Testosterone Replacement Therapy Side Effects and Monitoring

Introduction to Testosterone Replacement Therapy

The American College of Physicians recommends that testosterone replacement therapy be used with caution due to potential side effects, including erythrocytosis, which occurs in 2.8% to 43.8% of patients depending on formulation and dose 1

The Endocrine Society suggests that intramuscular testosterone injections carry the highest risk of erythrocytosis, with 43.8% of patients experiencing at least one elevated hematocrit (>52%) during treatment 1
Transdermal gel preparations show intermediate risk, with 11.3% at 50 mg/day and 17.9% at 100 mg/day experiencing erythrocytosis 1
Nonscrotal patches have the lowest incidence of erythrocytosis, at 2.8% 1
Most hemoglobin/hematocrit elevations occur within the first three months of therapy, with a strength of evidence rated as high 1
When hematocrit exceeds 54%, immediate intervention is mandatory, including dose reduction, temporary discontinuation, therapeutic phlebotomy, or blood donation, as recommended by the American College of Cardiology 2

The American Urological Association notes that prostate volume increases significantly during the first six months of therapy to levels equivalent to eugonadal men, with a strength of evidence rated as moderate 3
Multiple studies demonstrate no exacerbation of voiding symptoms or increased urinary retention rates compared to placebo, with a strength of evidence rated as high 3
The relationship between testosterone and prostate cancer remains controversial, with prospective studies showing only 1.1% cancer incidence, similar to the general population, and a strength of evidence rated as low 3

The American Academy of Dermatology reports that transdermal patches cause reactions in up to 66% of users, including erythema and pruritus, with a strength of evidence rated as high 4
Gel preparations cause skin reactions in only 5% of users, with a strength of evidence rated as moderate 4
Intramuscular injections commonly cause local pain, soreness, bruising, erythema, swelling, nodules, or furuncles, with a strength of evidence rated as high 4, 5

The American Thoracic Society notes that testosterone has been associated with exacerbation or new development of sleep apnea, particularly with higher doses, with a strength of evidence rated as moderate 4
Risk is highest in men receiving higher doses of parenteral testosterone who have other identifiable risk factors, with a strength of evidence rated as high 4

The American Heart Association recommends that fluid retention be monitored, as it is uncommon and typically mild, but may be problematic in men with congestive heart failure or renal insufficiency, with a strength of evidence rated as moderate 4
Leg swelling may indicate testosterone-induced erythrocytosis contributing to symptoms through increased blood viscosity, with a strength of evidence rated as low 2

The American Society for Reproductive Medicine notes that fertility will be greatly compromised during treatment, with a strength of evidence rated as high 4

The American College of Physicians recommends that baseline assessments include PSA, hematocrit/hemoglobin, digital rectal exam, voiding symptoms, and sleep apnea history, with a strength of evidence rated as high 6
First follow-up at 1-2 months to assess efficacy and early side effects, with subsequent visits every 3-6 months for the first year, then yearly, with a strength of evidence rated as moderate 6, 2