What is Methoxsalen?

Methoxsalen is a naturally occurring substance that is reactive to light. It works by enhancing the body’s sensitivity to ultraviolet light A (UVA).
Methoxsalen is used in combination with UVA light therapy to treat severe psoriasis.
Methoxsalen may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about Methoxsalen?

You should not use this medication if you are allergic to methoxsalen, or if you have a history of skin cancer or damage to the lenses of your eyes due to surgery, injury, or genetic condition.
Before taking methoxsalen, tell your doctor if you have lupus, porphyria, heart disease, kidney or liver disease, a history of cataracts, a skin pigment disorder, if you are extremely sensitive to sunlight, or if you have recently gained or lost weight.
There are many other drugs that can interact with methoxsalen, including drugs applied to the skin. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.
After taking methoxsalen and receiving UVA treatment, you must protect your eyes and skin from natural sunlight (even sun shining through a window).
Wear wraparound UVA-absorbing sunglasses for at least 24 hours after your light treatment, even while you are indoors near a window.
You may develop cataracts if you do not properly protect your eyes after you are treated with methoxsalen and UVA treatment.
Use a sunscreen with a minimum SPF of 15, and wear protective clothing including a hat and gloves for at least 8 hours after your light treatment.
Follow your doctor’s instructions about applying topical psoriasis medications or any moisturizing lotions after your methoxsalen and UVA treatment.

What should I discuss with my healthcare provider before taking Methoxsalen?

You should not use this medication if you are allergic to methoxsalen, or if you have:

• a history of skin cancer; or
• damage to the lenses of your eyes due to surgery, injury, or genetic condition

If you have certain conditions, you may need a dose adjustment or special tests to safely use this medication. Before using methoxsalen, tell your doctor if you have:

• heart disease
• kidney disease
• liver disease
  

  systemic lupus erythematosus

• porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system)
• a history of cataracts
• a skin pigment disorder
• if you are extremely sensitive to sunlight; or
• if you have recently gained or lost weight

FDA pregnancy category C. Methoxsalen may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
It is not known whether methoxsalen passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Methoxsalen Side Effects

What are the possible side effects of Methoxsalen?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Methoxsalen is expected to produce skin redness that may not occur until several hours after your UVA treatment. This redness may last for 2 or 3 days. You may also have slight swelling. These are normal effects of the medication and UVA treatment.
Call your doctor at once if you have a serious side effect such as:

• severe skin redness within 24 hours after UVA treatment
• severe itching, swelling, or skin discomfort
• blisters, pimples, or skin rash
• feeling like you might pass out; or
• worsening of your psoriasis

Less serious side effects may include:

• nausea, upset stomach
• headache, dizziness
• depressed mood
• sleep problems (insomnia)
• feeling nervous
• leg pain; or

• mild skin itching or tenderness

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Methoxsalen Interactions

What other drugs affect Methoxsalen?

Tell your doctor about all medications you use now or have used in the past (including those applied to the skin), especially:

• arsenic trioxide (Trisenox)
• anthralin (Drithrocreme, Micanol)
• a bacteriostatic soap
• coal tar (Betatar Gel, Denorex, Fototar, Ionil T, MG217, Neutrogena T/Gel or T/Derm, Tegrin Medicated Soap, and others)
• griseofulvin (Fulvicin, Grisactin)
• nalidixic acid (NegGram)
• a staining dye such as methylene blue, toluene blue, rose bengal, or methyl orange
• a sulfa drug (Bactrim, Gantanol, Septra, and others)
• a diuretic (water pill) such as chlorothiazide (Diuril), hydrochlorothiazide (HCTZ, HydroDiuril, Hyzaar, Lopressor, Vasoretic, Zestoretic), chlorthalidone (Hygroton, Thalitone), indapamide (Lozol), metolazone (Mykrox, Zaroxolyn), and others
• an antibiotic such as ciprofloxacin (Cipro), ofloxacin (Floxin), norfloxacin (Noroxin), levofloxacin (Levaquin), lomefloxacin (Maxaquin), and others
• a tetracycline antibiotic such as demeclocycline (Declomycin), doxycycline (Adoxa, Doryx, Oracea, Vibramycin), minocycline (Dynacin, Minocin, Solodyn, Vectrin), or tetracycline (Brodspec, Panmycin, Sumycin, Tetracap); or
• medicine to treat a psychiatric disorder, such as chlorpromazine (Thorazine), fluphenazine (Prolixin), mesoridazine (Serentil), perphenazine (Trilafon), prochlorperazine (Compazine), thioridazine (Mellaril), or trifluperazine (Stelazine)

This list is not complete and there may be other drugs that can interact with methoxsalen. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

What should I avoid while taking Methoxsalen?

Methoxsalen will make your skin more sensitive to sunlight and sunburn may result. Even sunlight shining through a glass window can expose you to harmful UV rays. Avoid exposure to sunlight or artificial UV rays other than your scheduled light therapy treatments.
Before your UVA treatment: Do not expose your skin to sunlight for at least 24 hours before you take methoxsalen. Avoid applying sunscreen to areas of psoriasis that will be treated with UVA therapy.
After your UVA treatment: Do not expose your skin to sunlight for at least 8 hours after your UVA treatment. Wear protective clothing including a hat and gloves. Use a sunscreen with a minimum SPF of 15, and apply it to all uncovered skin areas exposed to light.


Methoxsalen Dosage

How should I take Methoxsalen?

Take this medication exactly as prescribed by your doctor. Do not take methoxsalen in larger amounts or for longer than recommended. Follow the directions on your prescription label. Taking too much methoxsalen can cause your skin to be overly sensitive to light, and severe sunburn may result.
Methoxsalen is usually taken 90 minutes to 2 hours before you are scheduled to receive UVA treatment. The timing of your medication may depend on whether you are taking the soft gelatin capsule or the hard gelatin capsule.
The methoxsalen soft gelatin capsule is more easily absorbed in the body than the hard gelatin capsule. For this reason, you may be sensitive to UVA treatment more quickly after taking the soft gelatin capsule.
Take this medication with low-fat food or milk if it upsets your stomach.
After taking methoxsalen and receiving UVA treatment, you must protect your eyes from natural sunlight (even sun shining through a window). Wear sunglasses for at least 24 hours after treatment. For utmost protection, wear a pair of wraparound UVA-absorbing sunglasses, even while you are indoors near a window.
You may develop cataracts if you do not properly protect your eyes after you are treated with methoxsalen and UVA treatment.
Follow your doctor’s instructions about applying topical psoriasis medications or any moisturizing lotions after your methoxsalen and UVA treatment.
While taking methoxsalen, check your skin regularly for signs of skin cancer, such as a small growth or nodule, a scaly or crusted lesion, a brownish spot or speckles, or a change in the size, color, or feel of a mole. After receiving UVA treatments, you may need to check your skin for signs of cancer throughout the rest of your life.
If you store methoxsalen at home, keep it at room temperature away from moisture and heat.

What happens if I overdose on Methoxsalen?

Stay in a dark room and call your doctor at once if you think you have used too much of this medicine. You will be extremely sensitive to light after an overdose, and you may need to seek emergency medical attention.
Overdose symptoms may include nausea, dizziness, or fainting.

What happens if I miss a dose of Methoxsalen?

Call your doctor for instructions if you miss your methoxsalen dose or forget to take the medicine within 90 minutes to 2 hours before your scheduled UVA treatment.
The timing of when you take methoxsalen is critical in relation to UVA treatment. Therefore, you may need to reschedule your light therapy appointment if you have not taken methoxsalen at the proper time beforehand.
Edited from everydayhealth.com