TRETINOIN

Tretinoin Gel Microsphere, 0.1%, 0.08% and 0.04% is a white to very pale yellow opaque gel for topical treatment of acne vulgaris. Chemically, tretinoin is all-trans-retinoic acid, also known as (all-E)-3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nonatetraenoic acid. It is a member of the retinoid class of compounds and a metabolite of naturally occurring Vitamin A. Tretinoin has a molecular weight of 300.44, a molecular formula of C 20 H 28 O 2 and the following chemical structure: Each gram of Tretinoin Gel Microsphere, 0.1%, contains 1 mg of tretinoin. Each gram of Tretinoin Gel Microsphere, 0.08%, contains 0.8 mg of tretinoin. Each gram of Tretinoin Gel Microsphere, 0.04%, contains 0.4 mg of tretinoin. The formulation contains methyl methacrylate/glycol dimethacrylate crosspolymer (MICROSPONGE ® System), propylene glycol dicaprylate/dicaprate and butylated hydroxytoluene to enable inclusion of the active ingredient, tretinoin, in an aqueous gel. Other components consist of benzyl alcohol, butylated hydroxytoluene, carbomer 974P, cyclomethicone and dimethicone copolyol, disodium EDTA, glycerin, PPG-20 methyl glucose ether distearate, propylene glycol, purified water, sorbic acid, and trolamine. chemstructure.jpg

Tretinoin Gel Microsphere is a retinoid indicated for topical application in the treatment of acne vulgaris. Tretinoin Gel Microsphere, 0.1%, 0.08% and 0.04%, is a retinoid, indicated for topical treatment of acne vulgaris. ( 1 )

For topical use only. Not for ophthalmic, oral, or intravaginal use. Tretinoin Gel Microsphere should be applied once a day, in the evening, to the skin where acne lesions appear, using enough to cover the entire affected area in a thin layer. Areas to be treated should be cleansed thoroughly before the medication is applied. If medication is applied excessively, no more rapid or better results will be obtained and marked redness, peeling, or discomfort may occur. A transitory feeling of warmth or slight stinging may be noted on application. In cases where it has been necessary to temporarily discontinue therapy or to reduce the frequency of application, therapy may be resumed or the frequency of application increased as the patient becomes able to tolerate the treatment. Frequency of application should be closely monitored by careful observation of the clinical therapeutic response and skin tolerance. Efficacy has not been established for less than once daily dosing frequencies. During the early weeks of therapy, an apparent exacerbation of inflammatory lesions may occur. If tolerated, this should not be considered a reason to discontinue therapy [see Adverse Reactions (6.1) ] . Therapeutic results may be noticed after two weeks, but more than seven weeks of therapy are required before consistent beneficial effects are observed. Tretinoin Gel Microsphere should be kept away from the eyes, the mouth, paranasal creases of the nose, and mucous membranes. Patients treated with Tretinoin Gel Microsphere may use cosmetics. Concomitant topical medication, medicated or abrasive soaps and cleansers, products that have a strong drying effect, products with high concentrations of alcohol, astringents, or spices should be used with caution because of possible interaction with tretinoin. Avoid contact with the peel of limes. Particular caution should be exercised with the concomitant use of topical over-the-counter acne preparations containing benzoyl peroxide, sulfur, resorcinol, or salicylic acid with Tretinoin Gel Microsphere. It also is advisable to allow the effects of such preparations to subside before use of Tretinoin Gel Microsphere is begun. • Apply a thin layer of Tretinoin Gel Microsphere once daily, before bedtime, to skin where lesions occur. Keep away from eyes, mouth, nasal creases, and mucous membranes. (2 ) • Not for oral, ophthalmic, or intravaginal use. ( 2 )

None. None. (4 )

Most common adverse reactions are skin pain, pruritus, skin irritation/subcutaneous irritation, pharyngitis, and erythema. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Oceanside Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Clinical Trials in Subjects with Acne In separate clinical trials for each concentration, acne subjects treated with Tretinoin Gel Microsphere, 0.1% or 0.04%, over the twelve-week period showed that cutaneous irritation scores for erythema, peeling, dryness, burning/stinging, or itching peaked during the initial two weeks of therapy, decreasing thereafter. Approximately half of the subjects treated with Tretinoin Gel Microsphere, 0.04%, had cutaneous irritation at Week 2. Of those subjects who did experience cutaneous side effects, most had signs or symptoms that were mild in severity (severity was ranked on a 4-point ordinal scale: 0=none, 1=mild, 2=moderate, and 3=severe). Less than 10% of patients experienced moderate cutaneous irritation and there was no severe irritation at Week 2. In trials of Tretinoin Gel Microsphere, 0.04%, throughout the treatment period the majority of subjects experienced some degree of irritation (mild, moderate, or severe) with 1% (2/225) of subjects having scores indicative of a severe irritation; 1.3% (3/225) of subjects treated with Tretinoin Gel Microsphere, 0.04%, discontinued treatment due to irritation, which included dryness in one patient and peeling and urticaria in another. In trials of Tretinoin Gel Microsphere, 0.1%, no more than 3% of subjects had cutaneous irritation scores indicative of severe irritation; 6% (14/224) of subjects treated with Tretinoin Gel Microsphere, 0.1%, discontinued treatment due to irritation. Of these 14 subjects, four had severe irritation after 3 to 5 days of treatment, with blistering in one subject. In a double-blind trial with 156 acne subjects comparing 12 weeks of treatment with Tretinoin Gel Microsphere, 0.04% or 0.1%, (78 subjects each group), the most frequently-reported adverse events affected the skin and subcutaneous tissue (15.4% in the 0.04% group, and 20.5% in the 0.1% group). The most prevalent of the dermatologic adverse events in the 0.04% group was skin irritation (6.4%); and in the 0.1% group skin burning (7.7%), erythema (5.1%), skin irritation (3.8%), and dermatitis (3.8%). Most adverse events were of mild intensity (63.4%), and 34.4% were moderate. One subject in each group had adverse events characterized as severe, neither were dermatologic findings and neither was characterized as related to drug by the investigator. Trials in Subjects without Acne In a half-face comparison trial conducted for up to 14 days in women with sensitive skin, but without acne, Tretinoin Gel Microsphere, 0.1%, was statistically less irritating than tretinoin cream, 0.1%. In addition, a cumulative 21-day irritation evaluation in subjects with normal skin showed that Tretinoin Gel Microsphere, 0.1%, had a lower irritation profile than tretinoin cream, 0.1%. The clinical significance of these irritation studies for patients with acne is not established. Comparable effectiveness of Tretinoin Gel Microsphere, 0.1%, and tretinoin cream, 0.1%, has not been established. The lower irritancy of Tretinoin Gel Microsphere, 0.1%, in subjects without acne may be attributable to the properties of its vehicle. The contribution of decreased irritancy by the MICROSPONGE ® System has not been established. No irritation trials have been performed to compare Tretinoin Gel Microsphere, 0.04%, with either Tretinoin Gel Microsphere, 0.1%, or tretinoin cream, 0.1%. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of Tretinoin Gel Microsphere. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Temporary hyper- or hypopigmentation has been reported with repeated application of tretinoin.