PODA: Substance Abuse Flashcards
_________ is produced when there is a progressive pharmacological ADAPTATION to the drug resulting in tolerance
Dependence or physical dependence
This can be considered a form of MALADAPTIVE MEMORY….It is produced by REPEATED DRUG USE and leads progressively to compulsive out of control drug use
Addiction
Drug addiction causes brain reward circuits
TorF: most users with addiction potential do not develop a drug use disorder?
True
The likelihood of a person who uses drugs developing a substance abuse disorder depends on three things:
- The drug variables
- The Host variables
- The environment
THIS is defined as the ability of a drug to produce effects that will make the user want the drug again
REINFORCEMENT
Reinforcing properties of drugs are linked to their capacity to …
INCREASE neuronal activity in the brain REWARD AREAS
mesolimbic DA pathway
Cocaine, amphetamine, ethanol, opioids, cannabinoids, and nicotine INCREASE DA levels in the:
VENTRAL STRIATUM
specifically in the nucleus accumbens which causes euphoria
What factors affect drug variables?
- Speed and onset
- Availability
- Cost
- Purity/potency
- Route of administration
HOST variables that affects likelihood of substance abuse?
- Hereditary
- Metabolism of drugs
- Psychiatric symptoms
- Prior experiences or expectations
- Propensity for risk taking behaviors
Repeated dosing of a drug leads to a RIGHTWARD SHIFT in the dose-response curve can be defined as:
Acquired tolerance
This is acquired pharmacoKINETIC tolerance:
develops when the capacity to METABOLIZE or EXCRETE a drug INCREASES
Pharmacodynamic tolerance
this is due to NEURONAL ADAPTATION leading to REDUCE RESPONSE to the same concentration of drug
short term exposure vs long term exposure to drugs:
Short term: neuroadaptive changes in NT release due to DECREASE in receptor number or altered conductance of ion channels
Long term: neuroadaptive changes in GENE EXPRESSION relating to learning and memory
The need for a drug to be present at the site of action to maintain normal functioning
Dependence
What are the MOAs of ethanol?
- Increases Cl- conductance through GABAA receptors leading to hyperpolarization
- DECREASES Ca+2 conductance via NMDA receptors leading to hyperpolarization
MOLECULAR adaptation to chronic alcohol intake involves these mechanisms:
- Internalization and decreased expression of normal a1 subunit on GABAA receptors
- Increased surface expression of low sensitivity a4 subunits on GABAA receptors
- Increased phosphorylation of NMDA receptors containing high conductance NR2B subunits
During withdrawal, when the patient is in a dependent state, in the absence of alcohol, neuronal adaptation can lead to:
Generalized hyperexcitability of neurons
CNS excitation is demonstrated as anxiety, insomnia, delirium, and possibly seizures
TorF: rewarding effects of alcohol may be partially mediated by a direct action on cannabinoid receptors.
FALSE. rewarding effects of alcohol may be partially mediated by an INDIRECT action on cannabinoid receptors.
SE of Antabuse incl:
- Optic and PERIPHERAL NEUROPATHY
- drowsiness
- rash
- psychosis
- hepatitis(RARE)
- metallic taste
GIWA’s PP: (causes severe nausea, vomiting, flushing when consumed with alcohol which essentially requires strict abstinence from all alcohol)
MOA of Antabuse:
inhibits aldehyde dehydrogenase=increased acetaldehyde in the blood=producing an acute sensitivity to ethanol
Naltrexone:
- Opioid receptor antagonists that blocks endorphin activation properties of alcohol
- BETTER TOLERATED THAN DISULFIRAM
- SE: hepatotoxicity, nausea, insomnia
Acamprosate:
- competitive inhibitor of glutamate receptors and (GIWA): possibly inhibit GABA
- normalizes dysregulated neurotransmission associated with chronic alcohol intake
SE: GI upset, muscle or joint pain, headache, syncope, impotence, edema, palpitations, (GIWA): NAUSEA AND DIARHHEA
Chronic administration of BZD can induce DOWN-REGULATION of these pathways by neuroadaptation:
DOWN-REGULATION may be due to:
- uncoupling of BZD site from GABAA receptors
- CHRONIC ADMINISTRATION…down-regulation can leave the brain under-inhibited therefore increasing the possibility of seizures and delirium after abrupt withdrawal of BZD
The rewarding and addicting effects of BZD are presumed to be mediated by
a1 containing GABAA receptors expressed on neurons in the VTA