Methoxsalen | Side Effects, Dosage, Uses & More
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Generic Name:

methoxsalen, Oral capsule

All Brands

  • Oxsoralen (Discontinued)
  • 8-MOP
A discontinued drug is a drug that has been taken off the market due to safety issues, shortage of raw materials, or low market demand.
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Highlights for methoxsalen

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1

Methoxsalen is used to treat certain skin conditions. These include psoriasis (a condition that causes dry, scaly, itchy skin) and vitiligo (loss of skin color). These conditions also include skin symptoms of a cancer called cutaneous T-cell lymphoma.

2

Methoxsalen is used along with exposure to ultraviolet (UV) light. This light is administered in your doctor’s office.

3

Methoxsalen comes in the form of an oral capsule with two versions: a soft gelatin capsule and a hard gelatin capsule. It’s also available as a lotion and an intravenous (IV) injection. These last two forms are only given by a healthcare provider.

4

Methoxsalen capsules are available as the brand-name drugs Oxsoralen Ultra (soft gelatin capsule) and 8-MOP (hard gelatin capsule). The soft gelatin capsule is also available as a generic drug.

5

The more common side effects of this drug include nausea or skin itching, redness, or tenderness.

IMPORTANT INFORMATION

FDA Warning

This drug has a black box warning. This is the most serious warning from the Food and Drug Administration (FDA). A black box warning alerts doctors and patients about drug effects that may be dangerous.

Requirements of use warning. Methoxsalen should only be prescribed by doctors who have special training and experience in using this drug. Also, for treatment of psoriasis, this drug should only be used under certain conditions. You should only use it if you have a severe, disabling form of psoriasis and you’ve already tried other drugs that haven’t worked.

Oral capsule forms warning. There are two types of methoxsalen oral capsules: a soft gelatin capsule and a hard gelatin capsule. These two capsules are not the same, and you cannot substitute one for the other. You should only take the form that your doctor prescribes for you.

Skin cancer

Methoxsalen raises your risk of certain types of skin cancer. You’re at a greater risk if you have fair skin that burns rather than tans. Your risk is also increased if you’ve ever had treatment with x-rays or coal tar with ultraviolet B (UVB) light. This skin cancer risk continues after you stop using this drug.

Cataracts

If your eyes are not protected during the light treatment, methoxsalen raises your risk of cataracts (damage to the lens of the eye). An ophthalmologist (eye doctor) should check your eyes before you start treatment and every two years afterward. You can protect your eyes by wearing wrap-around sunglasses that absorb ultraviolet A (UVA) light for 24 hours after taking the drug. Be sure to wear the sunglasses when you’re outside or exposed to sunlight through a window.

Sunburn, sun allergy, and skin aging

Methoxsalen makes your skin more sensitive to the sun. This raises your risk of severe sunburns. Be sure to follow your doctor’s instructions for avoiding the sun after treatment. This drug also increases your risk of photosensitivity (sun allergy). In addition, the longer you use this drug, the higher your risk of premature (early) skin aging. These effects are similar to the effects caused by too much exposure to sunlight. 

What is methoxsalen?

Methoxsalen is a prescription drug. It comes in the form of an oral capsule with two versions: a soft gelatin capsule and a hard gelatin capsule. It’s also available as a lotion and an intravenous (IV) injection that are only given by a healthcare provider.

Methoxsalen is available as the brand-name drugs Oxsoralen Ultra (soft gelatin capsule) and 8-MOP (hard gelatin capsule). The soft gelatin capsule is also available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version. 

To work, methoxsalen must be combined with exposure to ultraviolet (UV) light, a part of sunlight. This is done in your doctor’s office. It’s called PUVA therapy, or photochemotherapy.

Why it's used

Methoxsalen is used to treat certain skin diseases. The different types of capsules are used to treat the following conditions:

  • 8-MOP (hard gelatin capsule): This form is used with light therapy to treat: 
    • psoriasis (scaly, dry, itchy patches of skin)
    • vitiligo (loss of skin color)
    • skin symptoms of a cancer called cutaneous T-cell lymphoma
  • Oxsoralen-Ultra and generic (soft gelatin capsule): This form is used with light therapy to treat:
    • psoriasis (scaly, dry, itchy patches of skin)

How it works

Methoxsalen belongs to a class of drugs called psoralens. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Methoxsalen is always used with ultraviolet light (a part of sunlight). Methoxsalen makes your skin more sensitive to light and increases the damage that light does to your skin. If you have psoriasis or cutaneous T-cell lymphoma, this damage stops the cells from growing out of control and making your disease worse. If you have vitiligo, skin cells that make color help repair the damage. This helps restore color to the affected skin. 

