Purpose: To evaluate the effect of short-acting 4.5% nasal testosterone gel (Natesto) on serum testosterone, gonadotropins, total motile sperm count, health related quality of life and sexual function.
Materials and methods: This was a single institution, open label, single arm trial conducted between November 2017 and September 2019 at the University of Miami. Men 18 to 55 years old diagnosed with symptomatic hypogonadism (total testosterone less than 300 ng/dl on 2 occasions) were included. Men with azoospermia, vasectomy or a total motile sperm count less than 5 million were excluded. Enrolled patients were treated with Natesto, a short-acting nasal testosterone (125 μl per nostril, 11.0 mg testosterone per dose, TID) for 6 months.
Results: In total, 60 men were enrolled in the study. Of these, 44 and 33 patients were evaluated for testosterone at 3 and 6 months, respectively. A total of 31 patients (90.9%) reached a normal testosterone level (greater than 300 ng/dl) at 6 months. Follicle stimulating hormone and luteinizing hormone levels were maintained within the normal range in 81.8% and 72.7% of patients at 6 months, respectively. Total motile sperm count was maintained with total motile sperm count greater than 5 million over the treatment period in 88.4% of men at 3 months and 93.9% at 6 months. There were statistically significant improvements on International Index of Erectile Function sexual desire and overall satisfaction domains at 6 months.
Conclusions: Natesto appears to increase testosterone while maintaining semen parameters in a majority of men. Natesto has the potential to be a safe and effective treatment for men with functional hypogonadism who wish to preserve semen parameters. Long-term studies beyond 6 months are needed before we can safely prescribe nasal testosterone gel for men interested in fertility.
Keywords: nasal absorption; oligospermia; pulsatile flow.