Brand name: Natesto
Generic name: testosterone nasal gel
Medication Class: Testosterone, Androgens
Similar drugs: Androderm, AndroGel, Axiron, Fortesta, Striant, Testim, Testopel Pellets, Testro AQ, Vogelxo
Manufacturer: Trimel Pharmaceuticals Corporation
FDA Approval Date: May 28, 2014
What is Natesto and its mechanism of action?
Natesto is a testosterone gel that is applied into the nose. After absorption, it produces about 300-1050 ng/dL (nanograms per deciliter) of circulating testosterone in the blood stream. This is the normal amount of testosterone in healthy men. The maximum concentration of Natesto is achieved within 40 minutes of use. The half-life (the amount of time it takes for the concentration to be reduced by half) is 10 to 100 minutes.
Testosterone plays an important role in adult men. It is needed for normal male sexual development, and for the prostate, penis, scrotum and seminal vesicle to grow and mature. Testosterone is also needed for the changes that occur during puberty such as deepening of the voice and growth of hair on the face and body. It also plays a role in production of sperm.
Testosterone is an androgen (steroid hormone) that is produced by the testes. If the testes do not work properly, this can lead to hypogonadism, causing a lower than normal level of testosterone to be produced. There are two types of hypogonadism: primary and secondary. Primary hypogonadism occurs when the testes are not working normally, for instance due to normal aging, or diseases such as Klinefelter’s syndrome, or when the testes have been removed as a result of testicular or prostate cancer.
Secondary hypogonadism occurs if the pituitary or hypothalamus is not functioning normally. The hypothalamus is a part of the brain that stimulates the pituitary gland to release hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones stimulate the testes to produce testosterone. Therefore if there is a problem with the hypothalamus or the pituitary (such as pituitary tumor), this can reduce the production of testosterone, and lead to hypogonadism. Secondary hypogonadism is also known as hypogonadotropic hypogonadism.
What is Natesto used to treat?
Natesto is used to treat males who produce lower than normal amounts of testosterone or none at all. This could be due to primary or secondary (hypogonadotropic) hypogonadism. Hypogonadism could occur after birth (known as acquired), or it could be a condition you are born with (congenital). Natesto is FDA-approved to both cases of hypogonadism.
How effective is Natesto?
A clinical study of 306 men with hypogonadism was done to determine how well Natesto works. These men were 18 years or older and had morning testosterone concentrations of 300 ng/dL or lower. The duration of treatment was 90 days.
73 men who had used 11 mg of Natesto three times daily had their average serum total testosterone tested. On the day 90, 90% of them had an average serum total testosterone concentration within the normal range (300 to 1050 ng/dL) and 10% had levels below the normal range (less than 300 ng/dL). None of them had levels higher than the normal range (more than 1050 ng/dL).
Interesting Facts about Natesto
Natesto is a schedule III (CIII) controlled substance due to its potential for abuse and dependence
Testosterone, prostate-specific antigen (PSA), hemoglobin, hematocrit, lipid levels and liver function should be monitored while taking Natesto.
What are the side effects of Natesto?
Common side effects include nasal discomfort, upper respiratory tract infection, sinusitis (sinus infection), rhinorrhea (runny nose), nasopharyngitis, bronchitis, epistaxis (nose bleed) and headache. It can also cause an increase in prostate specific antigen (PSA).
Polycythemia, an increase in the number of red blood cells (RBCs) in the blood can occur. This can increase the risk of getting venous thromboembolism (blood clots in the veins). Patients who have pain, edema (fluid retention), warmth and erythema (redness) in the legs or sudden shortness of breath should seek medical treatment immediately.
There have also been post marketing reports of patients with polycythemia developing blood clots. As a result, the FDA is requiring a change in the drug labeling of all testosterone products to warn consumers of the risk of blood clots in the veins. In addition, the FDA is continuing to evaluate the possible risk of stroke, heart attack and death in patients taking testosterone products.