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methoxsalen Side Effects

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More Common Side Effects

The more common side effects that can occur with use of methoxsalen include:

  • nausea

  • skin itching

  • redness of the skin

  • skin tenderness

If these effects are mild, they may go away within a couple of days. If they’re more severe or don’t go away after 2 days, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following: 

  • Skin reactions. Symptoms can include:

    • blistering of the skin 
    • skin burns
  • Cataracts. Symptoms can include:

    • blurred vision 
    • trouble seeing at night
    • eye sensitivity to light
    • seeing halos around lights
    • seeing a yellow tint
  • Skin cancer. Symptoms can include:

    • lesions (areas of damaged tissue) that are blue or blue-black
    • lesions or spots with more than one color
    • any mole or spot that changes in color, size, or shape over time
    • white, waxy lumps
    • brown, scaly patches
    • any lesions or spots with irregular borders
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Methoxsalen does not cause drowsiness. 

After methoxsalen treatment with ultraviolet light, you may have mild redness of the skin for 1–2 days. This is a sign that the therapy is working. 

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
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methoxsalen May Interact with Other Medications

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Methoxsalen can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Medications that might interact with this drug

Interactions that increase your risk of side effects
  • Increased side effects from methoxsalen: Taking methoxsalen with certain medications makes your skin more sensitive to light. This raises your risk of severe sunburn, photosensitivity (sun allergy), or skin cancer. Examples of these drugs include:
    • Drugs used for the treatment of an infection or diabetes such as coal tar, griseofulvin, tetracycline antibiotics, hydrochlorothiazide, or sulfa drugs. If you use any of these drugs, talk with your doctor about whether methoxsalen is safe for you. Also, ask if any other drugs you’re taking can increase your risk of light sensitivity.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Methoxsalen warnings
light-sensitive diseases
People with a history of light-sensitive diseases

If you’ve had certain diseases that make your skin more sensitive to light, you should not use this medication. These conditions include lupus erythematosus, porphyria, xeroderma pigmentosum, or albinism.

cancer
People with cancer

Do not use this medication if you have active melanoma or a history of melanoma or invasive squamous cell carcinomas. If you have basal cell carcinoma, your doctor will monitor you closely for any signs that your cancer is getting worse while you take this drug.

aphakia
People with aphakia (absence of the lens of the eye)

Do not use methoxsalen. It raises your risk of retinal damage. 

liver disease
People with liver disease

This medication is broken down by your liver. If your liver doesn’t work well, you may have increased levels of this drug in your body. Your doctor will monitor you closely if you take this drug.

heart disease
People with heart disease

Talk with your doctor about whether this treatment will work for you. They will need to decide if you can stand for long periods of time, or handle the heat stress caused by UVA therapy.

Pregnant women
Pregnant women

Methoxsalen is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should be used only if the potential benefit justifies the potential risk to the fetus. 

breast-feeding
Women who are breast-feeding

Methoxsalen may pass into breast milk and may cause side effects in a child who is breastfed.

Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.

For seniors
For seniors

Talk with your doctor about whether this drug is safe for you. If you have a history of cataracts, heart conditions, kidney or liver problems, or skin cancer, ask about any problems that this drug might cause.

For children
For children

The safety of methoxsalen oral capsules has not been established in children. They should not be used in people younger than 18 years. 

When to call the doctor
When to call the doctor

Call your doctor if:

  • You forget to take your methoxsalen capsules before your scheduled appointment for ultraviolet light treatment.
  • You become pregnant while taking this drug. 
Allergies
Allergies

Methoxsalen can cause a severe allergic reaction. Symptoms can include:

  • trouble breathing
  • swelling of your throat or tongue

If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

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How to Take methoxsalen (Dosage)

Oral capsule

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Severe psoriasis

Generic: methoxsalen

Form: Oral capsule (soft gelatin)
Strengths: 10 mg

Brand: 8-MOP

Form: Oral capsule (hard gelatin)
Strengths: 10 mg

Brand: Oxsoralen-Ultra

Form: Oral capsule (soft gelatin)
Strengths: 10 mg
Adult dosage (ages 18 years and older)

Typical dosage: Your doctor will determine your first dose based on your weight. Your doctor will also decide on the number of treatments you’ll have. You won’t have them more often than every other day.

