METRONIDAZOLE

Metronidazole Topical Lotion, 0.75% contains metronidazole, USP, at a concentration of 7.5 mg per gram (0.75% w/w) in a lotion consisting of benzyl alcohol, carbomer 941, cyclomethicone, glycerin, glyceryl stearate, light mineral oil, PEG-100 stearate, polyethylene glycol 400, potassium sorbate, purified water, steareth-21, stearyl alcohol, and sodium hydroxide and/or lactic acid to adjust pH. Metronidazole is an imidazole and is classified therapeutically as an antiprotozoal and antibacterial agent. Chemically, metronidazole is 2-methyl-5-nitro-1 H -imidazole-1-ethanol. The molecular formula is C 6 H 9 N 3 O 3 and molecular weight is 171.16. Metronidazole is represented by the following structural formula: Structural Formula

Metronidazole topical lotion is indicated for topical application in the treatment of inflammatory papules and pustules of rosacea. CLINICAL STUDIES A controlled clinical study was conducted in 144 patients with moderate to severe rosacea, in which metronidazole topical lotion was compared with its vehicle. Applications were made twice daily for 12 weeks during which patients were instructed to avoid spicy foods, thermally hot foods and drinks, alcoholic beverages, and caffeine. Patients were also provided samples of a soapless cleansing lotion and, if requested, a moisturizer. Metronidazole topical lotion was significantly more effective than its vehicle in mean percent reduction of inflammatory lesions associated with rosacea and in the investigator's global assessment of improvement. The results of the mean percent reduction in inflammatory lesion counts from baseline after 12 weeks of treatment and the investigators' global assessment of improvement at week 12 are presented in the following table: Efficacy Outcomes at Week 12 Mean Percent Reduction in Inflammatory Lesion Counts from Baseline Metronidazole Topical Lotion N=65 Vehicle Lotion N=60 55% 20% Investigators' Global Assessment of Improvement (percent change from baseline) Worse No Change Minimal Improvement Definite Improvement Marked Improvement Clear Metronidazole Topical Lotion N=65 5% 12% 11% 32% 32% 8% Vehicle Lotion N=60 15% 27% 23% 15% 20% 0% The scale is based on the following definitions: Worse: Exacerbation of either erythema or quantitative assessment of papules and/or pustules. No Change: Condition remains the same. Minimal Improvement: Slight improvement in the quantitative assessment of papules and/or pustules, and/or slight improvement in erythema. Definite Improvement: More pronounced improvement in the quantitative assessment of papules and/or pustules, and/or more pronounced improvement in erythema. Marked Improvement: Obvious improvement in the quantitative assessment of papules and/or pustules, and/or obvious improvement in erythema. Clear: No papules or pustules and minimal residual or no erythema.

Apply a thin layer to entire affected areas after washing. Use morning and evening or as directed by physician. Avoid application close to the eyes. Patients may use cosmetics after waiting for the metronidazole topical lotion to dry (not less than 5 minutes).

Metronidazole topical lotion is contraindicated in individuals with a history of hypersensitivity to metronidazole or to other ingredients of the formulation.

In a controlled clinical trial, safety data from 141 patients who used metronidazole topical lotion (n=71), or the lotion vehicle (n=70), twice daily and experienced a local cutaneous adverse event which may or may not have been related to the treatments include: local allergic reaction, metronidazole topical lotion 2 (3%), lotion vehicle 0; contact dermatitis, metronidazole topical lotion 2 (3%), lotion vehicle 1 (1%); pruritus, metronidazole topical lotion 1 (1%), lotion vehicle 0; skin discomfort (burning and stinging), metronidazole topical lotion 1 (1%), lotion vehicle 2 (3%); erythema, metronidazole topical lotion 4 (6%), lotion vehicle 0; dry skin, metronidazole topical lotion 0, lotion vehicle 1 (1%); and worsening of rosacea, metronidazole topical lotion 1 (1%), and lotion vehicle 7 (10%). The following additional adverse experiences have been reported with the topical use of metronidazole: skin irritation, transient redness, metallic taste, tingling or numbness of extremities, and nausea.

Oral metronidazole has been reported to potentiate the anticoagulant effect of warfarin and coumarin anticoagulants, resulting in a prolongation of prothrombin time. The effect of topical metronidazole on prothrombin time is not known.