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8-MOP Side Effects

Generic Name: methoxsalen

Note: This page contains information about the side effects of methoxsalen. Some of the dosage forms included on this document may not apply to the brand name 8-MOP.

For the Consumer

Applies to methoxsalen: oral capsule, oral capsule liquid filled

In addition to its needed effects, some unwanted effects may be caused by methoxsalen (the active ingredient contained in 8-MOP). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking methoxsalen:

  • Blistering and peeling of skin
  • reddened, sore skin
  • swelling (especially of feet or lower legs)

Minor Side Effects

Some of the side effects that can occur with methoxsalen may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Itching of skin
  • nausea
Less common:
  • Dizziness
  • headache
  • mental depression
  • nervousness
  • trouble in sleeping

Treatment with this medicine usually causes a slight reddening of your skin 24 to 48 hours after the treatment. This is an expected effect and is no cause for concern. However, check with your doctor right away if your skin becomes sore and red or blistered.

There is an increased risk of developing skin cancer after use of methoxsalen. You should check 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 what happens when a person sunbathes for long periods of time.

For Healthcare Professionals

Applies to methoxsalen: compounding powder, injectable solution, oral capsule


Dermatologic side effects have included mild to serious skin burns, premature aging of the skin, pruritus, inflammation, erythema, rash (nonspecific), edema, extension of psoriasis, cutaneous tenderness, hypopigmentation, keratosis, folliculitis, dermal vessel damage, longer duration of epidermal and dermal abnormalities, miliaria, urticaria, vesiculation formation, and bullae formation. Postmarketing dermatologic side effects have included rash.[Ref]


Cardiovascular side effects are mostly associated with methoxsalen (the active ingredient contained in 8-MOP) sterile solution and have included arrhythmia and serious (nonspecific) cardiovascular adverse experiences. Hypotension and dizziness have been associated with the sterile solution and the oral administration of methoxsalen.[Ref]


Immunologic side effects associated with the sterile solution have included infections (nonspecific) and hickman catheter infections. Immunologic side effect with oral administration of methoxsalen (the active ingredient contained in 8-MOP) has been herpes simplex.[Ref]


Oncologic side effects have included cutaneous squamous cell cancers, malignant melanoma, and basal cell carcinoma.[Ref]


Psychiatric side effects have included depression.[Ref]


Gastrointestinal side effects have included unspecified gastrointestinal disturbances. Postmarketing gastrointestinal side effects have included nausea and dysgeusia.[Ref]


General side effects have included malaise and headache. Postmarketing general side effects have included pyrexia.[Ref]


Ocular side effects have included cataracts.[Ref]


Hypersensitivity side effects have included postmarketing reports of allergic reaction.[Ref]


1. "Product Information. Oxsoralen (methoxsalen)." ICN Pharmaceuticals Inc, Costa Mesa, CA.

2. "Product Information. Uvadex (methoxsalen)." Therakos Inc, Exton, PA.

Not all side effects for 8-MOP may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.