What monitoring labs are recommended for patients on AndroGel (testosterone) and a Glucagon-like peptide-2 (GLP-2) agonist?

Monitoring Labs for Patients on AndroGel and GLP-2 Agonists

Patients on AndroGel (testosterone) and GLP-2 agonists should undergo regular monitoring of serum testosterone, prostate-specific antigen (PSA), hemoglobin, hematocrit, liver function tests, lipid profile, blood glucose, and renal function. 1

Testosterone (AndroGel) Monitoring

Baseline and Periodic Monitoring

• Complete blood count with hemoglobin and hematocrit to monitor for erythrocytosis 1, 2
• Liver function tests to detect potential hepatic effects 1
• Lipid profile to monitor cardiovascular risk 1
• PSA and digital rectal examination for prostate health monitoring 1, 2
• Blood pressure measurements to detect hypertension 1
• Serum testosterone levels to ensure appropriate dosing 2

Frequency of Monitoring

• Initial follow-up: 3 months after starting therapy 2
• Subsequent monitoring: Every 6-12 months if stable 2
• More frequent monitoring may be necessary in patients with pre-existing cardiac, renal, or hepatic disease 1

Special Considerations

• Monitor for signs of fluid retention, especially in patients with cardiac, renal, or hepatic disease 1
• Monitor for sleep apnea in at-risk patients 1
• Monitor for signs of benign prostatic hyperplasia (BPH) worsening 1

GLP-2 Agonist Monitoring

Baseline and Periodic Monitoring

• Renal function tests (eGFR, serum creatinine) 3
• Blood glucose levels, especially in patients with diabetes 3
• Bone turnover markers (if clinically indicated) 4
• Parathyroid hormone (PTH) levels (if clinically indicated) 4

Frequency of Monitoring

• Initial follow-up: 2-8 weeks after starting therapy 3
• Subsequent monitoring: Every 3-6 months 3

Combined Therapy Considerations

Drug Interactions

• More frequent monitoring of blood glucose in diabetic patients as testosterone may decrease insulin requirements 1
• More frequent monitoring of INR and prothrombin time in patients on anticoagulants 1
• Careful monitoring for fluid retention in patients also on corticosteroids 1

Special Populations

• In patients with chronic kidney disease:
  • Monitor eGFR more frequently 3
  • Monitor for signs of volume depletion 3
  • Consider more frequent electrolyte monitoring 1

Common Pitfalls to Avoid

• Failure to monitor PSA and hematocrit: These are critical safety parameters for testosterone therapy 1
• Inadequate glucose monitoring: Testosterone can affect insulin sensitivity and glycemic control 1
• Overlooking fluid retention: Both medications can affect fluid balance, especially in patients with cardiac, renal, or hepatic disease 1
• Neglecting bone health: GLP-2 agonists can affect bone turnover markers 4

Monitoring Algorithm

1. Baseline assessment (before starting therapy):

   • Complete blood count
   • Comprehensive metabolic panel
   • Lipid profile
   • PSA (for men over 40)
   • Blood pressure
   • Serum testosterone level
   • Bone turnover markers (if clinically indicated)

2. Early follow-up (2-8 weeks):

   • Blood glucose monitoring
   • Assessment for fluid retention
   • Renal function tests

3. Regular monitoring (every 3-6 months for first year, then every 6-12 months if stable):

   • Complete blood count
   • Comprehensive metabolic panel
   • Lipid profile
   • PSA
   • Blood pressure
   • Serum testosterone level

4. Annual comprehensive assessment:

   • All of the above
   • Consider bone density testing if clinically indicated

By following this monitoring protocol, clinicians can optimize the safety and efficacy of combined AndroGel and GLP-2 agonist therapy while minimizing potential adverse effects.