Abstract: Objective To investigate the in vitro testing of amorolfine in combination with terbinafine or itraconazole against 80 strains of pathogenic fungi isolated from onychomycosis patients. Methods M27-A and M38-P guidelines were applied. The MIC endpoint was determined as the first concentration of antifungal agent that reach at least 80% inhibition of growth compared with the control well. The FIC value of < 1 denoted synergy; a value of 1-2 indicated either an additive or indifference, and > 2 was taken to be antagonistic. Results The GM (geometrical mean) of MICs of amorolfine, terbinafine and itraconazole to dermatophytes were 0.0396, 0.012 and 0.309 μg/mL, respectively. The total percentages of showing potentially synergistic activity (FIC < 1) for amorolfine + terbinafine and amorolfine + itraconazole were 67.12% and 66.67%, respectively. There was no significant difference between these two groups (P>0.05). To dermatophytes the figures were 65% and 75%(P>0.05), while to nondermatophyte the difference was significant (P<0.05). No antagonism was observed. Conclusion The combinations of amorolfine + terbinafine and amorolfine + itraconazole revealed a good synergy against dermatophyte, yeast and moulds.

Key words: Onychomycosis, Microbial sensitivity tests, Antibiotics, antifungal