1. Individual Variation in Drug Responses
Chapter 8
Individual Variation in Drug Responses

2. Individual Variation in Drug Responses
Factors that influence drug responses are
Body weight and composition
Age
Gender
Pathophysiology

3. Drug Tolerance
Decreased responsiveness to a drug due to repeated drug administration
Three categories of drug tolerance
Pharmacodynamic
Metabolic
Tachyphylaxis

4. Types of Drug Tolerance
Pharmacodynamic tolerance
Long-term administration
Metabolic tolerance
Accelerated drug metabolism
Tachyphylaxis
Repeated dosing over a short time

5. Bioavailability
Ability of a drug to reach the systemic circulation from its site of administration
Factors that influence bioavailability
Product preparation
Route of administration

6. Failure to Take Medicine as Prescribed
Cooperative and accurate participation in one’s drug therapy
Patient education
Attitude toward taking medications
Self-care capacity
Finances

7. Failure to Take Medicine as Prescribed (cont.)
Drug interactions
Diet