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CoursePsychopharmacology Introduction

The drug-action atlas

Enter through a molecule, a synapse, or a brain circuit. Change the conditions and trace what happens next.

Explore the system

Transform, then eliminate

Follow Phase I and Phase II reactions, and see how enzyme induction and inhibition change the model.

Transform, then eliminate
Parent drug → Phase I → Phase II → Renal eliminationLiverParent drugPhase ICytochrome P450 (CYP) enzymesPhase IIRenal eliminationOften greater water solubility
Baseline enzyme activity

Oxidation · reduction · hydrolysis → Conjugation · glucuronidation

Phases are not a mandatory two-step sequence. Some compounds go directly to conjugation; metabolites can be active. Effects of induction/inhibition depend on the enzyme, parent drug, and metabolites. Many Phase I oxidations involve CYP enzymes; not every Phase I reaction is CYP-mediated.

Illustrative transformation rate: 5

On a small screen, pan the diagram or increase zoom. Named controls provide the same exploration by keyboard.

Predict, then check

Can metabolism produce an active drug rather than only an inactive waste product?

Exploration and predictions are practice. They do not award mastery or XP.

Sources and model limits

Original schematic. Positions show relationships; structures and concentrations are not to scale.

  • Julien's Primer of Drug Action · 15 · 1 · Transform, then eliminate · PDF 15, 16, 17 · 1.8, 1.9