Drugs do not saturate tissues within the body at the same rate. They are quickly absorbed into blood plasma and into well-perfused organs. Muscle, fat, and bone are saturated last. These tissues can serve as storage depots for substances, contributing to the half-life of a drug and potentially to interaction effects days or weeks after a drug has been discontinued.
The body may be inappropriately treated as a single entity or compartment. In a single-compartment model, drugs are theoretically presumed to diffuse through tissues and the differences in absorption and retention of a drug are not treated as significant. This single-compartment model is sufficient in many situations but is less useful when drugs may be preferentially retained in one type of tissue. Dosage predictions fail if they do not account for the gradual ambient leaching of the drug from fat or bone into general circulation.
The instances in which a multicompartment model is most relevant are for...
References and Readings
- Brunton, L. B., Lazo, J. S., & Parker, K. L. (Eds.). (2005). Goodman & Gilman’s the pharmacological basis of therapeutics (11th ed.). New York: McGraw Hill.Google Scholar
- Stahl, S. M. (2008). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications. New York: Cambridge University Press.Google Scholar