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- Title
Serum Testosterone (T) Level Variability in T Gel-Treated Older Hypogonadal Men: Treatment Monitoring Implications.
- Authors
Swerdloff, Ronald S; Pak, Youngju; Wang, Christina; Liu, Peter Y; Bhasin, Shalender; Gill, Thomas M; Matsumoto, Alvin M; Pahor, Marco; Surampudi, Prasanth; Snyder, Peter J
- Abstract
<bold>Context: </bold>The optimal frequency for on-treatment serum T measurement used for dose adjustment after transdermal T gel application is unknown, especially in older men with thinner skin and slower metabolic clearance.<bold>Objectives: </bold>The objectives of the study was to determine the variability of postgel application serum T concentrations and assess whether single levels are reflective of average serum T concentrations over 24 hours (Cavg0-24).<bold>Design: </bold>This was a double-blinded, placebo-controlled randomized trial.<bold>Setting: </bold>The study was conducted at five academic centers.<bold>Participants: </bold>Forty-seven symptomatic men 65 years old or older with an average of two morning T concentration less than 275 ng/dL participated in the study.<bold>Intervention(s): </bold>Transdermal T or placebo gel was applied for 120 ± 14 days. Monthly dose adjustments were made if necessary to target serum T between 400 and 500 to 800 ng/dL.<bold>Main Outcome Measures: </bold>Variability of serum T 2 hours after the gel application on two outpatient visits and at multiple time points over 24 hours during the inpatient day was measured.<bold>Results: </bold>On-treatment T levels varied substantially on the 2 ambulatory days and over 24 hours during the inpatient day. Ambulatory 2-hour postapplication T levels did not correlate significantly with either 2-hour postapplication serum T or Cavg0-24 measured during the inpatient day. Only 22.2% of men receiving T had a Cavg0-24 within the target range of 500-800 ng/dL; 81.5% had a Cavg0-24 within the broader 300-1000 ng/dL range.<bold>Conclusion: </bold>Large within-individual variations in serum T after T gel application render ambulatory 2-hour postapplication T level a poor indicator of average serum T on another day. Our data point out the limitations of dose adjustments based on a single postapplication serum T measurement.
- Publication
Journal of Clinical Endocrinology & Metabolism, 2015, Vol 100, Issue 9, p3280
- ISSN
0021-972X
- Publication type
journal article
- DOI
10.1210/JC.2015-1542