Can flucloxacillin be used in a patient who is being treated with isotretinoin?/nA 14-year-old girl

Fråga: Can flucloxacillin be used in a patient who is being treated with isotretinoin?

A 14-year-old girl treated with isotretinoin (Roaccutan) for two weeks, is in need of treatment with antibiotics due to a soft tissue infection. According to the patients dermatologist isotretinoin should not be combined with certain antibiotics. Can the infection be treated with flucloxacillin?

Sammanfattning: The reason why tetracycline antibiotics should not be combined with isotretinoin is an added risk for pseudotumor cerebri. For flucloxacillin we have not found any reports of this adverse effect. Besides, no reported cases of other interactions between flucloxacillin and isotretinoin were found.

Svar: The plasma half-life is commonly 10-20 hours for isotretinoin and 17-50 hours for its metabolite 4-oxo-isotretinoin (1). Consequently, there is seldom time to interrupt treatment with this drug at the prospect of initiation of antibiotics. Tetracycline antibiotics and isotretinoin should not be combined on account of an added risk for pseudotumor cerebri, which is a known but rare adverse effect for each of these drugs (2). We have not found any reported cases of pseudotumor cerebri for flucloxacillin, which is an isoxazolylpenicillin. Therefore, and in view of the mechanism for the interaction mentioned above, it is unlikely that initiation of flucloxacillin in a patient taking isotretinoin would increase the risk for this adverse effect. Furthermore we have not found any reports on other interactions between these two substances. Isotretinoin. Drugdex(R) System; Micromedex, Inc., Englewood, Colorado (Edition expires (date)) Drugline nr 10880 (year 1994)