Tolerance and Dependence

Question 1

Drug dependence NIDA definition

National Institute of Drug Abuse

Answer 1

In the case of heroin, dependence forms when neurons adapt to repeated exposure and only function normally in the presence of the drug

Question 2

Drug tolerance explanation

Answer 2

Develops typically over days or weeks

Gradual decrease in the responsiveness to a drug

Question 3

Four consequences of drug tolerance

Answer 3

Change in receptors

Exhaustion of mediators

Physiological adaptation

Increased metabolic degradation of the drug

Question 4

Explain in detail enzymatic induction in drug tolerance

Answer 4

Metabolising enzymes in the liver can undergo induction

Induction is caused by either synthesis or reduced breakdown of metabolic enzymes

Question 5

List the five consequences of enzyme induction in drug tolerance

Answer 5

Results in faster metabolism and elimination of the drug

Enzymes subject to induction include the Cytochrome P450 system, microsomal oxidase and conjugating systems

Question 6

State the individual consequence of drug tolerance

Answer 6

A person who develops drug tolerance will need to take larger doses to get the same effect of the drug

Question 7

List the three common drugs which display strong tolerance

Answer 7

Morphine
Barbiturates
Ethanol