8-MOP

8-MOP Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

8-MOP (methoxsalen) is used in combination with UVA light therapy to treat severe psoriasis. It is a naturally occurring substance that is reactive to light. Common side effects include nausea or trouble sleeping. Mild itching/drying/reddening/darkening of skin may occur when this drug is used along with UVA light treatment.

Dosing of 8-MOP is based on the patient's weight. The capsules should be taken 2 hours before UVA exposure with some food or milk. 8-MOP may interact with arsenic trioxide, anthralin, bacteriostatic soaps, coal tar, griseofulvin, nalidixic acid, staining dyes, sulfa drugs, diuretics (water pills), antibiotics, or medicines to treat psychiatric disorders. Tell your doctor all medications and supplements you use, including those applied to the skin. 8-MOP is not recommended for use during pregnancy. It may harm a fetus. It is unknown if this medication passes into breast milk. Because of the possible risk to the infant, breastfeeding while using this drug is not recommended.

Our 8-MOP (methoxsalen) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is Patient Information in Detail?

Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.

8-MOP in Detail - Patient Information: Side Effects

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 severe skin discomfort;
  • blisters, pimples, or skin rash;
  • blurred vision, eye pain, or seeing "halos" around lights;
  • feeling like you might pass out; or
  • worsening of your psoriasis.

Less serious side effects may include:

  • mild skin redness, itching, or tenderness;
  • nausea;
  • depressed mood;
  • feeling nervous;
  • sleep problems (insomnia);
  • cold sores;
  • headache, dizziness; or
  • leg pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for 8-MOP (Methoxypsoralen) »

What is Prescribing information?

The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.

8-MOP FDA Prescribing Information: Side Effects
(Adverse Reactions)

SIDE EFFECTS

Methoxsalen

The most commonly reported side effect of methoxsalen alone is nausea, which occurs with approximately 10% of all patients. This effect may be minimized or avoided by instructing the patient to take methoxsalen with milk or food, or to divide the dose into two portions, taken approximately one-half hour apart. Other effects include nervousness, insomnia, and psychological depression.

Combined methoxsalen/uva therapy

  1. Pruritus: This adverse reaction occurs with approximately 10% of all patients. In most cases, pruritus can be alleviated with frequent application of bland emollients or other topical agents; severe pruritus may require systemic treatment. If pruritus is unresponsive to these measures, shield pruritic areas from further UVA exposure until the condition resolves. If intractable pruritus is generalized, UVA treatment should be discontinued until the pruritus disappears.
  2. Erythema: Mild, transient erythema at 24-48 hours after PUVA therapy is an expected reaction and indicates that a therapeutic interaction between methoxsalen and UVA occurred. Any area showing moderate erythema (greater than Grade 2 - see Table 1 for grades of erythema) should be shielded during subsequent UVA exposures until the erythema has resolved. Erythema greater than Grade 2 which appears within 24 hours after UVA treatment may signal a potentially severe burn. Erythema may become progressively worse over the next 24 hours, since the peak erythemal reaction characteristically occurs 48 hours or later after methoxsalen ingestion. The patient should be protected from further UVA exposures and sunlight, and should be monitored closely.
  3. Important Differences Between Puva Erythema And Sunburn: PUVA-induced inflammation differs from sunburn or UVB phototherapy in several ways. The in situ depth of photochemistry is deeper within the tissue because UVA is transmitted further into the skin. The DNA lesions induced by PUVA are very different from UV-induced thymine dimers and may lead to a DNA crosslink. This DNA lesion may be more problematic to the cell because crosslinks are more lethal and psoralen-DNA photoproducts may be “new” or unfamiliar substrates for DNA repair enzymes. DNA synthesis is also suppressed longer after PUVA. The time course of delayed erythema is different with PUVA and may not involve the usual mediators seen in sunburn. PUVA-induced redness may be just beginning at 24 hours, when UVB erythema has already passed its peak. The erythema dose-response curve is also steeper for PUVA. Compared to equally erythemogenic doses of UVB, the histologic alterations induced by PUVA show more dermal vessel damage and longer duration of epidermal and dermal abnormalities.
  4. Other Adverse Reactions: Those reported include edema, dizziness, headache, malaise, depression, hypopigmentation, vesiculation and bullae formation, non-specific rash, herpes simplex, miliaria, urticaria, folliculitis, gastrointestinal disturbances, cutaneous tenderness, leg cramps, hypotension, and extension of psoriasis.

Read the entire FDA prescribing information for 8-MOP (Methoxypsoralen) »

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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.


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