Safety and Efficacy of Testosterone Nasal Gel
Natesto Nasal Gel, a testosterone nasal gel has been recently approved by the US Food and Drug Administration (FDA) for treating adult males who are suffering from conditions associated with absence or deficiency of endogenous testosterone. These conditions include congenital or acquired primary hypogonadism or hypogonadotrophic hypogonadism.
What is Hypogonadism?
Testosterone is the hormone which is responsible for the growth and development of the sex organs in males and for the maintenance of secondary sexual characteristics.
Hypogonadism is a condition in which there is decreased production of testosterone as the testes, hypothalamus or pituitary glands are damaged by disease. Low testosterone may result in erectile dysfunction, loss of sexual appetite, depression, osteoporosis, regression of secondary sexual characteristics and generalized lethargy.
It is estimated that almost 13 million American men are suffering from conditions associated with low testosterone production. Currently, these men are dependent upon exogenous testosterone preparations like intramuscular injections, transdermal patches, buccal patches, tablets to be consumed orally and topical testosterone gels.
Phase III Trial for Natesto
Natesto testosterone gel had to undergo a multicenter, 90 day phase III trial to test its safety and efficacy before it was approved by the FDA. In this trial, 306 hypogonadal men were enrolled at 39 clinical research centers across the US. The average age of these men was 54 years. All of them were administered Natesto intranasally for 90 days. While 228 of the men used it in both nostrils twice a day, 78 of them used it thrice a day. This randomization was done in order to find the most effective dose of the testosterone nasal gel. 73 of these men were asked to continue the treatment for further 90 days to evaluate the effects of the medicine and development of tolerance.
After the end of the initial 90 days of treatment, it was seen that in 90% of men who used the testosterone nasal gel three times a day, the average testosterone concentration in the blood was in the normal range. This concentration of testosterone in the blood was seen in 71% of men who used the gel twice a day. The patients noticed an improvement in erectile dysfunction. Only 3.7% of the patients had to discontinue the treatment because of side effects like headache, rhinorrhea, sinusitis and epistaxis.
Appropriate Dosage of Testosterone Nasal Gel
According to Trimel Pharmaceuticals, the manufacturers of Natesto testosterone nasal gel, the product can be self-administered into each of the nostrils. It comes with a metered dose pump applicator. Every time the pump is pressed, it releases 5.5 mg of testosterone. The recommended dose is 11 mg at one time i.e. 1 pump actuation in each nostril. It should be taken three times daily so that 33 mg of testosterone is administered each day.
Drawbacks of Testosterone Nasal Gel
Critics of testosterone nasal gel point out to the side effects of the medicine observed during the phase III trials. They are also not sure how effective the medicine would be when it is administered in the intranasal form in a patient suffering from a runny nose.
When the nasal gel was tested in mice, the levels of testosterone in brain were twice as high as compared to the levels of the hormone observed in the brains of mice who received the drug in the intravenous form. Scientists have yet to ascertain the level of testosterone in the brain of men who receive it through the nasal gel and what would be the effect of such high levels of testosterone in the brain. Therefore, they have advised the physicians to use the nasal gel with caution.
“Testosterone Nasal Gel Works Best at Three Doses a Day, Study Finds,” published in Endocrine.org on March 7, 2015, accessed on March 28, 2015. Retrieved from: