What is Methoxsalen used for?
Methoxsalen is used along with controlled ultraviolet light (UVA) to help control severe psoriasis. Methoxsalen works by making the skin more sensitive to UVA light. This combination helps to slow the overgrowth of skin cells.
This medication is not recommended for use in children younger than 12 years.
How should I take Methoxsalen?
Do not sunbathe for 24 hours before taking methoxsalen and having the UVA light treatment.
Take this medication by mouth with low fat food or milk, usually 90 minutes to 2 hours before your UVA light treatment or as directed by your doctor. Taking methoxsalen with food helps to increase absorption of the medication and also decreases nausea.
The dosage of methoxsalen is based on your weight, medical condition, and response to treatment. The amount and time of UVA light for each treatment is based on your skin type and response to treatment. You may have UVA light treatments 2 to 4 times a week when you first start and then less frequently as your condition improves.
For 24 hours after taking the capsule, during daylight hours wear wrap-around sunglasses which block out UVA light. This will prevent UVA rays from entering the eyes. UVA light can cause methoxsalen to bind to the lenses of the eyes, causing cataracts. Also, avoid sunlight (including sunlight through windows) on your skin or lips for at least 8 hours after taking methoxsalen. This will prevent the body from getting too much UVA rays which could lead to sunburns. If you cannot avoid sunlight, wear protective clothing (such as hat, gloves, long-sleeved shirt, pants) and/or sunscreen which blocks out UVA light. Consult your doctor or pharmacist for information on which sunscreen to use. Do not apply the sunscreen to areas of the skin affected by psoriasis until after the UVA light treatment.
During the UVA light treatment, follow all instructions given by the healthcare professional. After the UVA light treatment, do not sunbathe for at least 48 hours. Doing so may increase the risk of severe burns. Consult your doctor for more details.
Tell your doctor if your condition does not improve or if it worsens.
How do I store Methoxsalen?
Methoxsalen is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Methoxsalen in the bathroom or the freezer. There may be different brands of Methoxsalen that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.
You should not flush Methoxsalen down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.
Precautions & warnings
What should I know before using Methoxsalen?
Before taking methoxsalen, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: conditions that make you sensitive to light (such as lupus, certain porphyrias, xeroderma pigmentosum, albinism), skin cancer (melanoma, basal cell or squamous cell carcinomas), removal of natural lens in the eye, coal tar/UVB treatment, radiation treatment, arsenic treatment, cataracts, liver disease, heart disease, kidney disease.
Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
This medication is not recommended for use during pregnancy. It may harm an unborn baby. Consult your doctor for more details.
It is unknown if this medication passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.
Is it safe during pregnancy or breast-feeding?
There are no adequate studies in women for determining risk when using this Methoxsalen during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Methoxsalen. Methoxsalen is pregnancy risk category D according to the US Food and Drug Administration (FDA).
FDA pregnancy risk category reference below:
- A=No risk,
- B=No risk in some studies,
- C=There may be some risk,
- D=Positive evidence of risk,
What side effects can occur from Methoxsalen?
Nausea or trouble sleeping may occur with methoxsalen. Mild itching/drying/reddening/darkening of skin may occur when methoxsalen is used along with UVA light treatment. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
If needed, consult your doctor or pharmacist about which products (such as a moisturizer) to use to help treat dry/itchy skin.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if any of these unlikely but serious side effects occur: severe reddening of skin, blistering/peeling/burning of skin, thinning/wrinkling skin, painful browning/whitening/yellowing of nails, swelling ankles, mental/mood changes (such as depression, nervousness).
Tell your doctor right away if any of these rare but seriousunusual growths/moles/skin sores, decreased/blurred vision.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.
What drugs may interact with Methoxsalen?
Some products that may interact with this drug include: other medications that may make your skin sensitive to light (such as anthralin, coal tar, griseofulvin, sulfa antibiotics including sulfamethoxazole, fluoroquinolone antibiotics including ciprofloxacin, thiazide diuretics including hydrochlorothiazide, tetracycline antibiotics including doxycycline).
