Iron supplements can interfere with the bioavailability of a number of drugs, including thyroxine, tetracycline derivatives, penicillamine, methyldopa, levodopa, carbidopa, ciprofloxacin, aid the newer fluoroquinolones. A new iron formulation was tested in which iron ions are bound to ovaltransferrin, a protein that shares more than an 80% similarity with the sequence of human transferrin and, apparently is less likely than the commonly used iron salts to reduce drug absorption. Ciprofloxacin was taken as a model drug, of wide use and restricted range of therapeutic levels, and its absorption was evaluated after the administration of the iron-ovotransferrin complex versus an iron-gluconate formulation high healthy volunteers. At variance with the iron gluconate formulation, which led to a reduction of about 50% of peak serum ciprofloxacin levels (C(max); 1.0 ± 0.2 versus 2.4 ± 0.3 μg/ml; p <0.01) and of the area under the serum concentration-time curve from time 0 to infinity [AUC(0-∞); 10.1 ± 1.1 versus 18.3 ± 1.0 mg · L-1 hr; p <0.01], the iron-ovotransferrin complex caused only modest, non significant changes in absorption with a minimal reduction of-the AUC(0-∞) (17.3 ± 1.0 versus 18.3 ± 1.0 mg L-1 hr; difference not significant) and a nonsignificant decrease in the C(max) (2.2 ± 0.3 versus 2.4 ± 0.3 μg/ml; difference not significant), Iron was also well absorbed from the formulation in the presence of a fatty meal. The very common drug interactions with oral iron preparations can be effectively prevented by the use of the iron-ovotransferrin complex interacting to a minimal extent with a sensitive drug with a reduced margin of efficacy, such as ciprofloxacin.
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