Fractional inhibitory concentration (FIC) index

The sum of the FICs of each drug tested when used in combination.

The FIC for each drug is determined by dividing each drug’s MIC when used in combination by each drug’s MIC when used alone. The FIC index quantifies drug interactions and the value is used to categorize the interaction between drugs being tested.

CombiANT: Antibiotic interaction testing made easy (Plos Biology, 2020)

A multi-scale pipeline linking drug transcriptomics with pharmacokinetics predicts in vivo interactions of tuberculosis drugs (Scientific Reports, 2021)