Salicylic Acid

Salicylic Acid is an Keratolytic Agent belonging to pharmacology class of Antiacne

Salicylic Acid is Rapidly and efficiently absorbed percutaneously (65-85%). Time to peak plasma concentration: 6-12 hours and get distributed in the extracellular space. Crosses the placenta and enters breast milk. Plasma protein binding: 50-80%, to albumin and get metabolized in the liver by microsomal enzymes which get excreted mainly via urine (52% as salicyluric acid, 42% as salicylate glucuronides, 6% as salicylic acid).

The common side effects associated with Salicylic Acid include irritation, discomfort, dryness, peeling.

Salicylic Acid is available in the form of Topical liquid, gel, lotion, cream, aerosol, soap, strips, pads, disk, plaster, patch.

The molecule is available in India, USA, Japan, Germany.

Produces desquamation of hyperkeratotic epithelium via dissolution of the intercellular cement which causes the cornified tissue to swell, soften, macerate, and desquamate. Salicylic acid is used for keratolytic skin disorders at concentrations of 3% to 6%; concentrations of 5% to 40% are used to remove corns and warts; concentrations up to 2% are used for acne.

Onset of action: Treatment of warts: 1 to 2 weeks; full resolution may take >4 to 6 weeks.

Salicylic Acid is available in Topical liquid, gel, lotion, cream, aerosol, soap, strips, pads, disk, plaster, patch.

Salicylic Acid can be used in the treatment of Acne vulgaris, Dermatitis, Hyperkeratotic skin disorders.

Salicylic Acid reduces excessive cell turnover in the epidermis by interacting with vitamin D receptors on keratinocytes.

Salicylic Acid is approved for use in the following clinical indications:

Acne vulgaris: Topical management of acne.

Dermatitis: Bensal HP: Treatment of inflammation and irritation associated with dermatitis, including eczematoid conditions and complications associated with pyodermas; treatment of insect bites, burns, and fungal infections.

Hyperkeratotic skin disorders: Removal of excess keratin in various hyperkeratotic skin disorders and psoriasis (including affected areas of scalp, skin, and feet; treatment and removal of common and plantar warts).

Acne vulgaris (alternative agent):

Note: Reserve for patients who are not able to use a topical retinoid. For moderate to severe acne, may be used as part of an appropriate combination regimen .

Topical:

Salicylic acid 0.5% to 2%: OTC labeling: Apply thin layer to affected area 1 to 3 times daily. Because excessive drying may occur, products that are labeled for multiple daily doses should be initiated with 1 dose daily and increased gradually. Reduce to once daily or every other day if dryness or peeling occurs.

Cream, gel, liquid, pads: Salicylic acid ≤2%: Apply thin layer to affected area 1 to 3 times daily; reduce to once daily or every other day if dryness or peeling occurs.

Cleansers: Salicylic acid ≤2%: Use to cleanse skin 1 to 2 times daily.

Gel mask: Salicylic acid 0.5%: Use 1 to 2 times per week.

Callus and corns: Topical: Note: Before applying product, soak area in warm water for 5 minutes; dry area thoroughly, then apply medication.

Gel, liquid: Salicylic acid 13.9 to 17.6%: OTC labeling: Apply one drop to cover corn or callus. Let dry. Repeat once or twice daily until corn is removed for up to 14 days.

Pads: Salicylic acid 40%: OTC labeling: Apply directly over affected area; leave in place for 48 hours. Some products may be cut to fit area or secured with adhesive strips. May repeat procedure every 48 hours as needed for up to 14 days.

Dandruff, psoriasis, or seborrheic dermatitis: Topical: Note: Product-specific indications may vary; refer to manufacturer's labeling.

Cream, gel: Salicylic acid 2% or 3%: OTC labeling: Apply to affected area 1 to 4 times daily.

Shampoo: Salicylic acid 3%: OTC labeling: Apply to wet hair and gently massage into scalp; work up lather; rinse thoroughly. Use at least twice weekly.

Dermatitis: Topical: Ointment: Salicylic acid 3% : Apply twice daily. Reevaluate if improvement is not seen within 7 days.

Hyperkeratotic skin disorders: Topical:

Cream:

Salicylic acid 5.9%:  Apply twice daily to affected area and occlude overnight. Hydrate skin for at least 5 minutes prior to application. In areas where occlusion is difficult or impossible, application may be more frequent; once affected area becomes clear, occasional use will maintain remission.

Salicylic acid 6% or 10%:  Apply daily to affected area before bedtime. Hydrate skin for at least 5 minutes prior to application. Do not cover with occlusive dressings, clothing, or petrolatum-based products that may increase absorption. Wash off in morning. Once affected area becomes clear, occasional use will maintain remission.

