Metformin Cefalexin

In a double-blind, randomized, crossover study in 12 healthy volunteers, cefalexin 500 mg increased the Cmax and AUC of a single dose of metformin 500 mg by 34 and 24% respectively and reduced its renal clearance to 14% (138). The authors suggested that cefalexin inhibits the renal tubular secretion of metformin. 

Cefalexin modestly increased the serum levels of metformin in a single-dose study. 

In a placebo-controlled study in 12 healthy subjects cefalexin 500 mg increased the AUC and maximum serum levels of a single 5(X)-mg dose of metformin by 24% and 34%, respectively. Cefalexin reduced the renal clearance of metformin by 14% by inhibiting metformin tubular secretion via the organic cation system. The clinical relevance of these small changes is uncertain, but they could be greater with longer-term use. The authors recommend that patients receiving metformin with cefalexin should have metformin levels monitored or an alternative antibacterial to cefalexin should be considered. However, based on the available evidence this seems somewhat overcautious. 

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See also in sourсe #XX -- [ ]

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