tablet: Use in Pregnancy: Metronidazole crosses the placental barrier and enters the fetal circulation rapidly. Reproduction studies have been performed in rats at doses up to five times the human close and have revealed no evidence of impaired fertility or harm to the fetus due to Metronidazole.
Use in Lactation: Because of the potential for tumorogenicity shown for metronidazole in mouse and rat studies, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the concentration similar to those found in plasma.

The following reactions have also been reported during treatment with Metrogyl (Metronidazole): Mouth: A sharp unpleasant metallic taste is not unusual.
Oral suspension: Furry tongue, glossing and stomatitis have occurred; these may be associated with a sudden overgrowth of Candida which may occur during effective therapy.
Hematopoietic: Reversible neutropenia (leukopenia), rarely, reversible thrombocytopenia.
Cardiovascular: Flattening of the T-wave may be seen in electrocardiographic tracings.
Central Nervous System: Convulsive seizures, peripheral neuropathy, dizziness, vertigo, in-coordination, ataxia, confusion, irritability, depression, weakness, and insomnia.
Hypersensitivity: Urticaria, erythematous rash, flushing, nasal congestion, dryness of the mouth (or vagina or vulva) and fever.
Renal: Dysuria, cystitis, polyuria, incontinence, and a sense of pelvic pressure.
Oral suspension: Instances of darkened urine have been reported and seen to have no clinical significance.

FC tablet: Metronidazole has been reported to potentiate the anticoagulant effect of warfarin and other oral coumarin anticoagulants, resulting in a prolongation of prothrombin time. This possible drug interaction should be considered when metronidazole is prescribed for patients on this type of anticoagulant, therapy. The simultaneous administration of drugs that induce micorsomal liver enzymes, such as phenytoin or Phenobarbital, may accelerate the elimination of metronidazole, resulting in reduced plasma levels; impaired clearance of pheytoin has also been reported. The simultaneous administration of drugs that decrease microsomal liver enzyme activity, such as cimetidine, may prolong the half-life and decrease plasma clearance of metronidazole. In patients stabilized on relatively high doses of serum lithium, short-term cases, signs of lithium toxicity. Serum lithium and serum creatinine levels should be precede clinical symptoms of lithium intoxication. Alcoholic beverages should not be consumed during Metronidazole therapy and for at least one day afterward because abdominal cramps, nausea, vomiting, headaches, and flushing may occur. Psychotic reactions have been reported in alcoholic patients who are using metronidazole and disulfiram concurrently. Metronidazole should not be given to patients who have taken disulfiram within the last two weeks.

Store below 30°C in a cool, dry place. Protect from light.
Shelf-Life: FC tablet: 5 years.
Oral suspension: 36 months from the date of manufacture.

Antiamoebics

P01AB01 - metronidazole ; Belongs to the class of nitroimidazole derivatives antiprotozoals. Used in the treatment amoebiasis and other protozoal diseases.

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