Background: While HIV, AIDS and atypical Mycobacterium infections are closely linked, the use of Integrase-Inhibitor\nbased cART, notably raltegravir-based regimens is more widespread. RAL should be double-dosed to 800 mg semi-daily\nin situation of rifampicin co-medication, because RAL is more rapidly metabolized due to rifampicin-induced\nUridine-5�-diphosph- gluronosyl-transferase (UGT1A1). Recently, it was speculated that chewed RAL might lead to\nincreased absorption, which might compensate the inductive effect of rifampicin-rapid metabolized RAL, as part\nof cost-saving effects in countries with high-tuberculosis prevalence and less economic power.\nMethods: We report measurement of raltegravir pharmacokinetics in a 34-year AIDS-patient suffering from\ndisseminated Mycobacterium avium infection with necessity of parenteral rifampicin treatment. RAL levels were\nmeasured with HPLC (internal standard: carbamazepine, LLQ 11 ng/ml, validation with Valistat 2.0 program\n(Arvecon, Germany)). For statistical analysis, a two-sided Wilcoxon signed rank test for paired samples was used.\nResults: High intra-personal variability in raltegravir serum levels was seen. Comparable Cmax concentrations were\nfound for 800 mg chewed and swallowed RAL, as well as for 400 mg chewed and swallowed RAL. While Cmax\nseems to be more dependent from overall RAL dosing than from swallowed or chewed tablets, increased AUC12\nis clearly linked to higher RAL dosages per administration. Anyway, chewed raltegravir showed a rapid decrease\nin serum levels.\nConclusions: We found no evidence that chewed 400 mg semi-daily raltegravir in rifampicin co-medication leads\nto optimized pharmacokinetics. There is need for more data from randomized trials for further recommendations
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