Generic Name: salicylic acid
Dosage Form: shampoo
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(salicylic acid) 6% w/applicator
FOR TOPICAL USE ONLY. NOT FOR OPHTHALMIC, ORAL OR INTRAVAGINAL USE.
DESCRIPTION: KERALYT® shampoo contains 6% w/w salicylic acid USP in a vehicle composed of purified water, ammonium lauryl sulfosuccinate, cocamidopropyl betaine, hexylene glycol, linoleamidopropyl PG-dimonium chloride phosphate, polyquaternium-22, propylene glycol, sodium C14-16 olefin sulfonate, sodium citrate, sodium lauroyl sarcosinate, tetrasodium EDTA, tocopherol acetate and fragrance.
Salicylic acid is the 2 hydroxy derivative of benzoic acid having the following structure:
CLINICAL PHARMACOLOGY: Salicylic acid has been shown to produce desquamation of the horny layer of skin while not affecting qualitative or quantitative changes in structure of the viable epidermis.¹, ² The mechanism of action has been attributed to a dissolution of intercellular cement substance.³ In a study of the percutaneous absorption of salicylic acid in four patients with extensive active psoriasis, Taylor and Halprin⁴ showed that 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.⁵ (See PRECAUTIONS).
The major metabolites identified in the urine after topical administration are salicyluric acid (52%), salicylate glucuronides (42%), and free salicylic acid (6%).⁴ The urinary metabolites after percutaneous absorption differ from those after oral salicylate administration; those derived from percutaneous absorption contain more 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.⁵
Fifty to eighty percent of salicylate is protein bound to albumin. Salicylates compete with the binding of several drugs and can modify the action of these drugs. By similar competitive mechanisms other drugs can influence the serum levels of salicylate.⁵ (See PRECAUTIONS).
INDICATIONS AND USAGE - For the removal of excess keratin in hyperkeratotic disorders, including scaling associated with scalp psoriasis or thickened skin of palms and soles, corns and calluses.
CONTRAINDICATIONS: Keralyt Shampoo should not be used in any patient known to be sensitive to salicylic acid or any other listed ingredient. Keralyt Shampoo should not be used in children under 2 years of age.
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 under 12 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, hyperpnoea, diarrhea, psychic disturbances. In the event of salicylic acid toxicity, the use of Keralyt Shampoo should be discontinued. Fluids should be administered to promote urinary excretion. Treat- ment with sodium bicarbonate (oral or intravenous) should be instituted as appropriate.
Considering the potential risk of developing Reye’s Syndrome, salicylate products should not be administered to children or teenagers with varicella or influenza, unless directed by a physician.
PRECAUTIONS: For external use only. Avoid contact with eyes and other mucous membranes. Mild burning or stinging may occur. Peeling of the skin may increase as the salicylic acid works to loosen excess keratin. If excessive burning, stinging or peeling occurs, discontinue use and consult your physician. Keep this and all medications out of reach of children.
Drug Interactions. (The following interactions are from a published review⁵ and include reports concerning both oral and topical salicylate administration. The relationship of these interactions to the use of Keralyt Shampoo 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||Decreases tubular reabsorption; clinical toxicity from methotrexate can result|
|Oral Anticoagulant||Increased bleeding|
II. Drugs changing salicylate levels by altering renal tubular reabsorption:
|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:
|Heparin||Salicylate decreases platelet adhesiveness 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 therapy⁶:
|Laboratory Tests||Effect of Salicylates|
|Thyroid Function||Decreased PBI; increased T3 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 FeCl3 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|
Pregnancy (Category C): Salicylic acid has been shown to be teratogenic in rats and monkeys. It is difficult to extrapolate from oral doses of acetyl salicylic acid used in these studies to topical administration as the oral dose to monkeys may represent 4 times the maximum daily human dose of salicylic acid (as supplied in one bottle, 8 oz. of Keralyt Shampoo) when applied topically over a large body surface. There are no adequate and well-controlled studies in pregnant women. Keralyt Shampoo should be used during pregnancy only if the potential benefit justifies the risk to the fetus.
Nursing Mothers: Because of the potential for serious adverse reactions in nursing infants from the mother’s use of Keralyt Shampoo, 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. If used by nursing mothers, it should not be in the chest area in order to avoid accidental exposure to a nursing child.
ADVERSE REACTIONS: Excessive erythema and scaling conceivably could result from use on open skin lesions.
OVERDOSAGE - See WARNINGS
DOSAGE AND ADMINISTRATION
For use as a concentrated scalp treatment BEFORE bathing: Do not wet hair. Twist open applicator tip and apply Keralyt Shampoo w/applicator evenly, directly to affected areas of the scalp. Leave on for 5 minutes, gradually increasing treatment time up to one hour, or as directed by physician. Wash hands after applying Keralyt Shampoo w/applicator. After treatment, rinse thoroughly with water. Although no additional shampoo is needed to cleanse hair, a non-medicated shampoo may be used if desired. For use as a medicated shampoo: Wet hair and apply Keralyt Shampoo w/applicator to the scalp. Work into a lather, leave on for several minutes, then rinse. Use daily until the condition clears. After clearing is apparent, use Keralyt Shampoo w/applicator occasionally to maintain clearing or as directed by your physician.
HOW SUPPLIED: 160 mL plastic bottles NDC 11086-043-06
Store at controlled room temperature 59° to 86° F (15° to 30° C)
1. Davies M, Marks R: Br J Dermatol 95: 187-192,1976.
2. Marks R, Davies M, Cattel A: J Invest Dermatol 64: 283, 1975.
3. Huber C, Christophers E: Arch Derm Res 257: 293-297, 1977.
4. Taylor JR, Halprin KM: Arch Dermatol 111: 740-743, 1975.
5. Goldsmith LA: Int J Dermatol 18: 32-36.
6. Wilson JG, Ritter EJ, Scott WJ, Fradlein R: Tox Appl Pharmacol 41: 67-78, 1977.
EMS Contract Packaging, Hatfield, PA 19440
Summers Laboratories, Inc. Collegeville, PA 19426
1-800-533-SKIN (7546) • www.sumlab.com
KERALYT is a trademark of Summers Laboratories, Inc.
salicylic acid shampoo
|Labeler - Summers Laboratories Inc (002382612)|