Can One Olanzapine Plasma Result Predict an Individual’s Clinical Response?
A concentration-response study in first-episode psychosis explored whether one plasma sample could help identify clinical response to olanzapine. Its sampling schedule and classification performance matter to that question.
What the pilot measured
The study included 23 adherent patients receiving olanzapine alone. Samples were drawn about 11 hours after dosing, two months into treatment. The researchers examined clinical response and adverse-effect scales. Some concentration measures were associated with psychotic-symptom response, but the proposed breakpoints produced many false positives because specificity was insufficient.
What to establish before using a threshold
A group association does not make a concentration a reliable individual classifier. Collection time, prescribed dose, adherence and factors such as smoking can affect interpretation. The study does not provide a validated rule that one plasma value establishes effectiveness, adverse effects or functioning at a different time.
Source
Zabala et al., Journal of Clinical Psychopharmacology · Full text