Foam: Salicylic acid 6%: Apply to affected area twice daily

Gel: Salicylic acid 6%:  Apply daily to affected area and occlude overnight. Hydrate skin for at least 5 minutes prior to application. Wash off in morning. Once affected area becomes clear, occasional use will maintain remission. If applying the gel to the scalp, initially wash off after 10 to 20 minutes, but may be left on for up to 1 hour if needed as treatment progresses; avoid contact with normal hair or skin.

Shampoo:

Salicylic acid 6%: To use as a concentrated scalp treatment, apply daily to affected areas of scalp while hair is dry. Leave on for 5 minutes; may gradually increase contact time to 1 hour. After treatment, wash hair thoroughly with water or nonmedicated shampoo. To use as a medicated shampoo, apply daily to scalp while hair is wet; work into a lather; leave on for several minutes, then rinse. Once affected area becomes clear, occasional use will maintain remission.

Salicylic acid 6%: Apply to scalp while hair is wet; work into a lather; leave on for several minutes, then rinse. Repeat as needed. Once affected area becomes clear, occasional use will maintain remission.

Warts: Topical:

Liquid, solution: Salicylic acid 26% to 28.5%: Adults: Soak wart in warm water for 5 minutes. Dry area thoroughly. Apply to entire wart surface, allow to dry, and then apply a second time. Avoid contact with surrounding skin. Continue therapy once or twice daily. Resolution may be expected after 4 to 6 weeks; some warts may take longer to remove.

Liquid: Salicylic acid 17%: OTC labeling: Soak wart in warm water for 5 minutes. Dry area thoroughly. Apply 1 drop to cover wart. Let dry. Repeat once or twice daily until wart is removed for up to 12 weeks.

Pads: Salicylic acid 40%: OTC labeling: Soak wart in warm water for 5 minutes. Dry area thoroughly. Apply medicated pad directly over wart and secure firmly to skin. Repeat every 48 hours as needed until wart is removed for up to 12 weeks.

Topical liquid, gel,lotion, cream, aerosol, soap, strips,pads,disk, plaster,patch.

0.5%, 1%, 2%, 3%, 6%, 12.6%, 13.6%,15 %, 16.7%,17%, 17.6%, 26%, 27.5%, 40 %.

Topical liquid, gel, lotion, cream, aerosol, soap, strips, pads, disk, plaster, patch.

• Dose Adjustment in Pediatric Patient:

Acne vulgaris, mild: Topical: Children ≥12 and Adolescents: OTC labeling: Note: Before using a topical OTC acne drug product for the first time, apply sparingly to 1 or 2 small affected areas for 3 days to test for sensitivity. If no discomfort occurs, follow directions for use as stated on specific product label.

Salicylic acid 0.5% to 2%: General dosing instructions: Apply thin layer to affected area 1 to 3 times daily. Because excessive drying may occur, products that are labeled for multiple daily doses should be initiated with 1 dose daily and increased gradually. Reduce to once daily or every other day if dryness or peeling occur.

Cream, gel, liquid, lotion, pads: Salicylic acid ≤2%: Apply thin layer to affected area 1 to 3 times daily; reduce to once daily or every other day if dryness or peeling occur

Cleansers: Salicylic acid ≤2%: Use to cleanse skin 1 to 2 times daily

Gel mask: Salicylic acid 0.5%: Use 1 to 2 times per week

Callus and corns: Topical: Children and Adolescents: Note: Approved ages and uses for over the counter products may vary; consult labeling for specific information.

Gel, liquid: Salicylic acid 13.9% to 17.6%: Apply one drop to cover corn or callus. Let dry. Repeat once or twice daily until corn is removed for up to 14 days.

Bandages/Discs/Pads/Removers: Salicylic acid 40%: Apply directly over affected area; leave in place for 48 hours. Some products may be cut to fit area or secured with adhesive strips. May repeat procedure every 48 hours as needed for up to 14 days.

Hyperkeratotic skin disorders: Topical: Note: Approved ages and uses for generic products may vary; consult labeling for specific information.

Cream, lotion: Salicylic acid 5% or 6%: Children ≥2 years and Adolescents: Apply daily to affected area before bedtime. Wash off in morning. Once affected area becomes clear, occasional use will maintain remission.

Foam: Salicylic acid 6%: Children ≥2 years and Adolescents: Apply to affected area twice daily

Gel: Salicylic acid 6%: Children ≥2 years and Adolescents: Apply daily to affected area and occlude overnight. Wash off in morning. Once affected area becomes clear, occasional use will maintain remission. If applying the gel to the scalp, initially wash off after 10 to 20 minutes, but may be left on for up to 1 hour if needed as treatment progresses; avoid contact with normal hair or skin.

Shampoo: Children ≥2 years and Adolescents:

Salicylic acid 6%: To use as a concentrated scalp treatment, apply daily to affected areas of scalp while hair is dry. Leave on for 5 minutes; may gradually increase contact time to 1 hour. After treatment, wash hair thoroughly with water or nonmedicated shampoo. To use as a medicated shampoo, apply daily to scalp while hair is wet; work into a lather; leave on for several minutes, then rinse. Once affected area becomes clear, occasional use will maintain remission.

