Pharmacology: Pharmacokinetics and Drug Elimination

Front

Drug elimination includes the processes of metabolism and excretion.

Back

What is drug elimination?

Front

Metabolism is the process by which the structure of a drug is altered to decrease its biological activity and facilitate its excretion.

Back

What is metabolism in the context of drug elimination?

Front

Excretion is the process by which drug and drug metabolites are removed from the body.

Back

What is excretion in drug elimination?

Front

Phase I involves alteration of the drug, while Phase II involves conjugation.

Back

What are the two phases of drug metabolism?

Front

1. Reduced biological activity (inactivated) 2. Alteration in biological activity (still active) 3. Increased or activated biological activity (activation of a pro-drug or production of an active metabolite).

Back

What are potential outcomes of drug metabolism?

Front

Induction is when a drug or compound induces increased synthesis of a metabolic enzyme, leading to increased enzyme activity.

Back

What is microsomal induction?

Front

Inhibition is when a drug or compound inhibits the activity of a metabolic enzyme, leading to decreased enzyme activity.

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What is microsomal inhibition?

Front

1. Species (e.g., cats have reduced ability to metabolize certain drugs) 2. Age (young and old animals have reduced enzyme production) 3. Disease processes (malnourished animals and those with liver disease have less protein and reduced enzyme levels).

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What factors can affect drug metabolism?

Front

1. Kidneys (majority) 2. Liver (bile) 3. Intestinal tract 4. Mammary glands 5. Salivary glands and skin.

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What organs are involved in drug excretion?

Front

The biological half-life is the time required for the concentration of a drug in the systemic circulation to decrease by one half of its initial value.

Back

What is the biological half-life (T1/2) of a drug?