A laboratory can quantify total drug in plasma while struggling to quantify the much smaller unbound portion. That difference can determine whether a pharmacokinetic study answers its question. A result reported as not statistically significant does not resolve the question when the measurements are too limited to detect a meaningful…
Read Article: Total and Unbound Drug Concentrations: What a Fasting Study Could Not Resolve
A medication can be associated with a different drug response because of the condition it was prescribed to treat. That possibility matters when interpreting a concentration-response model as evidence of a pharmacodynamic interaction. Franken and colleagues examined this problem in a study of midazolam sedation in terminally ill adults. Their…
Read Article: Midazolam Sedation Models: Why a Medication Association Does Not Prove Antagonism
A cannabinoid detected after dosing stops is evidence of analytical persistence. It does not, by itself, establish an exact elimination half-life, the time of the last dose or a universal date when another person’s sample will test negative. A controlled study by Wolinsky and colleagues helps explain the distinction. Published…
Read Article: CBD After Repeated Dosing: Why Detectability Does Not Establish a Washout Deadline