Salicylic Acid

INDICATIONS AND USAGE For Dermatologic Use: Salicylic Acid 6% Gel is a topical aid in the removal of excessive keratin in hyperkeratotic skin disorders including verrucae, and the various ichthyoses (vulgaris, sex-linked and lamellar), keratosis palmaris and plantaris, keratosis pilaris, pityriasis rubra pilaris, and psoriasis (including body, scalp, palms and soles). For Podiatric Use: Salicylic Acid 6% Gel is a topical aid in the removal of excessive keratin on dorsal and plantar hyperkeratotic lesions.

DOSAGE AND ADMINISTRATION - The preferable method of use is to apply KERALYT GEL thoroughly to the affected area and occlude the area at night. Preferably, the skin should be hydrated for at least five minutes prior to application. The medication is washed off in the morning and if excessive drying and/or irritation is observed a bland cream or lotion may be applied. Once clearing is apparent, the occasional use of KERALYT GEL will usually maintain the remission. In those areas where occlusion is difficult or impossible, application may be made more frequently; hydration by wet packs or baths prior to application apparently enhances the effect. Unless hands are being treated, hands should be rinsed thoroughly after application. For use as a scalp treatment: KERALYT GEL should be applied directly to the affected areas of the scalp on a frequency directed by your physician. The applicator tip will provide accurate application, avoiding contact with normal hair or skin. The gel should be washed off after 10 to 20 minutes initially, but it can be left on for up to an hour as treatment progresses. The gel can be washed off using KERALYT SHAMPOO or warm water in a bath or shower.

WARNINGS Prolonged use over large areas, especially in children and those patients with significant renal or hepatic impairment, could result in salicylism. Concomitant use of other drugs which may contribute to elevated serum salicylate levels should be avoided where the potential for toxicity is present. In children under12 years of age and those patients with renal or hepatic impairment, the area to be treated should be limited and the patient monitored closely for signs of salicylate toxicity: nausea, vomiting, dizziness, loss of hearing, tinnitus, lethargy, hyperpnea, diarrhea, and psychic disturbances. In the event of salicylic acid toxicity, the use of Salicylic Acid 6% Gel should be discontinued. Fluids should be administered to promote urinary excretion. Treatment with sodium bicarbonate (oral or intravenous) should be instituted as appropriate. Patients should be cautioned against the use of oral aspirin and other salicylate containing medications, such as sports injury creams, to avoid additional excessive exposure to salicylic acid. When needed, aspirin should be replaced by an alternative non-steroidal anti-inflammatory agent that is not salicylate based. Patients should be advised not to apply occlusive dressings, clothing or other occlusive topical products such as petrolatum-based ointments to prevent excessive systemic exposure to salicylic acid. Excessive application of the product other than what is needed to cover the affected area will not result in a more rapid therapeutic benefit. Due to potential risk of developing Reye's syndrome, salicylate products should not be used in children and teenagers with varicella or influenza, unless directed by a licensed health care practitioner.

CONTRAINDICATIONS: This product is contraindicated in persons with known or suspected hypersensitivity to any of the ingredients of the product. Patients with diabetes or impaired blood circulation should not use this product. This product also should not be used on moles, birthmarks, and unusual warts with hair growing from them, or warts on the face.

Drug Interactions. (The following interactions are from a published review 5 and include reports concerning both oral and topical salicylate administration. The relationship of these interactions to the use of Salicylic Acid 6% Gel is not known.) I. Due to the competition of salicylate with other drugs for binding to serum albumin the following drug interactions may occur: Drug Description of Interaction Tolbutamide; Sulfonylureas Hypoglycemia potentiated Methotrexate Decrease tubular reabsorption; clinical toxicity from methotrexate can result Oral Anticoagulants Increased bleeding II. Drugs changing salicylate levels by altering renal tubular reabsorption: Drug Description of Interaction Corticosteroids Decreases plasma salicylate level; tapering doses of steroids may promote salicylism Ammonium Sulfate Increases plasma salicylate level III. Drugs with complicated interactions with salicylates: Drug Description of Interaction Heparin Salicylate decreases platelet adhesivesness and interferes with hemostasis in heparin-treated patients Pyrazinamide Inhibits pyrazinamide-induced hyperuricemia Uricosuric Agents Effect of probenecid, sulfinpyrazone and phenylbutazone inhibited The following alterations of laboratory tests have been reported during salicylate therapy 6 : Laboratory Tests Effect of Salicylates Thyroid Function Decreased PBI; increased T 3 uptake Urinary Sugar False negative with glucose oxidase; false positive with Clinitest with high-dose salicylate therapy (2 - 5 g qd) 5 Hydroxyindole Acetic Acid False negative with fluorometric test Acetone, Ketone Bodies False positive FeCl 3 in Gerhardt reaction; red color persists with boiling 17-OH Corticosteroids False reduced values with >4.8 g qd salicylate Vanilmandelic Acid False reduced values Uric Acid May increase or decrease depending on dose Prothrombin Decreased levels; slightly increased prothrombin time

ADVERSE REACTIONS: Localized irritation may occur if this product is applied to normal skin surrounding the wart; however irritation may normally be controlled by temporarily discontinuing use and by applying the medication only to the wart site when treatment is resumed. To report a serious adverse event, call 1-855-899-4237.

CLINICAL PHARMACOLOGY Salicylic acid has been shown to produce desquamation of the horny layer of skin while not affecting qualitative or quantitative changes in the structure of the viable epidermis. The mechanism of action has been attributed to the dissolution of intercellular cement substances. In a study of the percutaneous absorption of salicylic acid in a 6% salicylic acid gel in four patients with extensive active psoriasis, Taylor and Halprin showed that the peak serum salicylate levels never exceeded 5 mg/100 ml even though more than 60% of the applied salicylic acid was absorbed. Systemic toxic reactions are usually associated with much higher serum levels (30 to 40 mg/100 ml). Peak serum levels occurred within 5 hours of the topical application under occlusion. The sites were occluded for 10 hours over the entire body surface below the neck. Since salicylates are distributed in the extracellular space, patients with a contracted extracellular space due to dehydration or diuretics have higher salicylate levels than those with a normal extracellular space (See PRECAUTIONS ). The major metabolites identified in the urine after topical administration are salicylic acid (52%), salicylate glucuronides (42%) and free salicylic acid (6%). The urinary metabolites after percutaneous absorption differ from those after oral salicylate administration; those derived from percutaneous absorption contain more salicylate glucuronides and less salicyluric and salicylic acid. Almost 95% of a single dose of salicylate is excreted within 24 hours of its entrance into the extracellular space. Fifty to eighty percent of salicylate is protein bound to albumin. Salicylates compete with the binding of several drugs and can modify the actions of these drugs. By similar competitive mechanisms other drugs can influence the serum levels of salicylate (See PRECAUTIONS ).