Nifedipine Cefixime

An active dipeptide transport system that depends on hydrogen ions takes up non-ester amino-beta-lactams (penicillin, amoxicillin, and oral first-generation cephalosporins) (337-339) and specific cephalosporins that lack the alpha-amino group (cefixime, ceftibuten, cefdinir, cef-prozil) (340,341). Nifedipine increases amoxiciUin and cefixime absorption, probably by stimulating the dipeptide transport system, since the serum concentrations of passively absorbed drugs and intestinal blood flow did not change (342-344). 

Duverne C, Bouten A, Deslandes A, Westphal JF, Trouvin JH, Farinotti R, Carbon C. Modificahon of cefixime bioavailabihty by nifedipine in humans involvement of the dipeptide carrier system. Antimicrob Agents Chemother 1992 36(ll) 2462-7. 

Nifedipine increases the serum levels of cefixime but this is uniike-ly to be clinically important. Neither nifedipine nor diitiazem affect the pharmacokinetics of cefpodoxime proxetil. 

In 8 healthy subjects the AUC and peak serum levels of a single 200-mg dose of cefixime were increased by about 70% and 50%, respectively, when cefixime was taken 30 minutes after a 20-mg dose of nifedipine. The rate of absorption was also increased. One suggested reason for this interaction is that the nifedipine increases the absorption of the cefixime by affecting the carrier system across the epithelial wall of the gut. It seems doubtful if this increased cefixime bioavailability is clinically important (the combination was well-tolerated) and no particular precautions would seem to be necessary on concurrent use. 

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