[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Other dermatological medicines](https://durgical.com/en/pharmacology/classes/other-dermatological-medicines/) › Methoxsalen

# Methoxsalen

## Other dermatological medicines?

Other dermatological medicines

A psoralen that makes skin sensitive to ultraviolet A light; with UVA (PUVA) it treats severe psoriasis and vitiligo, and it is used in photopheresis.

Updated Nov 1, 2026

Also called: 8-methoxypsoralen

## Quick facts

**Group**
[Other dermatological medicines](https://durgical.com/en/pharmacology/classes/other-dermatological-medicines/)

**Target**
DNA of skin cells, after activation by ultraviolet A light

**Used for**
Severe · Vitiligo · Cutaneous T-cell lymphoma

**Key effects**
Nausea · Itching · Expected redness after treatment

**Monitor**
Skin redness · Eye examinations for cataracts

**ATC**
D05BA02

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Methoxsalen is a psoralen, a plant-derived furocoumarin. It slips between DNA bases, and when long-wave ultraviolet A light reaches the skin it forms covalent bonds and crosslinks with DNA and generates reactive oxygen species. This slows the overgrowth of psoriatic skin cells, suppresses skin immune cells and stimulates melanocytes.

- Methoxsalen enters skin cells and slips into DNA
- UVA light activates it
- It crosslinks DNA and forms reactive oxygen species
- Cell overgrowth slows; melanocytes are stimulated

## Indications

- Severe, disabling psoriasis not controlled by other treatments (PUVA) [Psoriasis →](https://durgical.com/en/conditions/psoriasis/)
- Vitiligo (PUVA) [Vitiligo →](https://durgical.com/en/conditions/vitiligo/)
- Cutaneous T-cell lymphoma (extracorporeal photopheresis) [Mycosis fungoides and Sézary syndrome (cutaneous T-cell lymphoma) →](https://durgical.com/en/conditions/mycosis-fungoides-and-sezary-syndrome/)

## Adverse effects

### Common

- Nausea
- Itching
- Expected redness after treatment; burns if overexposed
- Dizziness, headache, nervousness, insomnia

### Serious (rare, important)

- Severe phototoxic burns
- Cataracts if the eyes are not protected
- Skin cancer, including squamous cell carcinoma and melanoma, with cumulative treatment
- Premature skin aging

## Contraindications

- Idiosyncratic reaction to psoralens
- Light-sensitive diseases (lupus, porphyrias, xeroderma pigmentosum, albinism)
- Melanoma or a history of melanoma; invasive squamous cell carcinoma
- Aphakia (no lens in the eye)

## Key interactions

**Other photosensitising drugs (tetracyclines, fluoroquinolones, thiazides, sulfonamides, phenothiazines, griseofulvin, coal tar)**
Greater risk of severe burns.

## What is monitored

- Skin redness and burns after each session
- Eye examinations for cataracts
- Lifelong skin checks for cancer, including melanoma
- Liver function where impaired

## Administration and safety

- Given only by clinicians trained in photochemotherapy, under close supervision.
- Oral formulations differ in absorption and onset, so one is not swapped for another without the team.
- Total UVA-blocking goggles during treatment and wrap-around UVA-absorbing sunglasses for 24 hours afterwards.

## Pregnancy and breastfeeding

Animal reproduction studies have not been done and fetal risk is unknown; it is used in pregnancy only if clearly needed.

## Nursing care

- Review the medicine list for other photosensitising drugs before each course.
- Confirm eye protection during and after each session.
- Inspect the skin for burns and teach to report blistering or severe redness.
- Remind about lifelong skin cancer checks.

## Pharmacokinetics

**Absorption**
Oral; absorption and onset differ between formulations, and fatty food slows absorption

**Metabolism**
Liver, with a large first-pass effect

**Half-life**
About one hour, but the skin stays sensitive to light for many hours

## Memory aid

PUVA = Psoralen + UVA: Protect the eyes, Unwanted burns, Very long cancer watch, Avoid other photosensitisers.

## Test yourself

Think of the answer, then tap the question to see it.

## What does methoxsalen need to work?

Ultraviolet A light (PUVA): the light activates it to crosslink DNA.

## Why must patients wear UVA-blocking eye protection after methoxsalen?

To prevent cataracts.

## Which long-term skin risks follow repeated PUVA?

Squamous cell carcinoma, melanoma and premature skin aging.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/methoxsalen/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 2

- [Acitretin](https://durgical.com/en/pharmacology/acitretin/)
- [Calcipotriol](https://durgical.com/en/pharmacology/calcipotriol/)

## Related conditions 3

- [Psoriasis](https://durgical.com/en/conditions/psoriasis/)
- [Vitiligo](https://durgical.com/en/conditions/vitiligo/)
- [Mycosis fungoides and Sézary syndrome (cutaneous T-cell lymphoma)](https://durgical.com/en/conditions/mycosis-fungoides-and-sezary-syndrome/)

[← Back to the class: Other dermatological medicines](https://durgical.com/en/pharmacology/classes/other-dermatological-medicines/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - METHOXSALEN capsule, liquid filled](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a6ec8292-9189-4ebd-862a-e1725eb29eef) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=D05BA02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/methoxsalen/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/methoxsalen/