Drugs of Abuse Flashcards
What is Drug Abuse?
• Abuse is the excessive self-administration of
any substance for nonmedical purposes.
• Some drugs of abuse do not lead to addiction.
• This is the case of substances that alter
perception without causing sensations of reward
and euphoria, such as the hallucinogens.
What behaviors indicate addiction?
Behaviors that include one or more of the following: • impaired control over drug use • compulsive use • continued use despite harm • craving
What is physical dependence and how can withdrawal syndrome be reproduced?
• State of adaptation manifested by drug class
specific withdrawal syndrome.
• The withdrawal syndrome can be produced by:
• abrupt cessation
• rapid dose reduction
• administration of an antagonist.
What is withdrawal syndrome?
• Physiological and behavioral changes directly
related to sudden cessation or reduction in use of a drug to which the body has become adapted.
What is considered tolerance?
• A state of adaptation in which exposure to a
drug induces changes that result in a diminution
of one or more of the drug’s effects over time.
• Tolerance may occur to both the desired and
undesired effects of drugs, and may develop at
different rates for different effects.
Physical dependence and Tolerance
• Normal responses that often occur with the
persistent use of certain medications.
Mechanisms of Addiction?
• The mesolimbic dopamine system is the prime
target of addictive drugs.
• As a general rule, all addictive drugs activate
the mesolimbic dopamine system.
Types of drugs of abuse?
- CNS DEPRESSANTS
- PSYCHOSTIMULANTS
- NICOTINE
- OPIOIDS
- MARIJUANA
- PSYCHEDELIC AGENTS
- INHALANTS
- ANABOLIC STEROIDS
list 3 cns depressants?
- Ethanol
- Benzodiazepines
- Barbiturates
Ethanol classification and moa?
• Ethanol is classed as a depressant because it
produces sedation and sleep.
• The initial effects of ethanol are often perceived
as stimulation due to suppression of inhibitory
systems.
• Ethanol influences several cellular functions:
• GABAA receptors
• Kir3/GIRK channels
• Adenosine reuptake
• Glycine receptors
• NMDA receptors
• 5-HT3 receptors.
Describe ethanol withdrawal syndrome?
• Heavy consumption of ethanol leads to acquired
tolerance and physical dependence.
• Withdrawal syndrome may include tremor, nausea, vomiting, sweating, agitation and anxiety.
• This may be followed by hallucinations.
• Generalized seizures may appear after 24-48 h.
• After 48-72 h delirium tremens may appear.
• Delirium tremens is associated with 5-15%
mortality.
TREATMENT OF ALCOHOL WITHDRAWAL?
• Long half-life benzodiazepines are the preferred agents: Diazepam and chlordiazepoxide.
• Because of their long half-life, withdrawal is smoother, and rebound withdrawal symptoms are less likely.
• Lorazepam and oxazepam are intermediateacting drugs.
• They may be preferable in the elderly and
those with liver failure.
Treatment of alcohol addiction?
• Three drugs are FDA-approved for treatment of alcoholism: • Disulfiram: Aldehyde dehydrogenase inhibitor. Used to create aversion to drinking. • Naltrexone: Orally available opioid antagonist. Reduces craving for alcohol. • Acamprosate: NMDA receptor antagonist. Prevents relapse. Topiramate • Facilitates GABA function, antagonizes glutamate receptors. • May reduce cravings. • Not FDA-approved.
Benzodiazepine overview, withdrawal syndrome, and management of withdrawal?
• Can cause physical dependence and addiction.
• Addiction is rare.
• Signs and symptoms include: tremors, anxiety,
perceptual disturbances, dysphoria, psychosis,
and seizures.
• The syndrome can be life-threatening.
• If the patient is on a short-acting drug, they are
switched to a long-acting drug.
• Diazepam is the most used agent.
• Then the dose is gradually reduced.
What does barbiturate abuse resemble?
• Abuse problems with barbiturates resemble those seen with benzodiazepines.
List three psychostimulants?
- Methylxanthines
- Cocaine
- Amphetamines
List 3 methylxanthines and moa?
• Caffeine, theophylline & theobromine.
• Caffeine is the most widely consumed stimulant.
• Methylxanthines block presynaptic adenosine
receptors.
• Activation of adenosine receptors inhibits
norepinephrine release.
• Therefore blockade of adenosine receptors
increases norepinephrine release.
Actions of caffeine dose on CNS?
CNS
• 100–200 mg caffeine (1 - 2 cups of coffee) cause decrease in fatigue and increased mental
alertness.
• 1.5 g caffeine (12 to 15 cups of coffee) produces
anxiety and tremors.
• The spinal cord is stimulated only by very high
doses (2–5 g) of caffeine.
METHYLXANTHINES:
TOLERANCE AND WITHDRAWAL
• Tolerance can rapidly develop to the stimulating
properties of caffeine.
• Withdrawal consists of feelings of fatigue and
sedation.
• Addiction is rare.
• Caffeine is not listed in the category of addicting
stimulants.
Cocaine overview and moa?
• Due to its abuse potential, cocaine is classified
as a Schedule II drug by the DEA.
• Cocaine inhibits dopamine, norepinephrine and
serotonin reuptake.
• The prolongation of dopaminergic effects in the
brain’s limbic system produces the intense
euphoria that cocaine initially causes.
Cocaine’s action on the cns?
CNS
• Stimulation of cortex and brainstem.
• Increases mental awareness and produces a
feeling of well-being and euphoria.
• Paranoia may occur after repeated doses.
• At high doses: tremors and convulsions, followed by respiratory and vasomotor
depression
