. 2024 Jan 8;14:1349550. doi: 10.3389/fmicb.2023.1349550

Table 4.

FIC values for the combinations with carvacrol.

Tested product	FIC	Interpretation	MIC before combination (μg/mL)	MIC after combination (μg/mL)
Carvacrol + minocycline	0.046	Synergistic effect	Carvacrol = 4,000	Carvacrol = 62.5
Carvacrol + minocycline	0.046	Synergistic effect	Minocycline = 250	Minocycline = 7.8
Carvacrol + linezolid	1.004	Additive effect	Carvacrol = 4,000	Carvacrol = 15.6
Carvacrol + linezolid	1.004	Additive effect	Linezolid = 250	Linezolid =250
Carvacrol + sulfamethoxazole	1.125	Indifferent effect	Carvacrol = 4,000	Carvacrol = 500
Carvacrol + sulfamethoxazole	1.125	Indifferent effect	Sulfamethoxazole = 4,000	Sulfamethoxazole = 4,000
Carvacrol + trimethoprim	0.039	Synergistic effect	Carvacrol = 4,000	Carvacrol = 31.25
Carvacrol + trimethoprim	0.039	Synergistic effect	Trimethoprim = 4,000	Trimethoprim = 125

The FIC index is interpreted as <0.5 is a synergistic effect, 0.5–1 is an additive effect, 1–4 is an indifferent effect, and more than 4 is an antagonistic effect.