Metrogyl

Metronidazole.

Each gram of gel contains: Metronidazole USP 10 mg (1% w/w).

Pharmacology: Pharmacokinetics: Topical administration of a one gram dose of Metronidazole (Metrogyl), to the face of 13 patients with moderate to severe rosacea once daily for 7 days resulted in a mean ± SD C_max of metronidazole of 32 ± 9 ng/mL. The mean SD AUC_(0-24) was 595 ± 154 ng*hr/mL. The mean C_max and AUC_(0-24) are less than 1% of the value reported for a single 250 mg oral dose of metronidazole. The time to maximum plasma concentration (T_max) was 6-10 hours after topical application.

Metronidazole (Metrogyl) is indicated for tropical application in the treatment of inflammatory papules, pustules and erythema of rosacea and acne vulgaris. It is also indicated in the treatment of any cutaneous ulceration, foot ulcers associated with diabetes mellitus, varicose veins, leprosy, arterial insufficiency and for episiotomy wounds.

Apply and rub a thin film of gel twice daily, morning and evening to entire affected areas after washing. Significant therapeutic results should be noticed within three weeks. Clinical studies have demonstrated continuing improvement through nine weeks of therapy. Areas to be treated should be cleaned before application of Metronidazole (Metrogyl). Patients may use cosmetics after application of Metronidazole (Metrogyl). In acne vulgaris, oral antibiotic therapy should be continued.
Or as prescribed by the physician.

There is no human experience with overdosage of metronidazole.

Metronidazole (Metrogyl), is contraindicated in those patients with a history of hypersensitivity to metronidazole or to any other ingredient in this formulation.

General: Topical Metronidazole (Metrogyl) has been reported to cause tearing of the eyes. Therefore, contact with the eyes should be avoided. If a reaction suggesting local skin irritation occurs, patients should be directed to use the medication less often or discontinue use. Metronidazole is a nitroimidazole and should be used with care in patients with evidence of, or history of, blood dyscrasia.
Carcinogenicity and Mutagenicity: Metronidazole (Metrogyl) is mutagenic in bacterial assays, and its hydroxy metabolite even more so, but studies of mammalian cells in vitro and in vivo have not consistently demonstrated a mutagenic effect. Similarly, there is no uniformity in the limited data concerning genotoxicity in humans, and although Metronidazole (Metrogyl) has been classified as carcinogen in animals, the evidence of human carcinogenicity is ambiguous. There was no appreciable increase in the incidence of cancer in a retrospective study of 771 patients given Metronidazole (Metrogyl) for vaginal trichomoniasis, nor in another similar study of 2460 patients. The first study did show an excess of cases of lung cancer, although all 4 were in women who were smokers. Subsequent follow-up to 1984, covering a period of 15 to 25 years, still showed an excess of lung cancer cases even after allowing for smoking status. However, this follow-up also continued to show no significant increase overall in cancer-related morbidity or mortality. Follow-up of the patients from the second study for 11 to 15 years to 1984 also showed no increase in the overall incidence of cancers nor did it confirm any increase in lung cancer.
Use in Children: Safety and effectiveness in pediatric patients have not been established.
Use in the Elderly: While specific clinical trials in the geriatric population have not been conducted, sixty-six patients aged 65 years and older treated with Metronidazole over ten weeks showed comparable safety and efficacy as compared to the general study population.

Pregnancy: Teratogenic Effects: Pregnancy Category B. There are no adequate and well-controlled studies with the use of Metronidazole gel 1% in pregnant women. Metronidazole crosses the placental barrier and enters the fetal circulation rapidly. No fetotoxicity was observed after oral administration of metronidazole in rats or mice at 200 and 20 times, respectively, the expected clinical dose. However, oral metronidazole has shown carcinogenic activity in rodents. Because animal reproduction studies are not always predictive of human response, Metronidazole (Metrogyl) should be used during pregnancy only if clearly needed.
Nursing Mothers: After oral administration, metronidazole is secreted in breast milk in concentrations similar to those found in the plasma. Even though blood levels taken after topical metronidazole application are significantly lower than those achieved after oral metronidazole, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother and the risk to the infant.

The adverse effects of metronidazole are generally dose-related. The most common are gastrointestinal disturbances, especially nausea and an unpleasant metallic taste. Vomiting, and diarrhoea or constipation may also occur. A furred tongue, glossitis, and stomatitis may be associated with an overgrowth of Candida. There have been rare reports of antibiotic-associated colitis associated with metronidazole, although it is also used in the treatment of this condition. Weakness, dizziness, ataxia, headache, drowsiness, insomnia, and changes in mood or mental state such as depression or confusion have also been reported. Peripheral neuropathy, usually presenting as numbness or tingling in the extremities, and epileptic seizures has been associated with high doses of metronidazole or prolonged treatment. Temporary moderate leucopenia and thrombocytopenia may occur in some patients receiving metronidazole. Skin rashes, urticaria, and pruritus occur occasionally and erythema multiform, angioedema, and anaphylaxis have been reported rarely.
Other adverse effects include urethral discomfort and darkening of the urine. Raised liver enzyme values, cholestatic hepatitis, and jaundice have occasionally been reported. Thrombophlebitis may follow intravenous use of metronidazole.

Oral metronidazole has been reported to potentiate the anticoagulant effect of coumarin and warfarin resulting in a prolongation of prothrombin time. Drug interactions should be kept in mind when Metronidazole (Metrogyl), 1% is prescribed for patients who are receiving anticoagulant treatment, although they are less likely to occur with topical metronidazole administration because of low absorption.

Information for Patients: Patients using Metronidazole (Metrogyl), should receive the following information and instructions: This medication is to be used as directed.
2. It is for external use only.
3. Avoid contact with the eyes.
4. Cleanse affected area(s) before applying Metronidazole (Metrogyl).
5. This medication should not be used for any other condition than that for which it is prescribed.
6. Patients should report any adverse effects to their physicians.

Store at temperatures not exceeding 25°C.

Topical Antibiotics

D06BX01 - metronidazole ; Belongs to the class of other topical chemotherapeutics used in the treatment of dermatological diseases.

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