Test 4: Drugs of Abuse pt 2 Flashcards
What kind of drug is Methamphetamine?
-Class 3: Dopamine Transporter
-Synthetic INDIRECT Sympathomimetic
-Works on release of the NTs
-Impacts amount of circulating catechols
-Highly lipophillic
-Onset route dependent (Instant – 30 min)
-DOA: 4-8 hours
-Metabolized in liver & excreted by the kidney
-Neurotoxic (antagonist) to the NMDA receptor
-Tolerance develops quickly, resulting in dose escalation with chronic use.
-5/5 on addiction scale
What is the MOA of Methamphetamine?
-Dopamine transporter is reversed, so more dopamine is exiting the presynaptic membrane.
-Blocks VMAT so that Dopamine cannot be placed into the vesicles
-Dopamine stays floating in the presynaptic membrane, so by concentration gradient, it is released into the synapse
-Results in increased circulating dopamine.
How does Methamphetamine cause different characteristics?
By working on different catecholamines.
-Impact on dopamine seems to be larger, but does hit NE and 5HT3 as well
What are the Dopamine effects of Methamphetamine?
Effects are more aggressive on dopamine than other catecholamines.
-Euphoria
-Abnormal movements
-Psychotic episodes
What are the Norepi effects of Methamphetamine?
Increase arousal
Reduce sleep
Tachycardia
HTN
What are the Serotonin effects of Methamphetamine?
Hallucinations
Anorexia
Hyperthermia
What are withdrawal symptoms of methamphetamine?
Dysphoria
Drowsiness
Insomnia (some cases)
General irritability
Why does teeth decay occur with methamphetamine use?
Due to SNS stimulation = dry mouth.
-Airway hazard.
What is Amphetamine psychosis?
Psychosis can happen with acute or chronic use of crystal meth. Hyperstimulation of SNS.
-Visual & Auditory Hallucinations
-Paranoia
-Self-absorption
-Irritability
-Aggressive & erratic behavior
-Picking at skin
-Insomnia
What kind of drug is Cocaine?
-Class 3 (Dopamine Transporter). Has greater effects on NE than meth.
-Water soluble salt stimulant of the SNS
-Highly addictive (5/5)
-Injected or absorbed by any mucous membrane
-Smoked for instant onset “rush”
Onset/Duration
-Smoking: 6-8 sec. for 20 min.
-IV: 15 sec. for 30-60 min.
-Nasal: 5 min. for 90 min.
How was cocaine used in medicine?
-Local anesthetic
-Dilate pupils in opthamology
-Freud tried to use it to treat depression and alcohol dependence but its high rate of addiction was counterproductive
What is the “cycle” of cocaine use?
Use is cyclical:
-Use
-Euphoria
-Depression
-Craving
Dependence and addiction may develop after only a few uses.
What effects occur with chronic use of cocaine?
Loss of appetite
Hyperactivity
Insomnia
Increased risk for intracranial hemorrhage, ischemic stroke, MI and seizures
OD = hyperthermia, coma, and death
What are withdrawal symptoms of Cocaine?
Similar to but not as strong as that of opioids
-Dysphoria, sweating
-Nausea, vomiting, diarrhea
-Muscle aches, fever
-Lacrimation, rhinorrhea, mydriasis
-Piloerection
-Yawning
How is cocaine metabolized?
-90% by plasma cholinesterases to 2 inactive metabolites
-10% by liver cholinesterases to norcocaine (active)
-Half-life 30-90 min depending on route of administration
Metabolism is so rapid that patient in OR being acutely intoxicated is unlikely.
What are the limits associated with a Urine Drug Screen?
-Document the indications for the test
-Have a plan in place of what to do if the results are positive prior to ordering
-Limited test: Possibility of a false positive; May not detect fentanyl or methadone use
-Negative test does not mean that the patient will not be acutely intoxicated in the OR (Patient may use prior to transfer to the OR)
How long will cocaine metabolites appear in a UDS?
-6 days after a single dose
-10-20 days after high dose, long term use
What is the MOA of Cocaine?
Peripheral: Inhibits voltage gated Na channels
Central:
-Cocaine inhibits the dopamine transporter (DAT), decreasing DA clearance from the synaptic cleft and causing an increase in extracellular DA concentration.
-Blocks reuptake of Dopa, 5HT, and NE
-Increases Dopamine at the Nucleus Accumbens
-Inc NE > inc Dopamine
What are the results of the increased NE associated with cocaine?
-acute ↑ in arterial pressure, tachycardia, and ventricular arrhythmias.
-Increases in NE agonize SNS. HTN, tachycardia, arrhythmias. Problem for anesthesia.
What are the differences between methamphetamine and cocaine?
Cocaine blocks Dopa transporter, so you don’t have dopa reuptake back into presynaptic side of neuron.
-Have more Dopa in circulation
-Does same actions on NE as well. More NE floating around.
Meth:
-Affects the Vesicular transport as well.
What is a “Speedball”?
-IV cocaine mixed with heroin
-Stimulant + Depressant
Counter the side effects of both drugs
-Pharmaceutical Opioids
-Benzodiazepines
-Barbiturates
What kind of drug is Methylene-dioxymethamphetamine (MDMA)?
Amphetamine derivative AKA Molly AKA Ecstasy AKA X
-Fosters feelings of intimacy and empathy without impairing intellectual capacity
-Reverses monoamine transporters: 5-HT Transporter (SERT). No reuptake of 5HT. Can reduce 5HT stores with chronic use.
-Onset 30 min lasting 3-5 hrs
-Marked intracellular decrease of 5-HT for 24 hours after 1 dose (Potentially permanent with chronic use; Neurotoxic)
-Acute effects: hyperthermia & dehydration
-Addiction potential is unknown
-Works on 5HT > Dopa
-Metabolism: Liver to active metabolites
What is Serotonin Syndrome?
Too much serotonin.
-Mental status change
-Autonomic hyperactivity
-Neuromuscular abnormalities
-Seizures
Why can MDMA lead to water intoxication?
Effects of MDMA are hyperthermia & dehydration. Users hydrate during use. Can lead to water intoxication:
-Severe hyponatremia
-Seizure
-Death
What are the withdrawal symptoms of MDMA?
-“Offset” mood – depression lasting possibly several weeks
-Aggression during periods of abstinence in chronic users
Substance Abuse/Substance Use Disorders (SUD) are associated with what negative healthcare characteristics?
-A high rate of unplanned admissions or readmissions within 30 days
-Refractory pain
-Decreased functional status
-Increased length of stay
-Increased readmission rates
-Increases economic cost
What are indicators/clues to substance abuse?
-Refuses provider permission to obtain old records
-Reluctance to undergo a urine drug screen (UDS)
-Multiple allergies to recommended medications
-Requests for a specific drug
How should you discuss drug use with patients?
-Use professional open-ended questions
-Make a point to be non-judgmental
-Potential educational opportunity
-Adverse effects of substance abuse
-Impact of illicit substances on anesthetic care
