Lecture 15: Addiction pharmacotherapy Flashcards
Characteristics of addiction
Inability to consistently Abstain
Impairment in Behavioral control
Craving; or increased “hunger” for drugs or rewarding experiences;
Diminished recognition of significant problems with one’s behaviors and
interpersonal relationships; and
A dysfunctional Emotional response
Diagnostic criteria for DSM V opioid use disorder
A problematic pattern of opioid use leading to clinically significant impairment or distress, as manifested by at least two of the 11 criteria, occurring within a 12-month period.
How to distinguish between mild, moderate and severe opioid use disorder (DSM V)
Mild: Presence of 2–3 symptoms.
Moderate: Presence of 4–5 symptoms.
Severe: Presence of 6 or more symptoms.
Other characteristics of opioid abuse
- Opioids are often taken in larger amounts or over a longer period than was intended.
- There is a persistent desire or unsuccessful efforts to cut down or control opioid use.
- A great deal of time is spent in activities necessary to obtain the opioid, use the opioid, or recover from its effects.
- Craving, or a strong desire or urge to use opioids.
- Recurrent opioid use resulting in a failure to fulfill major role obligations at work, school, or home.
- Continued opioid use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of opioids.
- Important social, occupational, or recreational activities are given up or reduced because of opioid use.
- Recurrent opioid use in situations in which it is physically hazardous.
- Continued opioid use despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by the substance.
- Tolerance
- Withdrawal
What is tolerance?
A need for markedly increased amounts of opioids to achieve intoxication or desired effect.
A markedly diminished effect with continued use of the same amount of an opioid.
What is withdrawal?
The characteristic opioid withdrawal syndrome (refer to Criteria A and B of the criteria set for opioid withdrawal, pp. 547–548).
Opioids (or a closely related substance) are taken to relieve or avoid withdrawal symptoms.
What is the harm reduction philosophy?
Harm reduction attempts to decrease the harmful consequences of illicit drug use to the individual, family, community and society.
The goals of the program are to reduce illicit opioid use, needle sharing, criminal activity and mortality associated with addiction.
What are the pharmacotherapy options for opioid use disorder?
Methadone
Buprenorphine/naloxone or buprenorphine alone
Methadone structure
Synthetic opioid
Structurally unrelated to opiates
See figure
What receptors does methadone target?
Agonist at the μ-opioid receptor
NMDA antagonist
Uses of methadone
analgesia and withdrawal management in
opioid dependent individuals
No rush/euphoria in stabilized patients
Blocks euphoria from heroin and other opioids
Duration of action of methadone and dosing
Long duration of action
allows once daily dosing in methadone maintenance therapy (MMT)
Why does methadone have a street value?
Keeps people out of withdrawal when they can’t get the opioids they want (treats “junk sickness”)
Absorption of methadone
Following oral dosing methadone is detected in the plasma within about 30 minutes
Peak plasma levels 2-4 hours after ingestion
PO bioavailability is 90 %
Distribution of methadone - VD, t1/2, steady state, withdrawal suppression
Highly protein bound to both plasma proteins and tissue proteins
VD (volume of distribution) = 4-5L/kg
t1⁄2 = 22 hours (15-40 hours)
5-7 days to reach steady state with repeated dosing
Withdrawal typically suppressed for 24-36 hours with therapeutic doses
Metabolism of methadone
Primarily metabolized by cytochrome P450 3A4 to the inactive metabolite EDDP
Also metabolized to a lesser extent by CYP 1A2, 2B6, 2C8, 2C9, 2C19, and 2D6
Weak inhibitor of 2D6
