The pharmacokinetics data of the testosterone gel applied to the axillae are comparable to the other testosterone gels . A 2% hydro-alcoholic testosterone gel that shows similar pharmacokinetics as other gels is available as is another 2% testosterone gel that does not contain alcohol and is applied to the axilla using an applicator. In the US, the gel formulations that are currently available are 1, 1.62 and 2% testosterone gel. During pregnancy, the placenta secretes hCG, which stimulates the corpus luteum — a temporary structure within the ovaries — to produce the hormone progesterone. Consent was obtained or waived by all participants in this study. For men requiring T therapy who are at risk of secondary erythrocytosis, the use of hCG should be investigated further. Secondary erythrocytosis is a common adverse effect of T therapy and can lead to MACEs and VTEs. Twenty-one patients (75%) injected hCG once weekly, six patients (21%) injected twice weekly, and one patient (4%) injected three times weekly. The "On T" group had their baseline labs completed within the therapeutic window of their respective previous exogenous T therapy Twenty-eight men who had a history of exogenous T use were included in the study. Additionally, it was noted if their pre-hCG/baseline labs were collected while the patient was using exogenous T. They found a significant increase in mean serum T levels from 0.90 ±1.35 to 5.58 ±1.75 ng/mL after 24 weeks. A 1992 study by Vicari et al. using 1500 IU hCG three times weekly for 24 months in 17 men, with both large and small testes, demonstrated a statistically significant increase in plasma T levels . Grouped according to patients who were taking ("On T") or not taking ("Off T") exogenous T during their pre-hCG/baseline labs. Demographic information based on the status of patients being on or off T for their pre-hCG monotherapy labs can be seen in Table 1. When available, two pre- and post-hCG T serum levels were included for each patient. Testosterone replacement therapy leads to increase in DHT levels through conversion by 5 α reductase enzymes. Because intraprostatic levels of 5 α dihydrotestosterone (DHT) are higher than testosterone, DHT is considered the important intrapro-static androgen that regulates growth and proliferation of prostate tissue. In the meantime until such data are available, clinicians should discuss with and monitor cardiovascular events in older hypogonadal men who will start testosterone treatment. The above reports are observational studies that do not imply causality; or meta-analyses where the primary data may not be available; or data based on prescriptions where the basis for the diagnosis of hypogonadism and co-treatment medications are not known. However, such an increase was not noted in another randomized placebo-controlled study on testosterone treatment in frail older men . A meta-analyses of testosterone replacement therapy clinical trials showed no increase in cardiovascular adverse events . Further large scale longitudinal studies are needed to ascertain the effects of testosterone replacement therapy in men with OSA. Hypogonadal men with moderate to severe obstructive sleep apnea (OSA) are at an increased theoretical risk for exacerbation of OSA with testosterone replacement therapy, particularly if supra-physiologic doses of testosterone are used 1,55,84-86. The most common adverse effect of testosterone replacement therapy is increase in hemoglobin, hematocrit and red cell indices . Common adverse events of testosterone replacement therapy include development of acne and increased oiliness of skin because of the androgenic effects on sebaceous gland.
