Vitilen

Indications

Methoxsalen (8-methoxypsoralen) is used together with controlled ultraviolet A (UVA) light, a treatment called PUVA, for severe psoriasis that has not responded to other treatments, and for vitiligo (white patches caused by loss of skin pigment). It is also used in a specialised hospital procedure (extracorporeal photopheresis) for some skin lymphomas. It comes as capsules and as a lotion or solution applied to the skin.

How It Works

Methoxsalen is a psoralen, a substance that makes skin cells very sensitive to UVA light. When the skin is exposed to UVA after taking or applying Methoxsalen, the drug binds to the DNA of fast-dividing skin cells and slows their growth, which clears psoriasis plaques. In vitiligo, the treatment stimulates pigment cells (melanocytes) to produce colour again.

Dosage and Administration

Methoxsalen is used only under the supervision of a dermatologist, and the dose is as prescribed. Capsules are usually taken a set time (often about 1 to 2 hours) before a measured UVA session, according to body weight and skin type. The lotion is applied to small areas as directed by the doctor before controlled UVA exposure; never use natural sunlight to treat yourself. Treatment sessions are given a few times a week, with at least 48 hours between sessions. Never take or apply it more often than prescribed.

Interactions

• Other medicines that make the skin sensitive to light, such as Tetracyclines, Fluoroquinolones, Thiazide diuretics, Griseofulvin, Sulphonamides, phenothiazines and some dyes: increase the risk of severe burns.
• Coal tar and other topical psoralens: add to light sensitivity.

Tell your doctor about all medicines, herbal products and cosmetics you use.

Contraindications

Do not use Methoxsalen if you are allergic to it, have diseases made worse by light (such as lupus, porphyria or albinism), have had melanoma or have a history of other skin cancers or high risk of them, have cataracts or no lens in the eye (aphakia), or are a child under 12, unless the specialist decides otherwise.

Side Effects

Common side effects include nausea (with capsules), itching, redness, dry skin and sunburn-like reactions. Long-term PUVA treatment increases the risk of skin ageing, skin cancers including melanoma, and cataracts.

Get urgent medical help if you develop severe burning, painful blisters or swelling of the skin, fever after treatment, signs of an allergic reaction such as swelling of the face or difficulty breathing, or yellowing of the skin or eyes. Report any new or changing moles promptly.

Pregnancy and Lactation

Methoxsalen is generally not used during pregnancy. It is not known how much passes into breast milk, and breastfeeding is not recommended during treatment. Discuss contraception and pregnancy plans with your doctor.

Precautions and Warnings

After each dose and on treatment days, avoid all sunlight for at least 24 hours: wear protective clothing and sunscreen on exposed skin, and wear UVA-blocking wrap-around sunglasses for 24 hours, even indoors near windows. Regular eye and skin checks are needed. Use with care in liver disease. Do not use sunbeds.

Overdose

Taking too much or being exposed to too much UVA can cause severe burns and blistering. Stay in a dark room for at least 24 hours and seek medical help straight away.

Therapeutic Class

Psoralen, photosensitising agent for PUVA therapy.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.