NORITATE®
Dermik Laboratories Canada
Metronidazole
Antirosacea Agent
Action And Clinical Pharmacology: Metronidazole topical cream is particularly effective against the inflammatory papulopustular component of rosacea. The mechanisms by which metronidazole act in reducing inflammatory lesions of rosacea are unknown, but may include an antibacterial and/or an anti-inflammatory effect.
Indications And Clinical Uses: For topical application in the treatment of inflammatory papules, pustules and erythema of rosacea.
Contra-Indications: In individuals with a history of hypersensitivity to metronidazole, parabens or other ingredients of the formulation.
Manufacturers’ Warnings In Clinical States: Avoid contact with eyes.
Studies in rats and mice have provided some evidence that metronidazole may cause tumors in these species when administered orally for a long period at high doses. The relevance of these findings in humans undergoing topical treatment with metronidazole is not known.
The mutagenic potential of metronidazole was tested in two ways: the dominant lethal test in mammalian germ cells, which yielded negative results, and a test using a bacterial indicator strain, which yielded positive results. The inherent antimicrobial property of metronidazole complicates the interpretation of this result with respect to any possible risk to humans.
Children: Safety and effectiveness in children have not been established.
Pregnancy: There has been no experience to date with the use of Noritate in pregnant patients. Systemically administered metronidazole crosses the placental barrier and enters the fetal circulation rapidly. No fetotoxicity was observed after oral metronidazole in rats or mice. However, because animal reproduction studies are not always predictive of the human response, this drug should be used during pregnancy only after careful assessment of the risk/benefit ratio.
Lactation: Even though metronidazole blood levels are significantly lower after topical than after oral administration, 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. After oral administration, metronidazole is secreted in breast milk in concentrations similar to those found in plasma.
Precautions: Because of the minimal absorption of metronidazole and consequently its insignificant plasma concentration after topical administration, the adverse experiences reported with the oral form of the drug have not been reported with Noritate.
General: Metronidazole has been reported to cause tearing of the eyes. Therefore, contact with the eyes should be avoided. If a reaction suggesting local irritation occurs, patients should be directed to use the medication less frequently, discontinue use temporarily or discontinue use until further instructions. Metronidazole is a nitromidazole and should be used with care in patients with evidence of, or a history of, blood dyscrasia. Although rosacea is a chronic disease, data on the long-term use of metronidazole in rosacea are not available. In controlled clinical trials, patients were treated for a maximum 2 months (see Dosage).
Drug Interactions: Drug interactions are less likely with topical administration, but should be kept in mind when metronidazole is prescribed for patients who are receiving anticoagulant treatment. Oral metronidazole has been reported to potentiate the anticoagulant effect of coumarin and warfarin resulting in a prolongation of prothrombin time. Oral metronidazole also interacts with alcohol, producing a disulfiram-like reaction. Although this response has never been reported with topically applied metronidazole, an interaction with alcohol may be a possibility.
Dermatological Sensitivity: During clinical trials, there were 3 reports of possible contact dermatitis during treatment with metronidazole. Sensitivity to metronidazole was confirmed in only 1 of these patients by re-challenging with the product. In the other patients, a clear causal relationship could not be established. Nevertheless, physicians should be aware of the possibility of skin sensitivity reactions to metronidazole and/or of cross-sensitization with other imidazole preparations, such as clotrimazole and tioconazole.
Adverse Reactions: Adverse conditions reported included transient skin irritation, dryness and stinging, as well as three cases of possible contact dermatitis. The incidence of these dermatological effects was about 3 to 4% during clinical trials.
Watering or tearing eyes may also occur if metronidazole is applied too closely to this area.
Gastrointestinal side effects (nausea, constipation, gastrointestinal upset) were reported in 7 patients (less than 2% of the total clinical experience with Noritate).
Symptoms And Treatment Of Overdose: There is no human experience with overdosage of topically applied metronidazole cream. Symptoms: Massive ingestion may produce vomiting and slight disorientation.
Treatment: There is no specific antidote. Ipecac syrup or gastric lavage; then activated charcoal followed by a saline cathartic is suggested. Treatment should include symptomatic and supportive therapy.
Dosage And Administration: Cleanse all affected areas of the skin. Then, squeeze out approximately 1/2 cm of metronidazole cream and apply to the entire affected areas twice daily, morning and evening. Rub in lightly.
Significant therapeutic results should be evident within the first month of treatment and controlled clinical studies have demonstrated continuing improvement through 8 weeks of therapy. The dosage required for long-term administration is uncertain (see Precautions).
Patients may use cosmetics after application of metronidazole.
Availability And Storage: Each g of white to slightly off-white soft cream, contains: metronidazole 10 mg (1% w/w). Nonmedicinal ingredients: glycerin, glyceryl monostearate, methylparaben, propylparaben, purified water, stearic acid and triethanolamine. Aluminum tubes of 30 g. Store at room temperature (15 to 30°C).
NORITATE® Dermik Laboratories Canada Metronidazole Antirosacea Agent
Posted by RxMed