1. Clinical Overview
A topical combination product primarily used in the management of chronic, non-infectious dermatoses characterized by hyperkeratosis, scaling, and inflammation, such as psoriasis and seborrheic dermatitis. Coal Tar acts as an anti-inflammatory, antipruritic, and antimitotic agent, while Salicylic Acid provides keratolytic and mild anti-inflammatory effects. This combination is a cornerstone of topical therapy in the Indian market for its efficacy, cost-effectiveness, and long history of use.
| Onset | Duration | Bioavailability |
|---|---|---|
| Therapeutic effects on scaling and itching may be observed within 3-7 days of regular application. Full anti-inflammatory and antipsoriatic effects may take 2-4 weeks. | Local effects persist for approximately 8-12 hours post-application. Continuous daily application is required for maintenance therapy in chronic conditions. | Topical bioavailability is low and variable. Systemic absorption of coal tar components (polycyclic aromatic hydrocarbons) and salicylic acid is minimal when applied to intact skin over limited body surface area (<20%). Absorption increases with application to inflamed, broken skin, or large areas. |
2. Mechanism of Action
The combination works synergistically. Coal Tar reduces epidermal hyperproliferation and dermal inflammation seen in psoriasis and dermatitis. It suppresses DNA synthesis, reduces mitotic activity in the basal layer, and exhibits anti-itch properties. Salicylic Acid facilitates the penetration of coal tar by breaking down intercellular keratinocyte bonds (desmogleins) and dissolving the stratum corneum. It also has mild anti-inflammatory properties.
3. Indications & Uses
- Chronic Plaque Psoriasis (Scalp and Body)
- Scalp Psoriasis
- Seborrheic Dermatitis (Scalp and Body)
- Atopic Dermatitis (Eczema) with significant scaling
4. Dosage & Administration
Adult Dosage: Apply a thin layer to affected areas once or twice daily, typically at bedtime. For scalp: Apply, leave on for 5-10 minutes, then lather and rinse thoroughly. Frequency may be reduced to alternate days or 2-3 times per week for maintenance.
Administration: 1. Wash and dry the affected area. 2. Apply a thin film and rub gently until absorbed. 3. Avoid contact with eyes, mucous membranes, genitalia, and face unless directed by a physician. 4. For scalp use, part hair and apply directly to scalp, not hair. 5. May be occluded with a bandage or shower cap for scalp to enhance efficacy, but this increases absorption and risk of irritation. 6. Wash hands thoroughly after application. 7. Can stain clothing and bedding; use old fabrics.
5. Side Effects
Common side effects may include:
- Local Skin Irritation (burning, stinging)
- Folliculitis
- Skin Dryness
- Temporary Hair Discoloration (blond/grey hair may turn yellowish)
- Staining of skin, nails, hair, and fabrics
- Unpleasant Odor
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other Topical Salicylic Acid Preparations or Keratolytics (e.g., Urea, Lactic Acid) | Increased risk of excessive skin dryness, irritation, and systemic salicylate absorption. | Major |
| Topical Tretinoin, Benzoyl Peroxide, or other strong irritants | Additive skin irritation and inflammation. | Major |
| Photosensitizing Drugs (e.g., Tetracyclines, Fluoroquinolones, Thiazides, Phenothiazines) | Increased risk of severe phototoxic reactions. | Major |
| Oral Anticoagulants (e.g., Warfarin) | Systemically absorbed salicylic acid may potentiate anticoagulant effect and increase bleeding risk. | Moderate |
| Oral Hypoglycemics (e.g., Sulfonylureas) | Salicylates may potentiate hypoglycemic effect. | Moderate |
| Methotrexate | Theoretical risk of increased hepatotoxicity; caution advised. | Moderate |
7. Patient Counselling
- DO apply a thin layer only to affected areas.
- DO wash hands before and after application.
- DO use sun protection (SPF 30+ broad-spectrum) on treated areas when going outdoors, as this medicine makes skin more sensitive to sun.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DON'T apply to face, eyes, mouth, genital areas, or on broken/infected skin unless directed.
- DON'T use tight occlusive dressings unless advised by doctor.
- DON'T use other medicated skin products (like acne washes, other psoriasis creams) without asking your doctor.
- DON'T use on children without explicit pediatrician/dermatologist advice.
8. Toxicology & Storage
Overdose: Topical Overdose (excessive application): Severe local irritation, blistering, peeling. Systemic Salicylate Toxicity (Salicylism): Tinnitus, hearing loss, vertigo, headache, confusion, drowsiness, hyperventilation, nausea, vomiting, diarrhea, sweating, fever. Severe: Metabolic acidosis, seizures, coma, respiratory failure, cardiovascular collapse.
Storage: Store at room temperature (15-25°C). Keep the container tightly closed. Protect from light and moisture. Do not freeze. Keep out of reach and sight of children. Do not store in the bathroom. Discard any unused product 4 weeks after opening, or as per manufacturer's expiry date, whichever is earlier.