Some medicines can make the skin more sensitive to sunlight. This occurs when sunlight (which has ultraviolet, or UV, light) interacts with small concentrations of medicines that are in the skin. Some medicines, such as antibiotics, antidepressants, anti-seizure drugs and anti-hypertensives, as well as some herbs, such as St. John's wort (and its extracts, hypericin and hyperforin), have this effect.
In general, two patterns of skin sensitivity can occur when the skin is exposed to UV light, as follows:
Laboratory experiments suggested that TMC435 (simeprevir) had the potential to be a photosensitizing agent. To explore the potential for this problem, researchers recruited otherwise-healthy volunteers and then randomly assigned them to receive one of the following interventions for nine days:
Cipro was chosen because it is a mild sun sensitizer.
Artificial UV light similar to mid-summer sunlight was given to participants to simulate sun exposure just before and immediately after they stopped taking the study drugs.
Researchers recruited 36 participants (all were White), 33 men and 3 women, and assigned 12 people to receive each intervention.
Eleven volunteers developed mild, moderate or severe photosensitivity; three of these were taking placebo. Three cases of mild photosensitivity occurred among simeprevir users.
No statistically significant differences in the intensity of skin reactions among the different interventions were noted.
No changes in commonly assessed lab tests were seen during the study period.
The research team concluded that simeprevir is not associated with an increased risk of sun sensitivity.
Simion A, Janssens L, Peeters M, et al. Absence of photosensitivity potential of TMC435 in healthy volunteers. Abstract 1159. In: Program and abstracts of the 47th annual meeting of the European Association for the Study of the Liver, 18-22 April 2012, Barcelona, Spain.
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