Usage
This combination medication is prescribed for inflammatory dermatoses with secondary bacterial and fungal infections. It’s particularly effective against dermatophytosis, candidiasis, and bacterial infections susceptible to gentamicin.
Pharmacological Classifications:
- Clobetasol: Corticosteroid, topical anti-inflammatory, antipruritic
- Clotrimazole: Antifungal (imidazole derivative)
- Gentamicin: Antibiotic (aminoglycoside)
Mechanism of Action:
Clobetasol works by suppressing the immune response in the skin, reducing inflammation, itching, and redness. Clotrimazole inhibits ergosterol synthesis, a crucial component of fungal cell membranes. Gentamicin disrupts bacterial protein synthesis.
Alternate Names
No internationally recognized non-proprietary name exists for this combination. Regional variations in naming are also minimal since this is more commonly a compounded medication rather than a commercially available single product with a brand name. Some brand names that include two of the listed medications (betamethasone, clotrimazole and gentamicin) are Triderm, Lotriderm, and Canesten HC.
How It Works
Pharmacodynamics: Clobetasol exerts its anti-inflammatory, antipruritic, and vasoconstrictive effects by binding to glucocorticoid receptors. Clotrimazole alters fungal cell membrane permeability, ultimately leading to fungal cell death. Gentamicin binds to the bacterial 30S ribosomal subunit, inhibiting protein synthesis and causing bacterial cell death.
Pharmacokinetics:
- Clobetasol: Topically applied clobetasol has limited systemic absorption. When absorbed, it is metabolized primarily in the liver and excreted by the kidneys.
- Clotrimazole: Minimal systemic absorption occurs with topical application.
- Gentamicin: Negligible systemic absorption after topical application on intact skin. Systemic absorption increases significantly with application to large areas of broken or damaged skin, burns or to denuded or ulcerated areas. Systemic absorption is also higher on body areas with thinner stratum corneum and from under occlusion. When absorbed systemically, it’s excreted primarily by the kidneys.
Mode of Action (at cellular/molecular level): Clobetasol: Binds to glucocorticoid receptors in the cytoplasm, translocates to the nucleus, and modulates gene expression. Clotrimazole: Inhibits the enzyme 14-alpha-demethylase, preventing ergosterol biosynthesis in fungi. Gentamicin: Irreversibly binds to the 30S ribosomal subunit, interfering with the decoding site and causing misreading of mRNA.
Elimination Pathways: Clobetasol: Hepatic metabolism and renal excretion. Clotrimazole: Primarily fecal excretion (unabsorbed drug); minimally metabolized hepatically if absorbed. Gentamicin: Primarily renal excretion (when absorbed systemically).
Dosage
Standard Dosage
Adults:
Apply a thin layer to the affected skin area twice daily. Do not exceed 50g/week. Limit usage to a maximum of 2 weeks for most dermatoses.
Children:
Use in children under 12 is generally not recommended due to increased risk of HPA axis suppression with prolonged or extensive use. If use is deemed unavoidable, limit use to 5 days with careful monitoring by physician.
Special Cases:
- Elderly Patients: Use with caution as skin thinning and impaired drug clearance are possible.
- Patients with Renal Impairment: Gentamicin’s systemic absorption can be increased in areas with skin barrier disruption, so caution is necessary. Dose adjustments may be necessary in the case of significant skin barrier impairment.
- Patients with Hepatic Dysfunction: Clobetasol is metabolized by the liver, so use cautiously. Monitor for systemic side effects.
- Patients with Comorbid Conditions: Consider patient specific conditions (Diabetes, HPA axis dysregulation).
Clinical Use Cases
This topical combination medication is not indicated for systemically treated conditions that require intubation, surgical procedures, mechanical ventilation, or ICU care, or acute emergencies.
Dosage Adjustments
Adjustments are based on individual patient response, tolerance, and the severity of the condition. Consider renal/hepatic function when appropriate.