Methoxsalen may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.
Does food or alcohol interact with Methoxsalen?
Methoxsalen may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.
What health conditions may interact with Methoxsalen?
Methoxsalen may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.
The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Methoxsalen.
What is the dose of Methoxsalen for an adult?
Usual Adult Dose for Psoriasis
Initial dose: Based on patient weight.
<30 kg = 10 mg
30 to 50 kg = 20 mg
51 to 65 kg = 30 mg
66 to 80 kg = 40 mg
81 to 90 kg = 50 mg
91 to 115 kg = 60 mg
>115 kg = 70 mg
The initial UVA exposures are based on the patient’s skin type and should be conducted according to the guidelines in professional literature.
Maintenance dose: Dose, schedule, and UVA exposure are based on the patients skin type, grades of erythema, and response to therapy per guidelines in professional literature.
Usual Adult Dose for Cutaneous T-cell Lymphoma
Summary of UVAR photopheresis system (see the UVAR photopheresis system operator’s manual for details of this process):
The UVAR system removes a portion of the patient’s blood and separates the red blood cells from the white cell layer (buffy coat) by centrifugation. The red cells are returned to the patient and the methoxsalen sterile solution is then injected into the UVAR system and mixed with the buffy coat. The UVAR system then irradiates this drug-cell mixture with ultraviolet light (UVA light, 320 to 400 nm) and returns the treated cells to the patient.
Initial dose: 10 mL (200 mcg) of methoxsalen sterile solution is injected directly into the photoactivation bag during the first buffy coat collection cycle.
Maintenance: Treatment is given on two consecutive days every four weeks.
Duration: Minimum of seven treatment cycles (six months).
If assessment of the patient during the fourth treatment cycle (approximately 3 months) of the UVAR photopheresis system reveals an increased skin score from the baseline score, the frequency of treatment may be increased to two consecutive treatments every two weeks for a maximum of 20 cycles.
Suitable covering or a topical sunblock (SPF 15 or higher) should follow the therapeutic UVA exposure along with wraparound UVA-absorbing sunglasses for the 24 hour period following treatment with methoxsalen, whether exposed to direct or indirect sunlight in the open or through a window glass.
Patients should not sunbathe for 48 hours after therapy.
Methoxsalen soft-gelatin capsules should not be used interchangeably with regular hard-gelatin capsules. The methoxsalen soft-gelatin capsules exhibit significantly greater bioavailability and earlier photosensitization onset time then hard-gelatin capsules.
The blistering of the skin sometimes encountered after UVA exposure generally heals without complication or scarring.
Patients should have an ophthalmologic examination and routine laboratory tests prior to the start of therapy.
There is no clinical evidence to show that treatment with methoxsalen sterile solution beyond six months or using a different schedule provides additional benefit.
Methoxsalen capsules should be taken 1.5 to 2 hours before UVA exposure with some low fat food or milk.
What is the dose of Methoxsalen for a child?
The dosage has not been established in pediatric patients. It may be unsafe for your child. It is always important to fully understand the safety of the drug before using. Please consult with your doctor or pharmacist for more information.
How is Methoxsalen available?
Methoxsalen is available in the following dosage forms and strengths:
- Oral capsule,
- Compounding powder,
- Injectable solution.
What should I do in case of an emergency or overdose?
In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.
What should I do if I miss a dose?
If you miss a dose of Methoxsalen, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: March 23, 2018 | Last Modified: September 12, 2019
Methoxsalen Dosage. https://www.drugs.com/dosage/methoxsalen.html. Accessed March 15, 2018.
Methoxsalen. https://www.webmd.com/drugs/2/drug-6957-1257/methoxsalen-oral/methoxsalen-rapid-oral/details. Accessed March 15, 2018.