The Food and Drug Administration (FDA) has approved testosterone undecanoate (Jatenzo), an oral testosterone capsule, for the treatment of low testosterone levels due to certain medical conditions such as Klinefelter syndrome or tumors that have damaged the pituitary gland. This is the first oral testosterone preparation available.

Testosterone undecanoate should not be used to treat men with low testosterone levels due to aging; the drug's risks are believed to outweigh its benefits for that use. The product labeling contains a black box warning for elevations in blood pressure, which can increase the risk of myocardial infarction, stroke, and cardiovascular death. Testosterone undecanoate is one of two testosterone preparations that carry this black box warning. The FDA is requiring a postmarketing trial to more clearly determine the effect of the product on blood pressure.

The most common adverse effects (seen in more than 2% of patients) include headache, an increase in hematocrit, a decrease in high-density lipoprotein cholesterol, high blood pressure, and nausea. An increase in prostate specific antigen (PSA) was also observed.

Nurses and NPs should inform patients prescribed testosterone undecanoate of the importance of returning for regular blood work to assess hematocrit, cholesterol, and PSA levels. If the patient has benign prostatic hyperplasia prior to starting testosterone undecanoate, he should be monitored for worsening urinary symptoms.

For complete prescribing information for testosterone undecanoate, see http://www.accessdata.fda.gov/drugsatfda_docs/label/2019/206089s000lbl.pdf.