Drugs and lasers/IPLs.

Abstract

We read with interest the recent paper published by Kerstein et al. on laser therapy and photosensitive medication [1]. We welcome the review of the evidence which these authors presented. However, we feel it is important to correct what appears to be a misinterpretation of the 2009 guidelines from the British Medical Laser Association (BMLA) [2]. These guidelines were produced in response to a need to provide advice as some clinics had very long lists extending to two or three pages of drugs which were considered to be contraindications to laser treatment. The guidelines state “phototoxicity generally results from exposure to UVA (315–400 nm) radiation with some drugs showing sensitivity into the visible region of the spectrum up to about 460 nm. For laser/IPL devices emitting wavelengths above 500 nm there is very little likelihood of such a reaction for the vast majority of drugs”. We were therefore surprised to learn that many laser centres, including that of Kerstein et al. [1], were declining to treat patients who were on any medication with a known photosensitivity. This is not at all in accord with the BMLA guidelines. The only drugs which are listed as contraindications are those which are administered for photodynamic therapy (PDT). There is another category of drugs which is not listed as a contraindication but which may cause photosensitivity. The guidelines advocate that treatment in these cases should be performed with caution. These include amiodarone (risk of hyperpigmentation and photosensitivity), minocycline (risk of hyperpigmentation) and St John’s wort (risk of photosensitivity). Amiodarone is a cardiac antidysrhythmic with a wide range of phototoxic effects with sensitivity in the visible region [3, 4]. Minocycline has been shown to induce post-inflammatory hyperpigmentation [5] and St John’s wort has an absorption spectrum that extends well into the visible spectrum [6]. For those taking other medications or herbal remedies, then careful test patching is encouraged. If a client starts a BNF-named photosensitiser during the course of treatment, then it is recommended that a repeat test patch is performed. The third category of drugs is that which may affect the healing of treated areas. These include retinoids and steroids, but these are not photosensitisers. Kerstein et al. [1] comment that the BMLA guidance concludes with a disclaimer that it is not an exclusive list of drugs, implying that some patients on other medications should not undergo laser therapy. In our opinion, it would be irresponsible for any guidelines not to include such a disclaimer but this does not imply that patients on other drugs should be excluded from treatment. Kerstein et al. [1] have produced a useful review, and we concur with the conclusion that the spectrum for drug-induced photosensitivity does not overlap with the wavelengths used by most lasers in medicine. It is always a difficult matter to strike the correct balance in producing guidelines. We urge all laser users to consider the advice within the BMLA guidelines. Ultimately, the responsibility for treatment lies with the laser operator.