Received April 27, 2021
Accepted October 31, 2021

Objective: To present the case of a man with normozoospermia and a high level of fragmented spermatozoa whose origin seems to be associated with long-term treatment with terbinafine hydrochloride. Case description: A male patient, 20 years old, healthy, with no history of disease and addictions, used an antifungal (terbinafine hydrochloride) for one year to treat a toenail. During this treatment, he participated in a research to evaluate a method of sperm DNA fragmentation analysis. A rate of 99% fragmented sperm was observed and primarily attributed to prolonged abstinence. Samples analyzed later indicated that the high fragmentation could be associated with the antifungal treatment and that with abstinence of 2 days and absence of treatment the fragmentation rate was again comparable with that of fertile men (15%). Conclusion: The use of terbinafine hydrochloride is likely to cause problems in male fertility affecting mainly the integrity of sperm DNA. Further studies are needed to confirm this observation and to determine at what level of the genitourinary tract the alteration of DNA occurs.