Clindamycin Phosphate and Tretinoin

1 INDICATIONS AND USAGE Clindamycin phosphate and tretinoin gel is indicated for the topical treatment of acne vulgaris in patients 12 years and older. Clindamycin phosphate and tretinoin gel is a lincosamide antibiotic and retinoid combination product indicated for the topical treatment of acne vulgaris in patients 12 years and older. ( 1 )

2 DOSAGE AND ADMINISTRATION Clindamycin phosphate and tretinoin gel should be applied once daily in the evening, gently rubbing the medication to lightly cover the entire affected area. Approximately a pea-sized amount will be needed for each application. Avoid the eyes, lips, and mucous membranes. Clindamycin phosphate and tretinoin gel is not for oral, ophthalmic, or intravaginal use. Apply a pea-sized amount once daily in the evening lightly covering the entire affected area. Avoid the eyes, lips, and mucous membranes. ( 2 ) Not for oral, ophthalmic, or intravaginal use. ( 2 )

4 CONTRAINDICATIONS Clindamycin phosphate and tretinoin gel is contraindicated in patients with regional enteritis, ulcerative colitis, or history of antibiotic-associated colitis. Clindamycin phosphate and tretinoin gel is contraindicated in patients with regional enteritis, ulcerative colitis, or history of antibiotic-associated colitis. ( 4 )

5 WARNINGS AND PRECAUTIONS Colitis: Clindamycin can cause severe colitis, which may result in death. Diarrhea, bloody diarrhea, and colitis (including pseudomembranous colitis) have been reported with the use of clindamycin. Clindamycin phosphate and tretinoin gel should be discontinued if significant diarrhea occurs. ( 5.1 ) Ultraviolet Light and Environmental Exposure: Avoid exposure to sunlight, sunlamps, and weather extremes. Wear sunscreen daily. ( 5.2 ) 5.1 Colitis Systemic absorption of clindamycin has been demonstrated following topical use. Diarrhea, bloody diarrhea, and colitis (including pseudomembranous colitis) have been reported with the use of topical clindamycin. If significant diarrhea occurs, clindamycin phosphate and tretinoin gel should be discontinued. Severe colitis has occurred following oral or parenteral administration of clindamycin with an onset of up to several weeks following cessation of therapy. Antiperistaltic agents such as opiates and diphenoxylate with atropine may prolong and/or worsen severe colitis. Severe colitis may result in death. Studies indicate a toxin(s) produced by clostridia is one primary cause of antibiotic-associated colitis. The colitis is usually characterized by severe persistent diarrhea and severe abdominal cramps and may be associated with the passage of blood and mucus. Stool cultures for Clostridium difficile and stool assay for C. difficile toxin may be helpful diagnostically. 5.2 Ultraviolet Light and Environmental Exposure Exposure to sunlight, including sunlamps, should be avoided during the use of clindamycin phosphate and tretinoin gel. Patients with sunburn should be advised not to use the product until fully recovered because of heightened susceptibility to sunlight as a result of the use of tretinoin. Patients who may be required to have considerable sun exposure due to occupation and those with inherent sensitivity to the sun should exercise particular caution. Daily use of sunscreen products and protective apparel (e.g., a hat) are recommended. Weather extremes, such as wind or cold, also may be irritating to patients under treatment with clindamycin phosphate and tretinoin gel.

7 DRUG INTERACTIONS Clindamycin phosphate and tretinoin gel should not be used in combination with erythromycin-containing products because of its clindamycin component. ( 7.1 ) 7.1 Erythromycin Clindamycin phosphate and tretinoin gel should not be used in combination with erythromycin-containing products due to possible antagonism to the clindamycin component. In vitro studies have shown antagonism between these 2 antimicrobials. The clinical significance of this in vitro antagonism is not known. 7.2 Neuromuscular Blocking Agents Clindamycin has been shown to have neuromuscular blocking properties that may enhance the action of other neuromuscular blocking agents. Therefore, clindamycin phosphate and tretinoin gel should be used with caution in patients receiving such agents.

