Antimicrobial drug-nutrition interactions: Consistency of information for generic drugs

Background/Aim. Antimicrobial drug-nutrition interactions can compromise the efficacy and safety of therapeutic regimen, as well as the nutritional status of a patient. In order to prevent them, health professionals consult the reference information sources. Summary of Product Characteristics (SmPC) is the basis for reliable and objective informing, and in the case of generic products, the content of documents should be consistent. The aim of the study was to compare information on antimicrobial drug-nutrition interactions for generic products, and to consider the influence of relevant factors (the time of the first authorization and the number of generic products) on the outcome of evaluation. Methods. SmPCs for all generic antimicrobial products for systemic use were retrieved from the Medicines and Medical Devices Agency of Serbia website, and statements of interest were extracted from different sections and were compared. The comparison was based on classification of statements on interaction into one of five classes: "effect of nutrition status on drug action", "effect of food in general on drug action", "effect of specific nutrient on drug action", "effect of drug on nutrient and metabolic status", or "effect of drug on nutrition status". Results. A total of 160 SmPCs were evaluated for 30 antimicrobial drugs corresponding to 46 dosage forms [mean number 3.48, standard deviation (SD) = 1.68; median 3.00, interquartile range (IQR) = 2; range: 2-9]. Nine (30%) antimicrobials (azithromycin, clarithromycin, cefazolin, cefepime, pipemidic acid, ciprofloxacin, levofloxacin, moxifloxacin and gentamicin) had inconsistent information. The inconsistency was related to different classes of interactions, and in some cases it could have clinically important implications (gentamicin, fluoroquinolones). The existence of a larger number of generic products was related to identified differences (p = 0.003). Conclusion. One third of generic antimicrobial products had inconsistent drug-nutrition interaction statements. Given the potential clinical implications, strategies for further harmonization of this information should be considered.