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Overview: Methoxsalen is used to help manage skin symptoms of a type of cancer called cutaneous T-cell lymphoma (CTCL) or severe psoriasis. Methoxsalen, when activated by ultraviolet A (UVA) light, interacts with DNA to help slow down or stop the growth of abnormal skin cells in these conditions. Methoxsalen increases your sensitivity to sunlight and can cause your skin to be severely sunburned, blistered, or swollen when exposed. Follow all instructions for avoiding sunlight, such as wearing the right clothing and sunglasses and applying sunscreen.

Uses

What is methoxsalen used for?

Methoxsalen is commonly used to help manage symptoms of the following conditions when other treatments have not worked.

  • Cutaneous T-cell lymphoma (CTCL), which is a type of cancer that affects the skin 
  • Severe psoriasis, which is a skin condition 

These uses may vary, depending on the specific methoxsalen product prescribed.

Methoxsalen may also be used for other conditions as determined by your health care provider.

How does methoxsalen work (mechanism of action)?

Methoxsalen, when activated by ultraviolet A (UVA) light, interacts with DNA. This can help slow down or stop the growth of abnormal skin cells in conditions like psoriasis or cutaneous T-cell lymphoma. 

How is methoxsalen supplied (dosage forms)?

Brands and other names

  • 8-MOP
  • Oxsoralen-Ultra
  • Uvadex

Dosage forms and strengths

  • 10 mg oral capsules

Methoxsalen is also available in an injectable form that is given by a health care provider.

How should I store methoxsalen?

Oral Capsule. Methoxsalen capsules should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when you’re transporting it. Store it in a cool, dry place.

Injection Liquid. Injectable methoxsalen is usually given by a health care provider in a hospital or clinic. You will not store it at home.

Side Effects

What are the most common side effects of methoxsalen?

The most common side effects of methoxsalen are listed below. These side effects may vary, depending on the condition that is being treated. Tell your health care provider if you have any of these side effects that bother you.

  • Sensitivity to sunlight (see below)
  • Nausea 
  • Itchy, red skin 
  • Low blood pressure 

There may be other side effects of methoxsalen that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of methoxsalen?

While less common, the most serious side effects of methoxsalen are described below, along with what to do if they happen.

Severe Allergic Reactions. Methoxsalen may cause allergic reactions, which can be serious. Stop using methoxsalen and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Sensitivity to Sunlight. Your skin may be very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds, while you are using methoxsalen. This is called photosensitivity. Use sunscreen and wear a hat, sunglasses, and clothes that cover your skin if you need to be in the sunlight. Exposure to this kind of light, even for a short time, can cause your skin to be severely sunburned, blistered, or swollen. Tell your health care provider right away if you have any of these symptoms.

Cancer. Methoxsalen can cause a new cancer to develop or cause a previously treated cancer to recur. Tell your health care provider about any new symptoms that you may get. Regularly check your skin and tell your health care provider right away if you have any small growths or sores that will not heal. These areas need to be checked by your health care provider to rule out skin cancer.

Cataracts. Methoxsalen may increase the risk of cloudiness in your eye (cataracts). Follow your health care provider’s instructions carefully and keep all appointments to have your eyes checked before and while using methoxsalen. Tell your health care provider right away if you have the following symptoms of cataracts.

  • Cloudy or blurred vision
  • Changes in how you see colors
  • Seeing halos around lights
  • Problems with glare

Warnings & Precautions

Who should not use methoxsalen?

Allergies to Ingredients. People who are allergic to any of the following should not use methoxsalen.

  • Methoxsalen
  • 8-MOP
  • Oxsoralen-Ultra
  • Uvadex
  • Any other medicine known as a psoralen
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific methoxsalen products they stock.

Light-Sensitive Conditions. Methoxsalen should not be used if you have a condition that makes you sensitive to light or requires you to stay out of the sun, such as lupus, porphyria, or albinism.

Eye Problems. Methoxsalen should not be used if you are missing the lens of one or both eyes, a condition known as aphakia. Methoxsalen can increase the risk of serious eye problems if you have this condition. 

Skin Cancer. Methoxsalen capsules should not be taken if you have or have had certain types of skin cancer, such as melanoma or invasive squamous cell carcinoma. 

Problems With Photopheresis. Methoxsalen injections should not be used if you have a condition or issue that makes the photopheresis procedure unsafe for you. 

