For a patient with symptomatic low testosterone started on transdermal testosterone, in addition to monitoring Prostate-Specific Antigen (PSA) levels, what else should be monitored?

Monitoring Parameters for Patients on Transdermal Testosterone Therapy

In addition to PSA monitoring, patients on transdermal testosterone therapy should be monitored for hematocrit/hemoglobin levels, cardiovascular risk factors, voiding symptoms, sleep apnea, and testosterone levels at regular intervals. 1

Essential Monitoring Parameters

Hematocrit/Hemoglobin

• Baseline measurement: Required before starting therapy 1
• Follow-up: Every 3-6 months for first year, then annually 1
• Action thresholds:
  • Baseline Hct >50%: Consider withholding therapy until etiology investigated 1
  • On-treatment Hct >54%: Requires intervention (dose reduction, temporary discontinuation, therapeutic phlebotomy, or blood donation) 1
• Risk consideration: Injectable testosterone carries higher risk of erythrocytosis (43.8%) compared to transdermal preparations (15.4% for patches, 5.5% for scrotal patches) 1
• Clinical significance: Secondary polycythemia in men on testosterone therapy increases risk of major adverse cardiovascular events and venous thromboembolism by 35% in the first year of therapy 2

Testosterone Levels

• First follow-up: 1-2 months after initiation to assess efficacy 1
• Timing of measurement:
  • For transdermal gel: Measure at +2 hours (peak) and +23 hours (trough) from application 3
  • Only 36.7% of patients maintain adequate levels at 23 hours post-application 3
• Target range: Mid to upper-normal physiologic range 1

Prostate Health

• Digital rectal examination: Baseline and at each follow-up visit 1
• PSA monitoring:
  • Baseline and at each follow-up visit 1
  • Action threshold: Yearly PSA increase of ≥1.0 ng/mL warrants prostate biopsy 1
  • If PSA increases by 0.7-0.9 ng/mL in one year, repeat PSA in 3-6 months 1

Voiding Symptoms

• Assessment method: International Prostatic Symptoms Score or history taking 1
• Frequency: At each follow-up visit 1
• Rationale: While prostate volume may increase during testosterone therapy, voiding symptoms typically don't worsen significantly 1

Sleep Apnea

• Screening: Assess for history of sleep apnea at baseline 1
• Monitoring: Evaluate for symptoms at each follow-up visit 1
• Risk factor: Testosterone therapy may exacerbate or trigger sleep apnea, particularly with higher doses 1

Cardiovascular Risk Factors

• Baseline assessment: Evaluate all fixed and modifiable ASCVD risk factors 1
• Optional: Lipid evaluation 1
• Caution: Use testosterone cautiously in men with congestive heart failure or renal insufficiency due to potential fluid retention 1

Follow-up Schedule

1. First follow-up: 1-2 months after initiation
2. Regular monitoring: Every 3-6 months for the first year
3. Long-term monitoring: Yearly after the first year 1

Additional Considerations

Fertility Concerns

• Inform patients that testosterone therapy compromises fertility due to gonadotropin down-regulation 1
• Testicular size and consistency often diminish 1
• Discuss fertility preservation options for patients interested in future fertility 1

Skin Reactions

• Monitor for local skin reactions, especially with patches (66% incidence) versus gels (5% incidence) 1
• Common reactions include erythema and pruritus 1

Breast Symptoms

• A small number of men may experience breast tenderness and swelling 1
• Consider measuring estradiol in patients who develop gynecomastia 1

Common Pitfalls to Avoid

1. Failure to monitor hematocrit: Secondary polycythemia significantly increases cardiovascular and thrombotic risk 2
2. Inadequate testosterone level monitoring: Levels can fluctuate significantly with transdermal preparations 3
3. Overlooking sleep apnea: Testosterone may worsen existing sleep-disordered breathing 1
4. Ignoring fertility concerns: Patients should be informed about potential impact on fertility 1
5. Misinterpreting PSA changes: Small increases may not indicate prostate cancer but require appropriate follow-up 1

By implementing this comprehensive monitoring protocol, clinicians can maximize the benefits of testosterone replacement therapy while minimizing potential risks to patient morbidity and mortality.