Factors to Consider During Therapeutic Drug Monitoring
1) Timing of Sample Collection of Therapeutic Drug Monitoring:
Steady-State Concentrations: Collect samples once steady-state levels are reached.
Peak and Trough Levels: Measure peak and trough for drugs where timing is critical.
2) Pharmacokinetic Parameters:
Absorption Rate: Affected by food intake and GI motility.
Distribution Volume: Influenced by factors like obesity or edema.
Metabolism: Assess liver function for drugs metabolized by the liver.
Excretion: Renal function tests for drugs cleared by the kidneys.
3) Patient-specific Factors:
Demographics: Age, weight, and gender impact pharmacokinetics.
Genetics: Pharmacogenetics may affect dosing.
Comorbidities: Conditions like diabetes or heart failure alter drug handling.
4) Analytical Considerations:
Assay Accuracy: Reliable methods for measurement.
Matrix Selection: Choosing plasma, serum, or blood samples.
5) Clinical Correlation:
Symptom Assessment: Interpret drug levels with clinical signs.
Therapeutic Goals: Adjust dosing based on clinical outcomes.
6) Drug Formulations and Administration Routes:
Bioavailability Differences: Oral and IV forms vary in absorption.
Sustained-release: Alters timing of peak concentration.
7) Environmental and Lifestyle Factors:
Diet and Nutrition: Foods can impact metabolism.
Substance Use: Alcohol and tobacco affect enzyme activity.