Side Effects
Common Side Effects:
Burning, stinging, itching, dryness, erythema, skin atrophy, hypopigmentation, telangiectasia.
Rare but Serious Side Effects:
Allergic contact dermatitis, folliculitis, hypertrichosis, HPA axis suppression (especially in children or with prolonged use), Cushing’s syndrome (with systemic absorption), glaucoma, cataracts (with ocular exposure). Ototoxicity and nephrotoxicity (very rare with topical use of gentamicin, except on open wounds, over wide areas, or for prolonged periods).
Long-Term Effects:
Skin atrophy, striae, telangiectasia, hypopigmentation.
Adverse Drug Reactions (ADR):
Severe allergic reactions, skin infections (secondary to immunosuppression).
Contraindications
Hypersensitivity to any component. Rosacea, acne, perioral dermatitis. Viral, fungal, or mycobacterial skin infections (unless specifically prescribed for mixed infections). Tuberculosis of the skin. Vaccinia, varicella.
Drug Interactions
Clotrimazole may interact with certain other antifungal agents like nystatin if applied on the same site. No other drug interactions are known.
No other clinically significant drug interactions are typically seen with topical application if skin integrity is maintained and application site is not extensive.
Pregnancy and Breastfeeding
Clobetasol is a Pregnancy Category C drug. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Safety during breastfeeding is not established. It is unknown if clobetasol is excreted in breast milk. It is advisable to use caution and seek advice from physician before using.
Drug Profile Summary
- Mechanism of Action: See “How It Works” above.
- Side Effects: See “Side Effects” above.
- Contraindications: See “Contraindications” above.
- Drug Interactions: See “Drug Interactions” above.
- Pregnancy & Breastfeeding: Category C (Clobetasol). Use with caution.
- Dosage: Apply a thin layer twice daily. Do not exceed 50g/week. Maximum 2 weeks for most dermatoses.
- Monitoring Parameters: Monitor for local and systemic side effects. Monitor growth in children.
Popular Combinations
This combination itself is sometimes considered a popular combination. However, if individual components are considered, then other combinations may be found depending on the clinical picture. If bacterial infection is not the cause of skin disease, then a combination of betamethasone + clotrimazole is a suitable alternative.
Precautions
See above for detailed information under various sections including side effects and contraindications.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Clobetasol + Clotrimazole + Gentamicin?
A: Apply a thin layer to the affected area twice daily. Do not exceed 50g per week. Duration should generally not exceed 2 weeks.
Q2: Can this combination be used in children?
A: Not recommended for children under 12. If unavoidable, limit use to 5 days with close monitoring by physician.
Q3: What are the common side effects?
A: Burning, stinging, itching, dryness, erythema, skin atrophy, hypopigmentation, telangiectasia.
Q4: Is it safe to use during pregnancy or breastfeeding?
A: Clobetasol is Pregnancy Category C. Use with caution during pregnancy only if the potential benefit outweighs the potential risk to the fetus. Safety during breastfeeding is not established. Consult with a physician.
Q5: What conditions is this combination effective against?
A: Inflammatory dermatoses complicated by secondary bacterial and/or fungal infections.
Q6: Can I use this if I am allergic to other antibiotics?
A: If you have any known allergies to medications, especially to antibiotics or topical corticosteroids, inform your prescribing physician. An allergy to gentamicin, clobetasol, or clotrimazole contraindicates the use of this combination.
Q7: What should I do if my condition doesn’t improve?
A: Consult your physician. They may adjust the treatment plan or prescribe an alternative therapy.
Q8: Can I cover the treated area with a bandage?
A: Generally no. Occlusive dressings can enhance absorption, increasing the risk of systemic side effects. Use only if specifically directed by your physician.
Q9: How should I apply the medication?
A: Wash your hands thoroughly. Clean and dry the affected area. Apply a thin layer of the medication and gently rub it in. Wash your hands again after application unless treating the hands themselves.
