Pharmacokinetics

The fraction of a dose reaching the systemic circulation unchanged

A memory aid for bioavailability and the routes that avoid the liver.

Half-life depends on both clearance and volume of distribution

A memory aid for the relationship between clearance, volume and half-life.

Phase I modifies the molecule; phase II conjugates it

A memory aid for the two phases of drug metabolism.

Km reflects affinity and Vmax reflects capacity

A memory aid for Michaelis-Menten kinetics and enzyme inhibition.

Un-ionised drug is absorbed, so weak acids favour the stomach and weak bases the intestine

A memory aid for how gut pH affects drug absorption.

ADME: Absorption, Distribution, Metabolism, Excretion

A mnemonic for the stages of drug handling.

Reduced metabolism, reduced protein binding and increased sensitivity

A memory aid for adjusting drugs in liver disease.

Reduce the dose or lengthen the interval for renally cleared drugs

A memory aid for adjusting drugs when renal function is reduced.

Only the free fraction is active, and only the free fraction is cleared

A memory aid for why protein binding matters in prescribing.

Filtration of free drug, active secretion, and passive reabsorption depending on pH

A memory aid for how the kidney eliminates drugs.

Enteral routes are convenient; parenteral routes bypass first pass metabolism

A memory aid for the advantages of each route of drug administration.

Narrow therapeutic index drugs where effect cannot be measured directly

A memory aid for which drugs need level monitoring and when to sample.

The theoretical volume needed to contain the dose at the measured plasma concentration

A memory aid for the meaning and use of volume of distribution.

First order clears a constant proportion, zero order a constant amount

A mnemonic for the two patterns of drug elimination.