1. Clinical Overview
Calcipotriol is a synthetic vitamin D3 analogue used topically for the treatment of plaque psoriasis. It acts as a modulator of keratinocyte differentiation and proliferation, and as an immunomodulator. In the Indian context, it is a first-line topical treatment for mild-to-moderate psoriasis and is widely available across various price points.
| Onset | Duration | Bioavailability |
|---|---|---|
| Clinical improvement typically observed within 1-2 weeks of treatment initiation. | Therapeutic effects persist for the duration of regular application; rebound may occur upon discontinuation. | Systemic absorption from topical application is low, estimated at <1% under normal use conditions. Absorption increases with application to inflamed skin, damaged skin, or under occlusion. |
2. Mechanism of Action
Calcipotriol is a synthetic analogue of calcitriol (1,25-dihydroxyvitamin D3). It binds to the intracellular vitamin D receptor (VDR) in keratinocytes and immune cells. The activated VDR complex translocates to the nucleus, binds to vitamin D response elements (VDREs), and modulates gene transcription. This leads to inhibition of keratinocyte proliferation, induction of normal keratinocyte differentiation, and suppression of the inflammatory T-cell mediated immune response characteristic of psoriasis.
3. Indications & Uses
- Mild to Moderate Chronic Plaque Psoriasis (Vulgaris)
4. Dosage & Administration
Adult Dosage: Apply a thin layer to affected areas once or twice daily. Maximum weekly dose should not exceed 100 grams of ointment/gel/cream or 60 mL of scalp solution.
Administration: Apply only to psoriatic plaques. Wash hands before and after application. Avoid application on the face, eyes, mouth, flexures (armpits, groin), and broken or inflamed skin unless prescribed. Do not occlude the treated area. For scalp use, part hair and apply solution directly to scalp.
5. Side Effects
Common side effects may include:
- Local skin irritation (burning, stinging, itching)
- Erythema (redness) at application site
- Dry skin
- Skin peeling
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other Topical Vitamin D Analogues (e.g., Tacalcitol) | Additive risk of hypercalcemia and local irritation. | Major |
| Topical Corticosteroids (e.g., Betamethasone) | Often used in combination (as fixed-dose products like Calcipotriol + Betamethasone dipropionate) for enhanced efficacy. Monitor for skin atrophy with potent steroids. | Moderate |
| Topical Salicylic Acid | Salicylic acid may inactivate calcipotriol. Avoid concurrent application to the same site. | Moderate |
| Oral Calcium Supplements / Vitamin D | Increased risk of hypercalcemia, especially with high doses. | Moderate |
| Thiazide Diuretics (e.g., Hydrochlorothiazide) | May increase risk of hypercalcemia by reducing renal calcium excretion. | Moderate |
7. Patient Counselling
- DO apply a thin layer only to the affected psoriatic plaques.
- DO wash your hands before and after application.
- DO use regularly as prescribed for best results; improvement may take 1-2 weeks.
- DON'T apply on the face, eyes, mouth, or in skin folds (armpits, groin).
- DON'T use more than the prescribed amount or frequency (max 100g/week).
- DON'T cover the treated area with airtight dressings (occlusion).
- DON'T use for any condition other than psoriasis.
8. Toxicology & Storage
Overdose: Topical overdose: Severe local irritation, erythema, peeling. Systemic overdose (from massive topical application): Symptoms of hypercalcemia - nausea, vomiting, constipation, lethargy, polydipsia, polyuria, dehydration, and in severe cases, cardiac arrhythmias and renal calcification.
Storage: Store at room temperature (15-25°C). Protect from light and heat. Do not freeze. Keep the tube or bottle tightly closed. Keep out of reach and sight of children.