Methoxsalen (Topical Route)
Original Article: http://www.mayoclinic.com/health/drug-information/DR600911
US Brand Names
Canadian Brand Names
Methoxsalen belongs to the group of medicines called psoralens. It is used along with ultraviolet light (found in sunlight and some special lamps) in a treatment called psoralen plus ultraviolet light A (PUVA) to treat vitiligo, a disease in which skin color is lost. Methoxsalen may also be used for other conditions as determined by your doctor.
Methoxsalen is available only with a prescription and is to be administered by or under the direct supervision of your doctor.
Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, topical methoxsalen is used in certain patients with the following medical conditions:
- Alopecia areata
- Inflammatory dermatoses
- Lichen planus
- Mycosis fungoides
- Need to increase tolerance of skin to sunlight
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Methoxsalen is a very strong medicine that increases the skin's sensitivity to sunlight. In addition to causing serious sunburns if not properly used, it has been reported to increase the chance of skin cancer. Also, like too much sunlight, PUVA can cause premature aging of the skin. Therefore, methoxsalen should be used only as directed and should not be used simply for suntanning. Before using this medicine, be sure that you have discussed its use with your doctor.
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of methoxsalen in children up to 12 years of age with use in other age groups.
Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of topical methoxsalen in the elderly with use in other age groups.
|All Trimesters||C||Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.|
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Allergy to sunlight (or family history of) or
- Infection or
- Lupus erythematosus or
- Porphyria or
- Skin cancer (history of) or
- Skin conditions (other)—Use of PUVA may make the condition worse
- Heart or blood vessel disease (severe)—The heat or prolonged standing associated with each light treatment may make the condition worse
Eating certain foods while you are using 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.
Use this medicine only under the direct supervision of your doctor.
After UVA exposure, wash the treated area of skin with soap and water. Then use a sunscreen or wear protective clothing to protect the area.
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 topical solution dosage form:
- For vitiligo:
- Adults and children 12 years of age and over—Apply to the affected area of the skin and allow to dry for one to two minutes, then apply again within two to two and one-half hours before UVA exposure.
- Children under 12 years of age—Use and dose must be determined by your doctor.
- For vitiligo:
It is important that you visit your doctor as directed for treatments and to have your progress checked.
This medicine increases the sensitivity of the treated areas of your skin to sunlight. Therefore, exposure to the sun, even through window glass or on a cloudy day, could cause a serious burn. After each light treatment, thoroughly wash the treated areas of your skin. Also, if you must go out during daylight hours, cover the treated areas of your skin for at least 12 to 48 hours following treatment by wearing protective clothing or a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.
The treated areas of your skin may continue to be sensitive to sunlight for some time after treatment with this medicine. Use extra caution for at least 72 hours following each treatment if you plan to spend any time in the sun. In addition, do not sunbathe anytime during your course of treatment with methoxsalen.
This medicine may cause your skin to become dry or itchy. However, check with your doctor before applying anything to your skin to treat this problem.
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Blistering and peeling of skin
- Reddened, sore skin
- Swelling, especially of the feet or lower legs
There is an increased risk of developing skin cancer after use of methoxsalen. You should check the treated areas of your body regularly and show your doctor any skin sores that do not heal, new skin growths, and skin growths that have changed in the way they look or feel.
Premature aging of the skin may occur as a result of prolonged methoxsalen therapy. This effect is permanent and is similar to the result of sunbathing for long periods of time.
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.