From the Guidelines
Blood work for patients on Natesto should be monitored every 6-12 months to ensure target testosterone levels are achieved and maintained. According to the American Urological Association (AUA) guideline 1, testosterone levels should be measured every 6-12 months while on testosterone therapy. This recommendation is based on expert opinion and aims to balance the need for monitoring testosterone levels with the potential risks and benefits of therapy.
When monitoring blood work, it is essential to consider the following parameters:
- Total testosterone levels, ideally drawn 1-2 hours after Natesto application for peak levels
- Complete blood count to monitor for polycythemia (increased red blood cell production)
- Lipid panel
- Liver function tests
- PSA (prostate-specific antigen) in men over 40 years old
The AUA guideline 1 also suggests measuring an initial follow-up total testosterone level after an appropriate interval to ensure that target testosterone levels have been achieved. However, the specific timing of this initial follow-up measurement is not defined, and the general recommendation of monitoring every 6-12 months is considered the standard of care.
It is crucial to individualize the monitoring schedule based on patient response, with more frequent monitoring for patients showing abnormal results or experiencing symptoms of either too high or too low testosterone levels. The goal of monitoring is to ensure that testosterone levels remain in the therapeutic range while detecting potential side effects early, ultimately prioritizing morbidity, mortality, and quality of life outcomes.
From the FDA Drug Label
To ensure proper dosing, the dose should be titrated based on the pre-dose morning serum testosterone concentration from a single blood draw at approximately 14 days and 28 days after starting treatment or following dose adjustment. In addition, serum testosterone concentration should be assessed periodically thereafter
The patient's blood work should be monitored at approximately 14 days and 28 days after starting treatment with Natesto or following dose adjustment, and periodically thereafter to assess serum testosterone concentration. 2
From the Research
Monitoring Blood Work on Natesto
To determine how often to monitor blood work when on Natesto, we can look at the following studies:
- The study 3 monitored testosterone levels at 3 and 6 months in men with symptomatic hypogonadism treated with Natesto.
- The study 4 evaluated the efficacy and safety of testosterone nasal gel in hypogonadal males over a 90-day period, with some patients being followed for up to 1 year.
- The study 5 collected total testosterone levels at day 90 and 120 in hypogonadal males treated with Natesto.
- The studies 6 and 7 discussed the effects of testosterone therapy on laboratory profiles, including hemoglobin, hematocrit, and lipid profiles, but did not specifically address the frequency of monitoring blood work on Natesto.
Key Findings
Some key findings from these studies include:
- Testosterone levels should be monitored to ensure they are within the normal range (greater than 300 ng/dl and less than 1050 ng/dl) 4.
- Monitoring of hemoglobin and hematocrit levels is also important, as testosterone therapy can cause increases in these parameters, potentially leading to erythrocytosis or polycythemia 6, 7.
- The frequency of monitoring blood work may depend on individual patient factors, such as symptoms and medical history.
Blood Work Parameters to Monitor
The following blood work parameters may be important to monitor in patients on Natesto:
- Testosterone levels
- Hemoglobin and hematocrit levels
- Lipid profiles
- Liver function tests
Frequency of Monitoring
Based on the available studies, it is recommended to monitor blood work at the following frequencies: