Proper Use

Drug information provided by: Merative, Micromedex®

Eating certain foods while you are taking methoxsalen may increase your skin's sensitivity to sunlight. To help prevent this, avoid eating limes, figs, parsley, parsnips, mustard, carrots, and celery while you are being treated with this medicine.

Methoxsalen usually comes with patient directions. Read them carefully before using this medicine.

This medicine may take 6 to 8 weeks to really help your condition. Do not increase the amount of methoxsalen you are taking or spend extra time in the sunlight or under an ultraviolet lamp. This will not make the medicine act any more quickly and may result in a serious burn.

If this medicine upsets your stomach:

  • Patients taking the hard gelatin capsules may take them with food or milk.
  • Patients taking the soft gelatin capsules may take them with low-fat food or low-fat milk.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (hard gelatin capsule):
    • For treating mycosis fungoides and psoriasis:
      • Adults and children 12 years of age and over—Dose is based on body weight and must be determined by your doctor. However, the usual dose is 0.6 mg per kilogram (kg) (0.27 mg per pound) of body weight taken two hours before UVA exposure. This treatment (methoxsalen and UVA) is given two or three times a week with the treatment spaced at least forty-eight hours apart.
      • Children up to 12 years of age—Dose must be determined by your doctor.
    • For vitiligo:
      • Adults and children 12 years of age and over—20 milligrams (mg) per day taken two to four hours before ultraviolet light A (UVA) exposure. This treatment (methoxsalen and UVA) is given two or three times a week with the treatment spaced at least forty-eight hours apart.
      • Children up to 12 years of age—Dose must be determined by your doctor.
  • For oral dosage form (soft gelatin capsule):
    • For psoriasis:
      • Adults and children 12 years of age and over—Dose is based on body weight and must be determined by your doctor. The usual dose is 0.4 mg per kg (0.18 mg per pound) of body weight taken one and one-half to two hours before UVA exposure. This treatment (methoxsalen and UVA) is given two or three times a week, with the treatment spaced at least forty-eight hours apart.
      • Children up to 12 years of age—Dose must be determined by your doctor.

Missed Dose

Call your doctor or pharmacist for instructions.

If you are late in taking, or miss taking, a dose of this medicine, notify your doctor so your light treatment can be rescheduled. Remember that exposure to sunlight or ultraviolet light must take place a certain number of hours after you take the medicine or it will not work. For patients taking the hard gelatin capsules, this is 2 to 4 hours. For patients taking the soft gelatin capsules, this is 1½ to 2 hours. If you have any questions about this, check with your doctor.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Portions of this document last updated: Feb. 01, 2024

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