Testosterone replacement with transdermal therapeutic systems. Physiological serum testosterone and elevated...

Area of Science:

• Endocrinology
• Andrology
• Pharmacology

Background:

• Hypogonadism is a condition characterized by the inability to produce sufficient testosterone.
• Transdermal testosterone delivery systems offer a potential method for testosterone replacement therapy (TRT).

Purpose of the Study:

• To evaluate the efficacy and safety of transdermal testosterone administration in hypogonadal men.
• To determine optimal dosing and assess long-term maintenance of testosterone levels.

Main Methods:

• Three transdermal testosterone administration protocols were used in hypogonadal men.
• Serum testosterone and dihydrotestosterone (DHT) levels were monitored over 12 weeks and up to one year.
• Dosing varied between 5 mg, 10 mg, and 15 mg transdermal systems applied scrotally.

Main Results:

• Peak testosterone levels were achieved 3-8 hours post-application, with levels at 22 hours exceeding 60% of peak.
• Serum testosterone levels increased significantly from baseline (1.5 nmol/L) to physiological ranges (15.2-18.6 nmol/L) within 12 weeks.
• The testosterone/DHT ratio decreased, indicating a proportionally greater increase in DHT with transdermal delivery.
• Long-term treatment (up to one year) in compliant patients maintained testosterone levels within the physiological range.

Conclusions:

• Transdermal testosterone administration can achieve physiological serum testosterone levels in two-thirds of hypogonadal men.
• The scrotal application of transdermal therapeutic systems provides effective testosterone delivery and sustained hormone levels.
• Further monitoring of the testosterone/DHT ratio is warranted for long-term transdermal TRT.