Increased risk of prostate cancer and worsening benign prostatic hyperplasia (BPH) symptoms due to an increase in testosterone levels.
A reduction in sperm count may occur with large doses.
Natesto may cause the body to retain fluid and increase the risk of heart failure.
Liver problems may occur. Patients should report any symptoms such as weakness and fatigue (tiredness), weight loss, nausea, vomiting, and yellowing of the skin and eyes.
Natesto may cause gynecomastia (breast enlargement in males), increase in lipids and hypercalcemia (higher than normal calcium levels in blood).
Sleep apnea may occur in patients with risk factors such as obesity or chronic lung disease.
Natesto may also reduce T4 serum concentrations. T4 (thyroxine) is a hormone produced by the thyroid gland. A lower than normal amount of T4 may indicate hypothyroidism, while a higher than normal amount may indicate hyperthyroidism. However, the reduction of T4 levels caused by Natesto has not been found to have any effect on thyroid function.
What is the dosage of Natesto?
Natesto is available in a 5.5 mg/0.122 g actuation metered dose pump. One pump actuation delivers 5.5 mg of testosterone in 0.122 g (122.5 mg) of gel.
The recommended dose of Natesto is 11 mg of testosterone (total of two pumps; one pump per nostril) administered intranasally three times a day for a total daily dose of 33 mg.
What are the drug interactions of Natesto?
The following are some examples of drugs that may interact with Natesto:
Natesto may affect factors that help blood to clot. This could affect how warfarin works and increase the risk of bleeding. Monitoring of international normalized ratio (INR) and prothrombin time should be done more frequently, especially when starting or stopping Natesto.
Natesto may increase sensitivity to insulin. This could lead to a decrease in blood sugar and increase the risk of hypoglycemia (lower than normal blood sugar) in diabetics. Insulin doses may need to be adjusted while taking Natesto.
Corticosteroids such as fludrocortisone (Florinef) may cause the body to retain fluid. This risk increases when Natesto is used at the same time. Patients should be monitored for fluid retention, especially patients with liver, kidney or heart disease.
Clinical studies showed that patients with symptomatic seasonal rhinitis (seasonal allergies) who used oxymetazoline 30 minutes before Natesto had reduced absorption of Natesto. This was due to the rhinitis. When oxymetazoline was used in patients without rhinitis, there was no effect on the absorption of Natesto. Patients with severe rhinitis should temporarily stop using Natesto until symptoms resolve. If the rhinitis persists, patients should consult their doctor since a different testosterone treatment may be needed.
There are other medications that can interact with Natesto. Patients should consult their physician or pharmacist to confirm drug interactions with specific products.
What are the warnings and precautions of Natesto?
Patients with a history of nasal disorders, nasal or sinus surgery, mucosal inflammatory disorders (such as Sjogren’s syndrome), sinus disease or a nasal fracture within the past 6 months should not use Natesto since it has not been tested in these patients.
Natesto should not be used with other intranasal drugs since potential drug interactions have not been tested.
Natesto has not been tested in males younger than 18 years old.
Serum total testosterone concentrations should be checked periodically, starting one month after starting treatment with Natesto. If the total testosterone concentration consistently exceeds 1050 ng/dL, Natesto should be discontinued. If the total testosterone concentration is consistently below 300 ng/dL, an alternative treatment should be considered.
Natesto should not be used in men with breast or prostate cancer.
Pregnancy Category X — Natesto should not be used by pregnant women or women who may become pregnant since it can harm the fetus.
Nursing mothers. Natesto may harm nursing infants and should not be used if breastfeeding.
What is the cost of Natesto?
The price of Natesto has not yet been finalized.
Snyder, Peter. Causes of primary hypogonadism in males. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. Accessed July 10, 2014.
Snyder, Peter. Causes of secondary hypogonadism in males. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. Accessed July 10, 2014.
Snyder, Peter. “Clinical features and diagnosis of male hypogonadism.” In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Updated Jan 18, 2013). Accessed July 10, 2014.