Page 182 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

➢ The fractional inhibitory concentration (FIC) index

FIC of drug A (FICA)= MIC of drug A in combination/ MIC of drug A alone

FIC of drug B (FICB)= MIC of drug B in combination/MIC of drug B alone.

FIC index = FICA + FICB.

In case of synergism: FIC index ≤ 0.5

Isobologram bend to inside

In case of additive: 0.5 < FIC index ≤ 1

Straight Isobologram

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