Methoxsalen - Oral

Methoxsalen is used in combination with a specific kind of light therapy (controlled exposure to long wavelength ultraviolet radiation) to treat certain types of skin problems such as vitiligo (loss of skin colour in patches) and psoriasis (a type of skin disease that is caused by itchy patches of thick, red skin and silvery scales).

Take Methoxsalen exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

Take with meals or with a glass of milk before the light radiation therapy. Try to take it at the same time each day.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the course of the treatment depending on your condition and response to the medication.

Methoxsalen must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed to do so by the doctor.

Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.

Alert your doctor if you have the following conditions:

• current or history of skin cancer
• systemic lupus erythematosus (autoimmune disease that causes inflammation of certain organs in the body)
• albinism (lack of pigment in the skin, hair or eyes)
• porphyria (an inherited disorder that causes skin or nervous system abnormalities)
• absence of lens in the eyes

as Methoxsalen may not be suitable for you.

Inform your doctor if you have the following conditions:

• severe anaemia (low red blood cell count in the body)
• liver disease
• heart disease
• eye disease
• previous x-ray therapy
• previous arsenic therapy
• history of spleen removal
• blood clotting problems

Let your doctor know if you are pregnant or breastfeeding.

Both men and women must use proven birth control methods during Methoxsalen therapy. You may wish to discuss other reliable methods of birth control with your doctor.

Be sure to check with your doctor or pharmacist before giving this medicine to the elderly. Elderly people may be more sensitive to the side effects.

Why is it important to keep my appointments with the doctor?

Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.

• Routine tests (e.g. complete blood count, liver function, kidney function) may be done before and while you are being treated with this medicine. Your doctor will advise you about how often you need to have these tests.
• Regular monitoring of signs and symptoms of skin cancer may also be needed.

Methoxsalen may cause any of the following side effects: nausea, headache, dizziness, difficulty sleeping, nervousness, and depression.

This medicine may also increase your sensitivity to sunlight. Apply sunscreen, wear protective clothing, and sunglasses when going outdoors, even when indoors or near windows. Avoid direct or prolonged exposure to sunlight and UV lamps before and after treatment.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:

• severe skin irritation, sunburn
• skin lump or growth, change in colour or size of a mole
• problems with your eyesight such as changes in vision

Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.

Inform your doctor and pharmacist if you are taking any of these medicines:

• tolbutamide (medicine for diabetes)
• griseofulvin (medicine to treat fungal infection)
• water pills or medicines for water retention e.g. chlorothiazide, hydrochlorothiazide
• certain antibiotics e.g. sulfamethoxazole, tetracycline, ciprofloxacin, nalidixic acid
• other medicines for psoriasis e.g. anthralin, coal tar or its derivatives

This list does not include all medicines that may interact with Methoxsalen.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements, and medicines that you buy without a prescription.

Avoid alcohol.

Avoid foods that contain high amounts of a substance called psoralen such as limes, figs, parsley, celery, cloves, lemon, mustard, and carrots.

Store in a cool, dry place away from the reach of children.

Medicines must not be used past the expiry date.