Test 4: Drugs of Abuse pt 2

Question 1

What kind of drug is Methamphetamine?

Answer 1

-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

Question 2

What is the MOA of Methamphetamine?

Answer 2

-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.

Question 3

How does Methamphetamine cause different characteristics?

Answer 3

By working on different catecholamines.
-Impact on dopamine seems to be larger, but does hit NE and 5HT3 as well

Question 4

What are the Dopamine effects of Methamphetamine?

Answer 4

Effects are more aggressive on dopamine than other catecholamines.
-Euphoria
-Abnormal movements
-Psychotic episodes

Question 5

What are the Norepi effects of Methamphetamine?

Answer 5

Increase arousal
Reduce sleep
Tachycardia
HTN

Question 6

What are the Serotonin effects of Methamphetamine?

Answer 6

Hallucinations
Anorexia
Hyperthermia

Question 7

What are withdrawal symptoms of methamphetamine?

Answer 7

Dysphoria
Drowsiness
Insomnia (some cases)
General irritability

Question 8

Why does teeth decay occur with methamphetamine use?

Answer 8

Due to SNS stimulation = dry mouth.
-Airway hazard.

Question 9

What is Amphetamine psychosis?

Answer 9

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

Question 10

What kind of drug is Cocaine?

Answer 10

-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.

Question 11

How was cocaine used in medicine?

Answer 11

-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

Question 12

What is the “cycle” of cocaine use?

Answer 12

Use is cyclical:
-Use
-Euphoria
-Depression
-Craving

Dependence and addiction may develop after only a few uses.

Question 13

What effects occur with chronic use of cocaine?

Answer 13

Loss of appetite
Hyperactivity
Insomnia
Increased risk for intracranial hemorrhage, ischemic stroke, MI and seizures
OD = hyperthermia, coma, and death

Question 14

What are withdrawal symptoms of Cocaine?

Answer 14

Similar to but not as strong as that of opioids
-Dysphoria, sweating
-Nausea, vomiting, diarrhea
-Muscle aches, fever
-Lacrimation, rhinorrhea, mydriasis
-Piloerection
-Yawning

Question 15

How is cocaine metabolized?

Answer 15

-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.

Question 16

What are the limits associated with a Urine Drug Screen?

Answer 16

-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)

Question 17

How long will cocaine metabolites appear in a UDS?

Answer 17

-6 days after a single dose
-10-20 days after high dose, long term use

Question 18

What is the MOA of Cocaine?

Answer 18

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

Question 19

What are the results of the increased NE associated with cocaine?

Answer 19

-acute ↑ in arterial pressure, tachycardia, and ventricular arrhythmias.
-Increases in NE agonize SNS. HTN, tachycardia, arrhythmias. Problem for anesthesia.

Question 20

What are the differences between methamphetamine and cocaine?

Answer 20

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.

Question 21

What is a “Speedball”?

Answer 21

-IV cocaine mixed with heroin
-Stimulant + Depressant

Counter the side effects of both drugs
-Pharmaceutical Opioids
-Benzodiazepines
-Barbiturates

Question 22

What kind of drug is Methylene-dioxymethamphetamine (MDMA)?

Answer 22

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

Question 23

What is Serotonin Syndrome?

Answer 23

Too much serotonin.
-Mental status change
-Autonomic hyperactivity
-Neuromuscular abnormalities
-Seizures

Question 24

Why can MDMA lead to water intoxication?

Answer 24

Effects of MDMA are hyperthermia & dehydration. Users hydrate during use. Can lead to water intoxication:
-Severe hyponatremia
-Seizure
-Death

Question 25

What are the withdrawal symptoms of MDMA?

Answer 25

-“Offset” mood – depression lasting possibly several weeks
-Aggression during periods of abstinence in chronic users

Question 26

Substance Abuse/Substance Use Disorders (SUD) are associated with what negative healthcare characteristics?

Answer 26

-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

Question 27

What are indicators/clues to substance abuse?

Answer 27

-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

Question 28

How should you discuss drug use with patients?

Answer 28

-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