Pharmacokinetics Overview

Dosage Form and Pharmacokinetics

• The dosage form of a drug can significantly impact its absorption and bioavailability.

Drug Dosage and Pharmacokinetics

• Drug dosage can influence all pharmacokinetic parameters: absorption, distribution, metabolism, and elimination.

Drug Plasma Concentration

• Plasma concentration of a drug influences its efficacy and potential toxicity.

Drug Half-Life

• The half-life of a drug indicates the time it takes for the concentration of the drug to decrease by half in the body.
• This parameter influences the duration of the drug's action and the required dosing frequency.

ADME Rates

• The rates of absorption, distribution, metabolism, and elimination (ADME) are critical pharmacokinetic parameters.
• They directly influence a drug's efficacy and toxicity.

Peak Plasma Concentration

• The peak plasma concentration of a drug can impact its efficacy and potential toxicity.

Pharmaceutics/Pharmacokinetics

• The primary focus of pharmaceutics and pharmacokinetics is to understand how drugs are absorbed, distributed, metabolized, and excreted (ADME) in the body.

Definition of a Drug

• A drug is a substance intended for use in the diagnosis, mitigation, treatment, cure, or prevention of disease in humans or animals.

Actions of Drugs

• Drugs have diverse actions and effects on the body.

What Pharmacokinetics Studies

• Pharmacokinetics studies the disposition of a drug in the body.

Pharmacokinetic Processes

• The four key processes involved in pharmacokinetics are absorption, distribution, metabolism, and elimination (ADME).

Pharmacokinetic Relationship

• Pharmacokinetics examines the relationship between drug disposition and the response it elicits in the body.

What Pharmacodynamics Studies

• Pharmacodynamics examines the relationship among plasma drug concentrations, time, and pharmacological response.

How Pharmacodynamics Quantifies Drug Influence

• Pharmacodynamics studies the influence of a drug on the body using quantitative analysis, focusing on how drugs interact with cellular components.

Time of Peak Concentration (Tmax)

• Tmax refers to the time at which the maximum concentration of a drug is reached in the body.

Area Under the Curve (AUC)

• AUC is calculated using the trapezoidal rule and represents the total drug exposure over time.
• It is typically expressed in units of mg/mL * hours.

Pharmacokinetics (PK) and Pharmacodynamics (PD)

• Pharmacokinetics (PK) focuses on how drugs move through the body (ADME).
• Pharmacodynamics (PD) focuses on the effects of drugs on the body.

Pharmacokinetic Parameters

• Important pharmacokinetic parameters include:
  • Clearance (Cl)
  • Volume of distribution (Vd)
  • Time of peak concentration (Tmax)

Elimination Rate Constant (Kel)

• The elimination rate constant (Kel) represents the rate at which the drug concentration decreases in the plasma.

One Compartment Model

• Only drugs administered intravenously (IV) meet the criteria for a one-compartment model because IV administration allows for instantaneous distribution into systemic circulation.

Mono-Exponential Pharmacokinetics

• Not all IV drugs exhibit mono-exponential pharmacokinetics.

This quiz covers essential concepts in pharmacokinetics, including drug dosage, half-life, and ADME rates. Understanding these factors is crucial for assessing drug efficacy and safety. Test your knowledge on how dosage forms and plasma concentrations influence pharmacokinetic parameters.