6 ADVERSE REACTIONS Observed local treatment-related adverse reactions (≥ 1%) in clinical studies with clindamycin phosphate and tretinoin gel were application site reactions, including dryness, irritation, exfoliation, erythema, pruritus, and dermatitis. Sunburn was also reported. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Solaris Pharma Corporation at 1-833-919-0527 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Adverse Reactions in Clinical Studies Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in clinical practice. The safety data reflect exposure to clindamycin phosphate and tretinoin gel in 1,104 patients with acne vulgaris. Patients were 12 years or older and were treated once daily in the evening for 12 weeks. Adverse reactions that were reported in ≥1% of patients treated with clindamycin phosphate and tretinoin gel are presented in Table 1 . Table 1: Treatment-Related Adverse Reactions Reported by ≥1% of Patients Clindamycin Phosphate and Tretinoin Gel N = 1,104 n (%) Clindamycin Gel N = 1,091 n (%) Tretinoin Gel N = 1,084 n (%) Vehicle Gel N = 552 n (%) Patients with at least one adverse reaction 140 (13) 38 (3) 141 (13) 17 (3) Application site dryness 64 (6) 12 (1) 62 (6) 3 (1) Application site irritation 50 (5) 4 (<1) 57 (5) 5 (1) Application site exfoliation 50 (5) 2 (<1) 56 (5) 2 (<1) Application site erythema 40 (4) 6 (1) 39 (4) 3 (1) Application site pruritus 26 (2) 7 (1) 23 (2) 6 (1) Sunburn 11 (1) 6 (1) 7 (1) 3 (1) Application site dermatitis 6 (1) 0 (0) 8 (1) 1 (<1) Local skin reactions actively assessed at baseline and end of treatment with a score >0 are presented in Table 2 . Table 2: Clindamycin Phosphate and Tretinoin Gel - Treated Patients with Local Skin Reactions Clindamycin Phosphate and Tretinoin Gel Vehicle Gel Local Reaction Baseline N = 476 (%) End of Treatment N = 409 (%) Baseline N = 219 (%) End of Treatment N = 209 (%) Erythema 24% 21% 31% 35% Scaling 8% 19% 14% 12% Dryness 11% 22% 18% 13% Burning 8% 13% 8% 4% Itching 17% 15% 22% 14% During the 12 weeks of treatment, each local skin reaction peaked at Week 2 and gradually reduced thereafter.

8.1 Pregnancy Pregnancy Category C. There are no well-controlled studies in pregnant women treated with clindamycin phosphate and tretinoin gel. Clindamycin phosphate and tretinoin gel should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. A limit teratology study performed in Sprague Dawley rats treated topically with clindamycin phosphate and tretinoin gel or 0.025% tretinoin gel at a dose of 2 mL/kg during gestation days 6 to 15 did not result in teratogenic effects. Although no systemic levels of tretinoin were detected, craniofacial and heart abnormalities were described in drug-treated groups. These abnormalities are consistent with retinoid effects and occurred at 16 times the recommended clinical dose assuming 100% absorption and based on body surface area comparison. For purposes of comparison of the animal exposure to human exposure, the recommended clinical dose is defined as 1 g of clindamycin phosphate and tretinoin gel applied daily to a 50-kg person. Clindamycin: Reproductive developmental toxicity studies performed in rats and mice using oral doses of clindamycin up to 600 mg/kg/day (480 and 240 times the recommended clinical dose based on body surface area comparison, respectively) or subcutaneous doses of clindamycin up to 180 mg/kg/day (140 and 70 times the recommended clinical dose based on body surface area comparison, respectively) revealed no evidence of teratogenicity. Tretinoin: Oral tretinoin has been shown to be teratogenic in mice, rats, hamsters, rabbits, and primates. It was teratogenic and fetotoxic in Wistar rats when given orally at doses greater than 1 mg/kg/day (32 times the recommended clinical dose based on body surface area comparison). However, variations in teratogenic doses among various strains of rats have been reported. In the cynomologous monkey, a species in which tretinoin metabolism is closer to humans than in other species examined, fetal malformations were reported at oral doses of 10 mg/kg/day or greater, but none were observed at 5 mg/kg/day (324 times the recommended clinical dose based on body surface area comparison), although increased skeletal variations were observed at all doses. Dose-related teratogenic effects and increased abortion rates were reported in pigtail macaques. With widespread use of any drug, a small number of birth defect reports associated temporally with the administration of the drug would be expected by chance alone. Thirty cases of temporally associated congenital malformations have been reported during 2 decades of clinical use of another formulation of topical tretinoin. Although no definite pattern of teratogenicity and no causal association have been established from these cases, 5 of the reports describe the rare birth defect category, holoprosencephaly (defects associated with incomplete midline development of the forebrain). The significance of these spontaneous reports in terms of risk to fetus is not known.