Maternal terbinafine use does not affect foetal, pregnancy outcomes

Exposure to oral or topical terbinafine during pregnancy does not increase the risk of major malformations and spontaneous abortion, according to a recent study.

“While terbinafine is a commonly used effective antifungal agent and generally well-tolerated [treatment] in the non-pregnant population, limited data exist on the foetal safety of use in pregnancy,” said the researchers.

“This nationwide cohort study found no increased risk of major malformations or spontaneous abortion among pregnancies exposed to oral or topical terbinafine. These results suggest that terbinafine can be used relatively safely in both oral and topical formulations during pregnancy,” they said.

Using data from the Denmark Medical Birth Registry and National Patient Registry between 1997 and 2016, researchers identified pregnancies exposed to oral terbinafine (n=891, mean age 30.4 years) and topical terbinafine (n=3,174, mean age 29.5 years) and matched them with 40,650 nonexposed pregnancies. Participants were divided into three comparison groups: group A (oral terbinafine exposed [n=522] vs unexposed [n=5,220]), group B (topical terbinafine exposed [n=1,476] vs unexposed [n=14,760]), and group C (oral vs topical terbinafine exposed [n=510 in each group]). [JAMA Dermatol 2020;doi:10.1001/jamadermatol.2020.0142]

The prevalence of major malformations was comparable among infants born to mothers who were exposed and unexposed to oral or topical terbinafine in all groups (group A: 3.8 percent vs 3.8 percent; prevalence odds ratio [OR], 1.01; group B: 3.6 percent vs 3.3 percent; prevalence OR, 1.08; and group C: 3.9 percent vs 3.3 percent; prevalence OR, 1.18).

Similarly, the risk of spontaneous abortion did not differ between pregnancies exposed and unexposed to oral or topical terbinafine (group A: 10.4 percent vs 10.3 percent; hazard ratio [HR], 1.06; group B: 5.2 percent vs 5.1 percent; HR, 1.04; and group C: 10.7 percent vs 9.6 percent; HR, 1.19).

In a sensitivity analysis, the researchers found no statistically significant association between oral terbinafine use and the risk of major malformations and spontaneous abortion.

“Oral terbinafine exposure in pregnancy was not associated with an increased risk of major malformations compared with unexposed pregnancies as well as compared with pregnancies exposed to topical terbinafine,” the researchers said. “Although our results may provide reassurance for pregnancies exposed to oral terbinafine … we cannot exclude a potential increased risk of a specific malformation … [These findings] should [also] be confirmed in other populations.”