PSY 356 pharmacokinetics 4

PSY 356 pharmacokinetics 4 - PHARMACOKINETICS CONTINUED...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
PHARMACOKINETICS CONTINUED Time Course of Drug Distribution and Elimination: Concept of Drug Half-Life A. Knowledge about the relationship between the time course of drug action in the body and its pharmacological effects is essential for: a. Predicting the optimal dosage and dose intervals need to reach a therapeutic effect b. Maintaining a therapeutic drug level for the desired period of time c. Determining the time needed to sliminate the drug A. The level of drug in the blood closely approximates the level of the drug at the drug's receptor site of action in the brain B. The half-life tells us how long a drug remains in the body and allows comparison between drugs with similar actions but differing half-lives a. Half-life is the time for the plasm level of drug to fall by 50% and is independent of the absolute level of the drug in blood i. The level falls by 50% every half life regardless of how many molecules of drug were actually metabolized during that time ii. First order elimination -the metabolism rate of the drug is a constant fraction of the drug remaining in the body, rather than a constant amount of drug per hour b. At 98% of the drug eliminated, the person is considered "drug free" c. Even though the blood level of the drug is reduced by 75% after only two half-lives, the
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 05/05/2011 for the course PSY 356 taught by Professor Simson during the Spring '11 term at Miami University.

Page1 / 3

PSY 356 pharmacokinetics 4 - PHARMACOKINETICS CONTINUED...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online