CADC Alcohol and Drug Counselor Pharmacology of Psychoactive Substances 3 — Questions and Answers
Question 1: Which classification of drugs includes substances like heroin, morphine, and codeine?
- Cannabinoids
- Hallucinogens
- Opioids (Correct answer)
- Dissociatives
Correct answer: Opioids
Heroin, morphine, and codeine are all opioids that act on opioid receptors (mu, kappa, and delta) in the brain and body.
Question 2: A client on buprenorphine maintenance therapy asks why they cannot get high if they use heroin on top of their medication. The best explanation is:
- Buprenorphine metabolizes heroin before it reaches the brain
- Buprenorphine has high opioid receptor affinity and acts as a partial agonist, blocking full agonist effects (Correct answer)
- Buprenorphine permanently damages opioid receptors
- Buprenorphine increases liver enzymes that destroy heroin
Correct answer: Buprenorphine has high opioid receptor affinity and acts as a partial agonist, blocking full agonist effects
Buprenorphine's high receptor affinity and partial agonist activity means it occupies opioid receptors and blocks the effects of additional full agonist opioids.
Question 3: Cross-tolerance between alcohol and benzodiazepines occurs because both substances:
- Are metabolized by the same liver enzyme (CYP2E1)
- Act on the same receptor complex (GABA-A) (Correct answer)
- Release identical amounts of dopamine in the nucleus accumbens
- Have identical molecular structures
Correct answer: Act on the same receptor complex (GABA-A)
Both alcohol and benzodiazepines enhance GABA-A receptor function, so tolerance developed to one substance reduces sensitivity to the other.
Question 4: Which route of administration produces the fastest onset of drug effects?
- Oral ingestion
- Transdermal patch
- Intravenous injection (Correct answer)
- Sublingual absorption
Correct answer: Intravenous injection
Intravenous injection delivers the drug directly into the bloodstream, bypassing all absorption barriers for the fastest onset.
Question 5: Tolerance to a drug most commonly develops because of:
- Permanent destruction of receptors throughout the body
- Pharmacodynamic changes such as receptor downregulation and reduced sensitivity (Correct answer)
- Increased production of competing neurotransmitters
- Improved cardiovascular efficiency that removes the drug faster
Correct answer: Pharmacodynamic changes such as receptor downregulation and reduced sensitivity
Pharmacodynamic tolerance occurs when the nervous system adapts through receptor downregulation and decreased receptor sensitivity with repeated drug use.
Question 6: MDMA (ecstasy) primarily exerts its effects by:
- Blocking NMDA glutamate receptors
- Massively increasing serotonin, dopamine, and norepinephrine release (Correct answer)
- Enhancing GABA-A receptor activity
- Stimulating kappa-opioid receptors
Correct answer: Massively increasing serotonin, dopamine, and norepinephrine release
MDMA causes a massive release of serotonin, dopamine, and norepinephrine while also inhibiting their reuptake, producing euphoria and empathogenic effects.
Question 7: In pharmacology, an antagonist is defined as a substance that:
- Produces effects stronger than the naturally occurring neurotransmitter
- Binds to a receptor without activating it and blocks agonist activity (Correct answer)
- Enhances the effect of another drug when taken simultaneously
- Partially activates a receptor while blocking full agonist activity
Correct answer: Binds to a receptor without activating it and blocks agonist activity
An antagonist binds to a receptor with affinity but has no intrinsic activity, thereby blocking agonists from producing their effects.
CADC Alcohol and Drug Counselor Pharmacology of Psychoactive Substances 3
Which classification of drugs includes substances like heroin, morphine, and codeine?