Salicylic acid 6%: Apply to scalp while hair is wet; work into a lather; leave on for several minutes, then rinse. Repeat as needed. Once affected area becomes clear, occasional use will maintain remission

Warts: Topical: Children and Adolescents: Note: Approved ages and uses for over the counter products may vary; consult labeling for specific information.

Liquid: Salicylic acid 17%: Apply 1 drop to cover wart. Let dry. Repeat once or twice daily until wart is removed for up to 12 weeks.

Bandages/Discs/Pads/Removers: Salicylic acid 40%: Apply medicated pad directly over wart and secure firmly to skin. Repeat every 48 hours as needed until wart is removed for up to 12 weeks.

Salicylic Acid may be contraindicated in the following conditions:

Hypersensitivity.

Concerns related to adverse effects:

• Hypersensitivity reaction: Rare but serious and potentially life-threatening allergic reactions or severe irritation have been reported with use of topical OTC benzoyl peroxide or salicylic acid containing products; it has not been determined if the reactions are due to the active ingredients (benzoyl peroxide or salicylic acid), the inactive ingredients, or a combination of both. Hypersensitivity reactions may occur within minutes to a day or longer after product use and differ from local skin irritation (redness, burning, dryness, itching, peeling or slight swelling) that may occur at the site of product application. Treatment should be discontinued if hives or itching develop; patients should seek emergency medical attention if reactions such as throat tightness, difficulty breathing, feeling faint, or swelling of the eyes, face, lips, or tongue develop. Before using a topical OTC acne product for the first time, consumers should apply a small amount to 1 or 2 small affected areas for 3 days to make sure hypersensitivity symptoms do not develop.

Concurrent drug therapy issues:

• Salicylates: Do not combine use of topical salicylic acid with use of other salicylates or drugs that can increase salicylate serum concentrations; systemic absorption following topical use may occur and lead to toxicity.

There is no sufficient scientific evidence traceable regarding use and safety of Salicylic Acid in concurrent use with alcohol.

Salicylates are excreted in breast milk after oral administration . Systemic absorption of topical salicylic acid occurs and varies depending on duration and vehicle (~9% to 25%) and is increased with occlusion. Consider adverse events associated with aspirin in nursing infants if significant systemic exposure occurs . For the topical treatment of warts, salicylic acid can be used in breast-feeding women (systemic absorption is usually minimal) (Butler 2014). Breast-feeding women should avoid use around the chest area to prevent exposure to the nursing child. Due to the potential for serious adverse reactions in the nursing infant, the manufacturer recommends a decision be made whether to discontinue nursing or the drug, taking into account the importance of treatment to the mother.

The adverse reactions related to Salicylic Acid can be categorized as

Common Adverse effects:

Irritation, Discomfort, Dryness, Peeling

The clinically relevant drug interactions of Salicylic Acid is briefly summarized here:

May increase the absorption of other topically applied medicines.

Dryness or irritation increases with other topical acne products.

May diminish the therapeutic effect of calcipotriol.

The most common side effects of Salicylic Acid include:

Irritation, Discomfort, Dryness, Peeling

Symptoms: Vomiting, headache, thirst, loss of hearing, tinnitus, lethargy, hyperpnoea, psychiatric disturbances and confusion.

Management: Supportive treatment including fluid and electrolyte replacement.

Pharmacodynamics:

Salicylic acid produces desquamation of hyperkeratotic epithelium via dissolution of the intercellular cement thereby causing swelling, softening, maceration, and desquamation of the cornified tissue. Salicylic acid is keratoplastic (corrects abnormal keratinisation) in low concentrations and keratolytic (causes peeling of the skin) in higher concentrations (1% or higher, depending on the vehicle).

Pharmacokinetics:

Absorption: Rapidly and efficiently absorbed percutaneously (65-85%). Time to peak plasma concentration: 6-12 hours.

Distribution: Distributed in the extracellular space. Crosses the placenta and enters breast milk. Plasma protein binding: 50-80%, to albumin.

Metabolism: Metabolised in the liver by microsomal enzymes.

Excretion: Mainly via urine (52% as salicyluric acid, 42% as salicylate glucuronides, 6% as salicylic acid).

1. https://www.uptodate.com/contents/Salicylic Acid -drug-information?search=Salicylic Acid &source=panel_search_result&selectedTitle=1~148&usage_type=panel&kp_tab=drug_general&display_rank=1#F154338
2. https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/022352s017lbl.pdf
3. https://www.medicaid.nv.gov/Downloads/provider/Salicylic Acid _2015-1215.pdf
4. https://www.mims.com/india/drug/info/Salicylic Acid ?type=full&mtype=generic#mechanism-of-action