4. Principles of Drug Abuse Flashcards
1
Q
What is drug abuse?
A
- Use of a drug outside of its medically intended (therapeutic) purpose
2
Q
At what point does ‘drug use’ become ‘drug abuse’?
A
- it depends on…
- individual
- the drug itself
- reason for taking it
- there is a spectrum of psychoactive substance use:
- Beneficial: use that has positive health, spiritual and/or social impacts
- ex. medicinal use as prescribed, moderate consumption of alcohol
- Non-problematic: recreational, casual or other use that has negligible health or social effect
- Problematic: use at an early age or use that begins to have negative impacts for individuals, family/friends or society
- ex. use by minors, impaired driving, binge consumption
- Chronic Dependent: use that has become habitual and cmpulsice despite negative health and social effects
- Beneficial: use that has positive health, spiritual and/or social impacts
3
Q
What is a drug of abuse?
A
- Difficult to characterize in absolute terms
- because they still have therapeutic effects
- Commonly, a drug characterized as (more) likely to be associated with problematic use
- Limited therapeutic benefit, but not always!
- Context-dependent characterization
- ex. Opioid use for pain, or pleasure?
- ex. prescription drugs
- ex. Opioid use for pain, or pleasure?
4
Q
What are 3 important things to note about the relationship between Drug Abuse and Drug of Abuse?
A
- Using a Drug of Abuse need not imply Drug Abuse
- Many Drugs of Abuse have therapeutic benefits
- Drug Abuse is not exclusive to Drugs of Abuse
5
Q
What are the Consequences of drug use?
- hint kinda: Aside from specific pharmacodynamic drug effects, two other processes can occur in the presence of a drug (or, to be more inclusive, substance)
A
- Dependence (“physical dependence”) –> body attempts to produce homeostasis = wants to stay in equilibrium –> tries to revert back to normal. But if the drug is there because you’re chronically taking it, the body will engage in long-term physiological processes to offset these changes
- Progressive physical adaptation to drug use
- Tolerance
- Dependence
- Withdrawal
- Progression and extent depends on drug and conditions of use
- Progressive physical adaptation to drug use
- Substance Use Disorder (“addiction” or “psychological dependence”)
6
Q
What is tolerance?
A
- refers to a reduction in the perceived or demonstrated response of a drug//Reduced response to a drug…
- …following repeated administration
- Acquired tolerance
- acquired: due to drug exposure
- Acquired tolerance
- …compared to the general population
- Innate tolerance
- Innate: is internal to you and usually dependent of genetics
- Innate tolerance
- …following repeated administration
- Acquired tolerance is generally reversible, though dependent on removal of drugs and restoration of underlying biology/physiology
*refer to slide 5 for acquired and innate response graph
7
Q
What are the 2 types of Tolerance?
A
- PK tolerance
- PD tolerance
8
Q
What is PK tolerance?
A
- Alterations in ADME processes, reducing drug plasma concentration
9
Q
What is PD tolerance?
A
- the changes in the cell in terms of adaptation of the drug being present
- no change in plasma [ ] b/c drug isn’t being metabolized to any greater degree
- Adaptive changes within the systems affected by the drug
- ex: Altered receptor expression
- Agonists –> overstimulation –> dec receptor internalization
- (cell feedback aiming to quiet signal)
- Antagonists –> dec stimulation –> inc receptor expression
- (cell feedback seeking expected/regular signal)
- Agonists –> overstimulation –> dec receptor internalization
- ex: Altered receptor expression
10
Q
How can you become more tolerant?
A
- Significant source of drug complications, because:
- A higher dose is required to achieve the desired effect –> potential reduction in specificity
- Not all of a drug’s effects experience tolerance equally
- tolerance is stimulate dependency
- the reason why you’re becoming tolerant is b/c your body has changed b/c of the drug and the body’s attempt to equilibrate those changes
*refer to slide 9 for visual version
11
Q
What is dependence?
A
- State of altered homeostatic mechanisms or equilibria in chronic – or repeated – presence of drug
- Body works “harder” to (partially) compensate/counterbalance pharmacodynamics effects
- Most easily diagnosed by removing the drug in question and looking for an effect
- If the body expects drug to be there = dependent
- equilibrium shifted with new homeostasis = imbalance
- b/c body expects drug to be there = the new normal
*refer to slide 11 for an example
12
Q
What is withdrawal syndrome and what are its 2 major elements?
A
- Imbalance following abrupt cessation of drug until the original “drug-free” homeostatic state can be restored
- 2 major elements
- Rapid removal of the effect of the drug of dependence
- Drug cessation and rapid metabolism/clearance
- Antagonist administration
- Hyperarousal of physiological systems due to drug-induced adaptations, now unopposed
- Rapid removal of the effect of the drug of dependence
- Symptoms vary by drug pharmacodynamics…
- Generally opposite to those normally produced by the drug
- e.g. opioids dilated pupils, tachycardia, etc.
- Generally opposite to those normally produced by the drug
- …and severity heavily influenced by pharmacokinetics
13
Q
Refer to slides 13-15 for long question practice on PK and drug withdrawal.
A
other side!
14
Q
What is substance use disorder?
A
- Progression of dependence beyond biological phenomena into disorder
- More arbitrary in diagnosis compared to tolerance, dependence, and withdrawal
- Condition can prevail long after successfully navigating dependence/withdrawal
- i.e. no more drug in body, but cravings still exist
- Relapses common, even after treatment
- Re-exposure to addictive drug
- Stress
- Contextual cues that recall prior drug use
- Does not occur in all people who use a Drug of Abuse
- continued use despite significant substance-related problems
15
Q
What are the 3 general reasons for abuse/SUD?
A
- Drug-related factors/variables
- Reinforcement
- Mechanism of Action
- Pharmacokinetics
- Factors/variables related to the Individual
- Genetics (polymorphisms affecting drug PD/PK)
- Preexisting Conditions (altered baseline neurophysiology)
- Environmental factors/variables
- how people that use drugs are perceived in their community
- presence of drug
