GasGasGas - The FRCA Primary Exam Podcast Gas Gas Gas - Volume of Distribution
Aug 22, 2024
Dive into the intriguing concept of volume of distribution in pharmacology, where drug distribution is explored through fun analogies like shot glasses and bathtubs. Discover how drug properties and patient characteristics influence absorption, and learn the differences between indexed and absolute volumes. Get practical insights on measuring pharmacokinetics, and unravel the behavior of volatile anesthetics in the body. This enlightening discussion will elevate your understanding of drug dynamics in clinical settings.
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Vd Is A Conceptual Volume
- Volume of distribution is a conceptual tool, not a physical reality inside patients.
- It helps predict how drugs 'soak' into different body compartments based on drug and patient properties.
Four Simple Distribution Reservoirs
- Imagine compartments: shot glass (plasma), pint (ECF), bathtub (total body water), reservoir (fat).
- Each drug preferentially occupies one or more of these conceptual reservoirs influencing apparent Vd.
Patient State Alters Drug Distribution
- Patient factors (muscle, fat, age, fluid overload) change how drugs distribute and alter Vd.
- Pathological states like heart, liver, or renal failure can markedly expand distribution spaces.