SUBJECT AREA · 10 GUIDES
Pharmacology & Interpretation
Absorption, distribution, metabolism, elimination, timing, effects, and evidentiary limits.
EVIDENCE REVIEW
How to interpret concentration, timing, and effect
Pharmacology connects a laboratory result to absorption, distribution, metabolism, and elimination, but the connection is rarely one-to-one. Interpretation should account for the tested matrix, collection time, active drug and metabolites, dose history when known, route of administration, tolerance, medical condition, drug interactions, and the uncertainty associated with the method. Population ranges can provide context, but they are not automatic boundaries between therapeutic use, toxicity, impairment, or death.
A careful opinion states which conclusions are directly supported by the measurement and which depend on assumptions or missing facts. Concentration alone may not establish when a substance was used, the dose taken, observed behavior, or the role of the substance in an event. These guides organize the scientific questions that should be addressed before pharmacological evidence is presented in litigation.
Pharmacogenetics and Toxicology
Genetic variation can influence drug metabolism, but genotype alone rarely reconstructs dose, timing, adherence, interactions, or clinical effect.
Therapeutic Drug Monitoring
Therapeutic drug monitoring uses timed concentrations to support dosing decisions. Forensic use requires knowing sampling time, dose history, clinical purpose, and matrix.
Detection Windows
A detection window is an estimate shaped by dose, frequency, metabolism, specimen, cutoff, and method sensitivity. It is not a universal timetable.
Pharmacokinetics in Toxicology
Pharmacokinetics describes how drug concentrations change through absorption, distribution, metabolism, and elimination. Population models do not reconstruct an individual with certainty.
Drug Absorption
Absorption moves a drug from the administration site into systemic circulation. Route, formulation, food, physiology, and co-exposures affect its rate and extent.
Drug Distribution
Distribution moves drugs among blood and tissues. Protein binding, lipophilicity, perfusion, and tissue affinity influence measured concentrations.
Drug Metabolism
Metabolism transforms drugs through enzymes and other pathways. Products may be active, inactive, toxic, shared with other drugs, or altered by interactions.
Drug Elimination
Elimination removes parent drug and metabolites through renal, biliary, pulmonary, and other routes. Disease and interactions can change clearance.
Drug Half-Life
Half-life is the time for a concentration to fall by half under specified conditions. Published values are ranges and should not be treated as individual clocks.
Drug Interactions
Drugs can interact through metabolism, transport, receptors, physiology, or additive effects. Detecting two compounds does not automatically establish a clinically meaningful interaction.
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