methoxsalen (8-MOP, Oxsoralen Ultra)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

View the Adult Skin Problems Slideshow Pictures

What is methoxsalen-oral, and how does it work (mechanism of action)?

  • Methoxsalen is a naturally occurring photoactive chemical found in the seeds of the Ammi majus (Umbelliferae) plant and in the roots of Heraclem candicans. It belongs to a group of compounds known as psoralens, or furocoumarins. It is used for treating psoriasis, idiopathic vitiligo (leucoderma) and cutaneous (skin) manifestations of T-cell lymphoma. The exact mechanism of action of methoxsalen is not known.
  • Methoxsalen has several biological actions that may be responsible for its medical effects. Ultraviolet radiation of 320-400 nm wavelength (UVA) is beneficial for treating psoriasis, vitiligo, and skin manifestations of T-cell lymphoma. Methoxsalen is a photosensitizer that increases the reaction of the skin to UVA. Methoxsalen also combines with DNA in skin cells. Upon administration, methoxsalen reaches the skin via blood. When UVA penetrates the skin, cellular damage occurs, leading to inflammation. The damaged skin heals after several days to weeks.
  • Some experts suggest that methoxsalen improves vitiligo by stimulating melanocytes (melanin forming skin cells) to move up the hair follicle and to repopulate the epidermis. Psoriasis causes an over production of skin cells. Methoxsalen may benefit psoriasis by decreasing skin cell production by damaging DNA.
  • The FDA approved methoxsalen capsules in December 1954.

What brand names are available for methoxsalen-oral?

8-MOP, Oxsoralen Ultra

Is methoxsalen-oral available as a generic drug?

GENERIC AVAILABLE: Yes

Do I need a prescription for methoxsalen-oral?

Yes

What are the uses for methoxsalen-oral?

  • Oral methoxsalen combined with UVA (ultraviolet A) radiation is used as photochemotherapy for the treatment of severe, disabling psoriasis that is difficult to treat and is unresponsive to other treatments.
  • It also is used for treating idiopathic vitiligo (leucoderma) and cutaneous (skin) manifestations of T-cell lymphoma.

What are the side effects of methoxsalen-oral?

Common side effects include:

Other side effects include:

Possible serious side effects include:

Quick GuideRingworm: Treatment, Pictures, Causes, and Symptoms

Ringworm: Treatment, Pictures, Causes, and Symptoms

What is the dosage for methoxsalen-oral?

  • Patients must not sunbathe 24 hours before methoxsalen administration and UV exposure because a sunburn may prevent an accurate evaluation of the response to treatment.
  • UVA-absorbing wrap-around sunglasses designed to prevent entry of radiation to the eyes should be worn during the day for 24 hours after methoxsalen administration.
  • Patients must avoid sun exposure, including through-the window or through cloud cover, for at least 8 hours after methoxsalen administration. Hat and gloves, and/or sunscreens with SPF equal to or greater than 15 should be used if sun exposure cannot be avoided. Sunscreens should be applied to all areas of the body exposed to the sun (including lips). However, sunscreens should not be applied to areas affected by psoriasis until after treatment in the UVA chamber.

Psoriasis

  • The recommended oral dose for treating psoriasis is 10 to 70 mg every other day with milk or food 2 hours before UVA exposure. The dose is based on weight.

Cutaneous T-Cell Lymphoma

  • The recommended initial oral dose for treating cutaneous T-Cell lymphoma is 0.6 mg/kg. Ann additional 10 mg should be taken if the blood concentration of methoxsalen is less than 50 ng/ml.

Vitiligo

  • The recommended oral dose for treating vitiligo is 20 mg every other day with milk or food 2 to 4 hr before UVA exposure. The dose must not exceed 0.6 mg/kg since larger doses may result in serious skin burns.

Which drugs or supplements interact with methoxsalen-oral?

Is methoxsalen-oral safe to take if I'm pregnant or breastfeeding?

  • Methoxsalen has not been adequately studied in pregnant women. Animal data suggest that methoxsalen can harm the fetus when used by a pregnant woman. Women of childbearing potential should be advised to avoid becoming pregnant.
  • It is not known whether methoxsalen is excreted in human milk.

What else should I know about methoxsalen-oral?

What preparations of methoxsalen-oral are available?

Capsule: 10 mg

How should I keep methoxsalen-oral stored?

Methoxsalen should be stored at 15 C to 30 C (59 F to 86 F)

REFERENCE: FDA Prescribing Information

Quick GuideRingworm: Treatment, Pictures, Causes, and Symptoms

Ringworm: Treatment, Pictures, Causes, and Symptoms

Subscribe to MedicineNet's Skin Care & Conditions Newsletter

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Reviewed on 6/23/2016
References
REFERENCE: FDA Prescribing Information

Health Solutions From Our Sponsors