Drugs of Abuse (Part 2) Flashcards
What are the stimulant drugs?
- Cocaine
- Methamphetamine
- MDMA (ecstasy)
- Nicotine
- Hallucinogens & Dissociative Drugs
Which stimulant drugs structually resemble dopamine & epinephrine?
- Cocaine
- Methamphetamine
- MDMA (ecstasy)
Where is Cocaine derived from?
coca plant
What is the mech of action of Cocaine?
- Blocks reuptake of dopamine
- Also blocks reuptake of norepinephrine and serotonin
- Elevates reward system
- (therefore) Using only ONCE can make someone want to use it again and again
Where is Methamphetamine produced from?
pseudoephedrine and other over-the-counter medicines
What is the mech of action of Methamphetamine?
- Blocks dopamine reuptake, but also increases dopamine release
- Much higher levels of synaptic dopamine than cocaine!!
- Blocks uptake of norepinephrine and serotonin
What does Meth have that’s diff from Cocaine?
Blocks dopamine reuptake (LIKE COCAINE), but ALSO increases dopamine release
Much higher levels of synaptic dopamine than cocaine
What are the Pharmacokinetics of Cocaine?
- Usually snorted, smoked, or injected
- Half life is 1 hr
- 95% is metabolized in liver (CYP2D6), 5% is excreted unchanged in urine
What are the Pharamacokinetics of Meth?
- Usually smoked, snorted, or injected
- Half life is 12 hrs
- 40% is excreted unchanged in urine, the rest is metabolized in the liver to active metabolites (amphetamine)
- Euphoria disappears before drug concentration drops, so users take more to try to maintain the high
What are the short term effects of cocaine & meth?
Dopamine effects: (last 3 @ higher doses)
- Euphoria
- Aggressive behaviour (violence)
- Psychosis (paranoia, hallucinations, etc.)
- Psychomotor agitation (can’t sit still)
Norepinephrine effects:
- Energetic, talkative
- Hyperawareness; Fight or flight
Serotonin effects:
- Mood, loss of appetite, less need for sleep
What can cocaine result in?
- increase sympathetic output & catecholamines can cause ischemia & then infraction resulting in death
- decrease Na transport can cause arrhythmias resulting in death
What are the long term effects of cocaine & meth?
The brain
- Dopamine, norepinephrine, serotonin are depleted
- Excitatory glutamate neurons blunted (particularly in the nucleus accumbens)
- Stress pathways are more sensitive
– Stress leads to more drug seeking behaviour
- Reduced activity in prefrontal cortex
– Poor decision-making, consequences not understood
- Reduced brain glucose metabolism
What are the long term effects of meth (in addition to the ones that are with cocaine & meth)?
- Methamphetamine psychosis
- Severe structural and functional changes in areas associated with emotion and memory
– Possibly permanent (longer than 14 months after abstinence)
What are the long term effects of cocaine & meth?
- Skin sores (crawling insects)
- Weight loss
- Organ toxicity
- Fever
(Dental problems)
What are Cocaine & Meth withdrawal?
- Increased appetite (b/c these drugs are suppressing their appetite)
- Chills, fatigue
- Anxiety, depression, insomnia
- Muscle aches
- Tremors
- Meth withdrawal lasts longer (usually at least 3 weeks)
- Antidepressants, antipsychotics, dopamine agonists (D2 receptors) are currently being investigated as treatment options
What is MDMA (Ecstasy)?
- N-methyl-3,4 methylenedioxymethamphetamine
- Structurally similar to amphetamines, but also similar to hallucinogen mescaline
What is the mech of action of MDMA (Ecstasy)?
- Blocks reuptake of serotonin and norepinephrine
- WEAKLY blocks reuptake of dopamine (less association with addiction)
What is the route of admin of MDMA?
- Oral tablet or capsule
- 45 min to feel effects, high usually lasts 3-4 hours
- Half life 5-7 hours
What is the metabolism of MDMA?
- Metabolized in liver by CYP2D6 (like cocaine)
- However, other enzymes are involved and they are saturated at relatively low concentrations
– Small changes in dosage can greatly increase the risk of toxicity. - ELIMINATION IS SLOW
- 40 hours for 95% of the drug to be cleared
What are the short term effects of MDMA?
- Well-being, stimulation, distortions in time and sensory perception, and enhance enjoyment from sensory experiences
- Increases empathy
called the empathetic drug
Serotonin effects:
- Mood-elevation, empathy
Norepinephrine effects:
- Energetic, talkative
- Hyperawareness; Fight or flight
Dopamine effects:
- Euphoria
What can MDMA cause?
Amphetamine-like side effects on other organs (mostly b/c increase NE)
Overdose can cause:
- Hypertension
- Faintness
- Panic attacks
- Seizures
- Loss of consciousness
- *Hyperthermia- deadly in warm environments (#1 risk)
What are the long term effects of MDMA?
Serotonin is depleted leading to negative psychological effects for several days after use
–> Depression, sleep disturbances, etc.
- Dental problems
- Lack of appetite
What happens with heavy use of MDMA?
- Serotonin neurons become damaged
- Decreased brain activity
What is Nicotine?
Active ingredient in tobacco
What is the mech of action of Nicotine?
- Binds nicotinic acetylcholine receptors (are ion channel receptors)
- Mimics acetylcholine, causes cell depolarization
- Activates adrenal gland to release epinephrine
- Activates nicotinic receptors on dopaminergic neurons in the reward pathway
- Transient surge in endorphins that causes a brief, weak euphoria
What are the Pharmacokinetics of Nicotine?
