Usage
Coal tar is prescribed for inflammatory skin conditions like psoriasis, seborrheic dermatitis (dandruff), and eczema. It’s classified as a keratoplastic, keratolytic, and antipruritic agent. Coal tar slows rapid skin cell growth, reduces inflammation, and relieves itching.
Alternate Names
Liquor carbonis detergens (LCD), pix lithanthracis
How It Works
Pharmacodynamics: Coal tar suppresses epidermal cell proliferation and has anti-inflammatory and antipruritic effects. The exact mechanism is not fully understood but involves multiple pathways, possibly including inhibiting DNA synthesis and altering keratinocyte differentiation.
Pharmacokinetics: Coal tar is primarily applied topically. Absorption is minimal with topical application, but some systemic absorption can occur with extensive use or high concentrations. Metabolism and elimination pathways are not well-defined for topical application.
Dosage
Standard Dosage
Adults:
Creams/ointments/lotions/gels: Apply a thin layer to the affected area 1-4 times daily.
Shampoo: Massage into wet scalp, leave for several minutes, and rinse thoroughly. Use 1-2 times per week.
Children:
Generally, similar dosing to adults, but always follow product-specific recommendations. For children under 12, dilution with water might be advised (consult product instructions or physician).
Special Cases:
- Elderly Patients: Similar dosing to adults but start with the lowest concentration and monitor closely for skin irritation.
- Patients with Renal Impairment: No specific dose adjustments are typically needed for topical application.
- Patients with Hepatic Dysfunction: No specific dose adjustments are typically needed for topical application.
- Patients with Comorbid Conditions: No specific adjustments unless the comorbidity involves the affected skin area.
Clinical Use Cases
Coal tar is not typically used in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU, or emergency situations. Its primary use is for the topical management of dermatological conditions.
Dosage Adjustments
Adjustments may be necessary based on individual response and tolerability. Start with the lowest concentration and increase as needed.
Side Effects
Common Side Effects
Skin irritation, burning, stinging, redness, photosensitivity (increased sun sensitivity), folliculitis (inflammation of hair follicles), staining of skin and clothing.
Rare but Serious Side Effects
Allergic contact dermatitis (rash, itching, blistering), skin discoloration changes.
Long-Term Effects
Prolonged use may increase the risk of skin cancer with excessive sun exposure.
Adverse Drug Reactions (ADR)
Severe allergic reactions are rare but can occur.
Contraindications
- Acute, inflamed, broken, or infected skin.
- Pustular psoriasis.
- Hypersensitivity to coal tar.
Drug Interactions
No significant drug interactions are typically reported with topical coal tar. However, concomitant use of other topical medications on the same area may increase the risk of irritation. Photosensitizing medications may increase the risk of sunburn.
Pregnancy and Breastfeeding
Topical coal tar is generally considered safe during pregnancy and breastfeeding when used as directed. However, minimize use and consult with a healthcare professional before use.
Drug Profile Summary
- Mechanism of Action: Reduces epidermal cell turnover, anti-inflammatory, antipruritic.
- Side Effects: Skin irritation, photosensitivity, staining.
- Contraindications: Inflamed/broken skin, hypersensitivity.
- Drug Interactions: Minimal. Photosensitizing medications.
- Pregnancy & Breastfeeding: Generally considered safe for topical use.
- Dosage: Topical application 1-4 times daily (variable by product).
- Monitoring Parameters: Observe the affected skin for treatment response and adverse effects.
Popular Combinations
Coal tar is sometimes combined with salicylic acid or corticosteroids in topical formulations for enhanced efficacy.
Precautions
- Avoid contact with eyes, mucous membranes, and genitals.
- Wash hands after application.
- Protect treated skin from sunlight.
- Monitor for signs of skin irritation or allergic reaction.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Coal Tar?
A: Dosage varies by product formulation (cream, ointment, shampoo, etc.). Generally, apply a thin layer to affected skin 1-4 times per day. Shampoos are typically used 1-2 times per week. Refer to specific product instructions.
Q2: How long does it take for Coal Tar to work?
A: Improvement may be seen within a few weeks, but several months may be needed for optimal results.
Q3: Can Coal Tar be used on the face?
A: Use with caution on the face due to the risk of irritation. Avoid the eye area.
Q4: Does Coal Tar stain clothing?
A: Yes, coal tar can stain clothing and bedding. Use with care and allow to dry completely before dressing.
Q5: Can pregnant women use Coal Tar?
A: Topical coal tar is generally considered safe during pregnancy when used as directed, but it’s always best to consult a physician.
Q6: Can Coal Tar interact with other medications?
A: Few drug interactions are reported. However, concomitant use of other topical medications on the same area may increase irritation.
Q7: What should I do if I experience skin irritation with Coal Tar?
A: Discontinue use and consult a physician.
Q8: Is Coal Tar safe for long-term use?
A: Long-term use is generally safe, but regular monitoring is recommended. Excessive sun exposure should be avoided due to the increased risk of skin cancer.
A: Coal tar is available as creams, ointments, lotions, shampoos, bath solutions, and gels.
