Photosensitizing drugs are substances that increase the skin's sensitivity to ultraviolet (UV) radiation from the sun or artificial light sources. This increased sensitivity can lead to faster skin burning, rashes, or other reactions, even after only brief exposure to sunlight. The reaction, often referred to as a phototoxic or photoallergic reaction, depends on the type of drug and individual sensitivity.
mechanism
- Phototoxic reactions occur when the drug, after absorbing light energy, becomes a toxic product that directly damages skin cells. This can lead to a reaction similar to a severe sunburn, often within hours of sun exposure.
- Photoallergic reactions are less common and occur when UV radiation converts the medication into an antigen that triggers an allergic reaction of the immune system. This reaction can be delayed and is more similar to eczema.
Examples of photosensitizing drugs
Medications and substances that can cause photosensitivity include:
- Certain antibiotics : such as tetracyclines and fluoroquinolones
- Nonsteroidal anti-inflammatory drugs (NSAIDs) : such as ibuprofen and naproxen
- Diuretics : Such as hydrochlorothiazide
- Antipsychotics : Such as phenothiazines
- Antifungal agents : such as voriconazole
- Retinoids : Both oral for acne and topical
- Heart medications : How amiodarone
- Chemotherapeutic agents
Management and prevention
To prevent photosensitizing reactions, people taking such medications should take the following precautions:
- Minimize sun exposure : Avoid direct sunlight, especially between 10 a.m. and 4 p.m. when UV radiation is strongest.
- Wear protective clothing : Long sleeves, trousers and wide-brimmed hats offer physical protection from UV rays.
- Use broad-spectrum sunscreen : A sunscreen with a high sun protection factor (SPF 30 or higher) that blocks both UVA and UVB rays should be applied regularly.
- Avoid sunbeds : Artificial UV sources can cause similar reactions.
Important to note
Not everyone taking a photosensitizing medication will experience a skin reaction. Sensitivity can vary from person to person. If a skin reaction occurs, it is advisable to consult a doctor. The medication may need to be adjusted or replaced with an alternative. Always follow the advice of a healthcare provider and be sure to inform them about potential side effects of any new medication.
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