- Half life is 1 hr
- Dissipates quickly along with positive feelings, driving frequent using
- 70% of nicotine is metabolized to cotinine
- Cotinine
– Long half life (20-30 hrs)
– Some brain effects (decreases anxiety, enhances memory)
What are the short term effects of nicotine & smoking?
- “Kick”
- Appetite suppression
- Short term memory enhancement
- Irritability, dizziness, abnormal dreams
- Increased heart rate and blood pressure
- Muscle tremors/pain
- Bronchospasms
- Nausea, diarrhea, dry mouth
What is the long term effects of Nicotine?
The prefrontal cortex is altered
- In young people this might be permanent (b/c prefrontal cortex is still developing until 20)
- Difficulty paying attention
- Decision making
- Impulse control
How is nicotine addition treated?
Nicotine withdrawal
- Irritability, cravings, cognitive deficits, sleep disturbances, increased appetite
Nicotine replacement therapy
- Patch, chewing gum, etc.
- Varenicline
– Blocks specific nicotinic receptors in the mesolimbic system
– No rewarding feelings when smoking
What are the Classic Hallucinogens?
- LSD (d-lysergic acid diethylamide, aka: acid)
- Psilocybin (mushrooms)
- Peyote (mescaline)
What are the Dissociative Drugs?
PCP
What is the Classic Hallucinogens mech. of action?
- Activate 5-HT2 serotonin receptors
- 5-HT activation increases glutamate pathways
- At high doses, modest influence on dopamine pathways
Not entirely clear how this causes hallucinations
What is the route of admin. of LSD?
- Paper soaked in LSD, placed on the tongue
- Tablets or diluted in drinks
What are the Pharmacokinetics of LSD?
Most potent hallucinogen
- Rapidly metabolized in the liver to inactive metabolites
- Effects last up to 12 hours (b/c brain chemistry is altered)
(even though the drug isn’t in system it still has effects)
Which hallucinogen is the MOST potent?
LSD
What are the Pharmacokinetics of Psilocybin (mushrooms)?
Mushrooms- dried or raw, steeped in tea
- Significant hallucinations up to 1hr
- Effects last up to 8 hours
- Dephosphorylated to active metabolite PSILOCIN
- 80% of psilocin is glucuronidated and excreted in the urine
- Remainder is metabolized in liver
What are the short term effects of Hallucinogens?
Profound distortions in a person’s perceptions of reality
- See images, hear sounds, and feel sensations that don’t exist
Emotions swing widely
Autonomic system is activated
- Increased heart rate
- Increased blood pressure
What are the 2 diff. effects of Hallucinogens characterized as?
“Good trip”
- Mentally stimulating and feelings of a heightened understanding
“Bad trip”
- Terrifying thoughts and nightmarish feelings of anxiety and despair that include feelings of losing control, insanity, or death
Which Hallucinogen are BAD trips more common in? & what does it also cause?
LSD
b/c LSD is MOST potent
LSD also causes “flashbacks” that occur up to years after taking the drug
What is general about the effects of Hallucinogens?
Generally NO evidence of organ toxicity
However, extreme LSD use can lead to long-term psychosis
What is Phencyclidine (PCP)?
Dissociative anesthetic and analgesic
What is the mech. of action for Phencyclidine (PCP)?
- HIGHEST AFFINITY: inhibits NMDA receptors (glutamate ion channels)
- Inhibits dopamine, norepinephrine, and serotonin reuptake (risk of addiction)
- Increases dopamine and norepinephrine production
- LOWEST AFFINITY: activates opioid receptors
What is the route of admin. for PCP?
Can be SMOKED, snorted, ingested, or injected
What are the Pharmacokinetics of PCP?
- 90% metabolized by oxidative hydroxylation in liver
- Effects last 6-24 hours (lasts v. long)
PCP is fat soluble and effects can linger in people with more body fat
- up to 48 hours or come and go over days (as its released from body fat)
What are the short term effects of PCP at LOW doses?
- Alternate between lethargy and fearful agitation
- Violent behaviour
- Nystagmus (involuntary eye movements)
- Tachycardia
- Hypertension
- Drunk/euphoric
- Analgesia
What are the short term effects of PCP at MODERATE - HIGH doses?
- Acute schizophrenia: psychosis, hallucinations, paranoid delusions
- Cardiac arrythmias
- Coma
Why does Acute Schizophrenia occur due to PCP at MODERATE - HIGH doses?
b/c of the NMDA receptor inhibition
What are the long term effects of PCP?
- Prolonged psychosis that may develop into schizophrenia
- Flashbacks (like LSD; even years later)
- Persistent speech problems
- Severe depression
- *Significant likelihood of self-inflicted trauma due to violent behaviour combined with analgesic effects of drug (they don’t feel pain so are more likely to injure themselves)
Which drugs cause the greatest euphoria (most addictive)?
- Opioids
- ~Alcohol
- Cocaine
- Meth
- Nicotine
- PCP
Which drugs cause nasty withdrawal symptoms?
- Opioids
- Alcohol
- Cocaine
- Meth
Which drugs cause permanent neuronal damage or death?
- Inhalants
- Cocaine
- Meth
- MDMA
- ~Nicotine
Which drugs cause organ toxicity?
- Opioids
- Alcohol
- Inhalants
- Cocaine
- Meth
- MDMA
- Nicotine