What should the dosing instructions be for a 36-year-old male's testosterone replacement therapy (TRT) prescription?

Testosterone Replacement Therapy Dosing Instructions

For a 36-year-old male on testosterone replacement therapy, the prescription should include 1.62% testosterone gel applied to clean, dry, intact skin of the upper arms and shoulders once daily, with an initial dose of 40.5 mg (2 pump actuations or one 40.5 mg packet) and target total testosterone levels of 450-600 ng/dL. 1, 2

Application Instructions

Site and Method

• Apply only to upper arms and shoulders (not abdomen, genitals, chest, armpits, or knees) 2
• Application area should be limited to what can be covered by a short-sleeve t-shirt 2
• For 40.5 mg dose:
  • Using pump: Apply 1 pump actuation to each upper arm/shoulder (total 2 actuations) 2
  • Using packets: Apply half of one 40.5 mg packet to each upper arm/shoulder 2

Application Technique

• Apply with palm of hand and spread across maximum surface area 2
• Allow application site to dry completely before covering with clothing 2
• Wash hands thoroughly with soap and water immediately after application 2
• Avoid swimming, showering, or washing the application site for at least 2 hours after application 2

Monitoring and Dose Adjustments

Initial Monitoring

• Check testosterone levels 2-3 months after treatment initiation 1
• First follow-up visit at 1-2 months to assess efficacy 1
• Morning testosterone level should be measured pre-dose for accurate monitoring 1

Dose Adjustment Protocol

• Adjust dose based on pre-dose morning total serum testosterone concentration:

  • 750 ng/dL: Decrease daily dose by 20.25 mg (1 pump actuation)

  • 350-750 ng/dL: No change, continue current dose
  • <350 ng/dL: Increase daily dose by 20.25 mg (1 pump actuation) 2

Ongoing Monitoring

• Monitor every 6-12 months once stable levels are confirmed 1
• Check hematocrit/hemoglobin, PSA, and lipid profile 1
• Target parameters:
  • Total testosterone: 450-600 ng/dL
  • Hematocrit: <54% (discontinue if exceeds this threshold)
  • PSA: Consider biopsy if >4.0 ng/mL or increases >1.0 ng/mL/year 1

Important Precautions

Secondary Exposure Prevention

• Cover application site with clothing after gel has dried 2
• Children and women should avoid contact with unwashed application sites 2
• Wash application site thoroughly before skin-to-skin contact 2
• If someone else contacts the application site, they should wash the area with soap and water immediately 2

Safety Considerations

• Avoid fire, flames, or smoking until gel has dried (product is flammable) 2
• Upper arms/shoulders application provides optimal absorption compared to other sites 3
• Transdermal gel provides more stable testosterone levels compared to injections 1

Clinical Pearls and Pitfalls

• The application site significantly affects absorption - arms/shoulders provide better absorption than chest/abdomen or legs 3
• Incorrect use accounts for many treatment failures; ensure patient understands proper application technique 4
• Contraindications include active prostate or breast cancer, hematocrit >50%, severe untreated sleep apnea, severe lower urinary tract symptoms, uncontrolled heart failure, and desire for current or future fertility 1
• Potential adverse effects include erythrocytosis, fluid retention, and prostate effects requiring monitoring 1
• Testosterone therapy is not an effective monotherapy for erectile dysfunction; if ED is present, consider combination with PDE5 inhibitors 4