Child dosage (ages 0–17 years)

It has not been confirmed that methoxsalen oral capsules are safe to use in people younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Vitiligo

Brand: 8-MOP

Form: Oral capsule (hard gelatin)
Strengths: 10 mg
Adult dosage (ages 18 years and older)

Typical dosage: 2 capsules (20 mg). Therapy should occur every other day. You should never have treatment 2 days in a row.

Child dosage (ages 0–17 years)

It has not been confirmed that methoxsalen oral capsules are safe to use in people younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Skin symptoms of cutaneous T-cell lymphoma

Brand: 8-MOP

Form: Oral capsule (hard gelatin)
Strengths: 10 mg
Adult dosage (ages 18 years and older)

Typical dosage: Your doctor will determine your dose and how often you should have treatment.

Child dosage (ages 0–17 years)

It has not been confirmed that methoxsalen oral capsules are safe to use in people younger than 18 years.

Senior dosage (ages 65 years and older)

The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.

Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Clinical Associate Professor, University of Illinois at Chicago College of Pharmacy

Methoxsalen comes with risks if you don’t take it as prescribed.

If you miss doses or don’t take the drug on schedule

If you miss your dose, you won’t be able to have your next ultraviolet light treatment. Without treatment, your condition may not get better, and may get worse.

If you take too much

You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:

  • nausea
  • vomiting
  • serious skin burning or blistering if exposed to sunlight or UV light

If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room right away. You should avoid sunlight and stay in a darkened room for at least 24 hours.

What to do if you miss a dose

If you forget to take methoxsalen before your appointment, call your doctor to find out what you should do.

How to tell if the drug is working

Your skin condition should improve.

Methoxsalen is used for long-term treatment.

Important considerations for taking methoxsalen

Take your methoxsalen capsules before your appointment

Your doctor will tell you when to take the medication. Typically, the best time to take it depends on why you’re taking it: 

  • Psoriasis:
    • Hard capsules: 2 hours before your UV light treatment
    • Soft capsules: 1.5–2 hours before your UV light treatment
  • Vitiligo: 2–4 hours before your light treatment
  • Skin symptoms of cutaneous T-cell lymphoma: Your doctor will decide when you should take your medication.

Store this drug carefully

  • Store methoxsalen capsules at room temperature between 59°F and 86°F (15°C and 30°C).
  • Keep this drug away from light.
  • Don’t store this medication in moist or damp areas, such as bathrooms.

A prescription for this medication is refillable

You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

If you’ll be out of town for your next scheduled light therapy treatment, talk with your doctor to find out what options are available to you while traveling. 

Self-management

Using certain antibacterial or deodorant soaps while taking this drug can make your skin more sensitive to light. This raises your risk of severe sunburn, photosensitivity (sun allergy), or skin cancer. Your doctor can tell you more.

Sun sensitivity

Methoxsalen makes your skin more sensitive to the sun. The UV-treated area is highly sensitive. Exposing that skin to the sun can cause a severe burn. The rest of your body is also more sensitive to the sun. Be sure to take these precautions after you have methoxsalen capsules and light therapy:

  • Wear special wrap-around sunglasses that totally block or absorb ultraviolet light. Regular sunglasses are not enough. Put these special glasses on right after taking methoxsalen. Keep wearing them for 24 hours if you’re in any sunlight, even if it’s coming through a window.
  • Protect your skin and lips from sunlight for at least 8 hours after each treatment. Wear protective clothing (such as a hat or gloves) to cover as much of your body as possible. Use sunscreen with an SPF of 15 or higher.
  • Do not sunbathe for 48 hours (2 days) after a treatment.
  • Avoid sunlight for 24 hours before each treatment.

Insurance

Many insurance companies require a prior authorization for this drug. This means your doctor may need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

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How Much Does methoxsalen Cost?

Oral capsule

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Lowest price for methoxsalen

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These prices represent the lowest priced national pharmacies for methoxsalen on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on January 6, 2016

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
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