What should I know about methoxsalen before using it?

Do not use methoxsalen unless it has been prescribed to you by a health care provider. Use it as prescribed.

Do not share methoxsalen with other people, even if they have the same condition as you. It may harm them.

Keep methoxsalen out of the reach of children.

For methoxsalen injections, the medicine will be given through a process called photopheresis. This is when a machine removes some of your blood to separate out your white blood cells. These blood cells are exposed to methoxsalen and ultraviolet A (UVA) light in the machine. Then the treated blood cells are injected through your vein (intravenous) back into your body. 

If you are taking methoxsalen capsules, you should take the medicine by mouth with low-fat food or milk to reduce nausea. Then, about two hours later, you will receive UVA light treatment in a special chamber. 

Do not sunbathe for 24 hours before using methoxsalen and UVA treatment. Having a sunburn may prevent your health care provider from being able to tell how well the treatment is working.   

Avoid all exposure to sunlight, including through window glass or cloud cover, for 24 hours after receiving photopheresis treatment or for at least eight hours after taking methoxsalen capsules. Exposure to sunlight can cause severe sunburns, blisters, and swelling. It may also cause premature aging of the skin and increase your risk of skin cancer. 

If you cannot avoid sun exposure after treatment, cover exposed skin with clothing, a hat, and gloves, and use a sunscreen that protects against UVA radiation (SPF 15 or higher). Make sure to include your lips so they do not burn.

Wear UVA-absorbing, wraparound sunglasses for 24 hours after treatment to protect against sunlight, including through window glass. Ordinary sunglasses are not enough, since sunlight can enter from the sides. It is important to wear eye protection to limit your risk of getting cataracts. Talk to your health care provider if you have questions.

Do not sunbathe for 48 hours after using methoxsalen and UVA treatment. Sunbathing can cause you to burn faster and more severely. 

What should I tell my health care provider before using methoxsalen?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if methoxsalen is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Skin cancer
  • Eye problems, such as cataracts or loss of eye lenses
  • Liver or kidney problems
  • Heart or blood pressure problems 

Radiation. Tell your health care provider if you have any planned radiation treatments or had them in the past. Using methoxsalen may raise the risk of cancer. 

Arsenic Therapy. Tell your health care provider if you have been treated with arsenic in the past. Using methoxsalen may raise the risk of cancer. 

Other Medicines and Supplements. Methoxsalen may interact with other medicines and supplements. Before using methoxsalen, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. Methoxsalen may harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant. 

Breastfeeding. It is not known if methoxsalen passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should stop breastfeeding or stop methoxsalen.

Interactions

Does methoxsalen interact with foods or drinks?

There are no known interactions between methoxsalen and foods or drinks.

It is unknown if drinking alcohol will affect methoxsalen.

Does methoxsalen interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before using methoxsalen.

  • Anthralin, which is a cream or shampoo used for psoriasis
  • Coal tar, which is a medicine used on your skin or scalp for certain skin conditions
  • Griseofulvin, which is a medicine used to treat fungal infections
  • A phenothiazine, such as chlorpromazine or prochlorperazine (Compro and others), which is a medicine that may be used to treat certain mental health conditions or severe nausea and vomiting
  • A sulfonamide or “sulfa” medicine, such as sulfadiazine silver, sulfamethoxazole, or sulfasalazine 
  • A sulfonylurea, such as glimepiride, glipizide, or glyburide, which is a medicine used to treat type 2 diabetes
  • A tetracycline, such as doxycycline, minocycline, omadacycline (Nuzyra), sarecycline (Seysara), or tetracycline, which is a medicine used to treat infections or other conditions
  • A fluoroquinolone antibiotic, such as ciprofloxacin, levofloxacin, or moxifloxacin, which is a medicine used to treat bacterial infections
  • A thiazide diuretic, such as chlorthalidone, hydrochlorothiazide, or indapamide, which is a medicine commonly used to lower blood pressure

This may not be a complete list of medicines that can interact with methoxsalen. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much methoxsalen?

If you or someone else has used too much methoxsalen, stay out of the sunlight and get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of methoxsalen?

If you forget to take methoxsalen capsules before your scheduled ultraviolet light treatment, call your health care provider for advice on what to do. Do not take double or extra doses of methoxsalen. 

If you miss an appointment to get methoxsalen and UVA light treatment, call to make another appointment as soon as possible.