37_Drugs of Abuse Flashcards
What is tolerance?
Used to a certain dose of a drug so have to increase the dose just to get the same effect.
This is an adaptive change to a drug
What is dependence?
When the drug dose decreases or starts wearing off, you get WITHDRAWAL symptoms
Adaptive change becomes maladaptive.
Formerly called physical dependence
What is addiction?
Compulsive relapsing drug use despite negative consequences
Formerly called psychological dependence
What pathway do addictive drugs use? What is it about this pathway that causes the drug to become addictive?
If a drug uses the mesolimbic dopamine system then it will become addictive
This pathway involves dopamine which is involved the rewarding of constructive behaviors
-drugs that increase dopaminergic tone in these pthwys INAPPROPRIATELY reinforce behaviors which can become compulsive
Not all drugs that use the dopamine pathway are addictive. What are these drugs?
Antipsychotics
Antidepressants
Anti-Parkinsonian
What is an opiate and what drugs are derived from it?
It is a naturally occurring analgesic alkaloid found in opium
Drugs
- Morphine, Codeine, many others
What is an opioid?
These are agents that produce opiate like effects &/o bind to opiate receptors
Natural Opioid: Its an Endorphin
Semi-Synthetic: Chemical modification of opiate (Oxycodone, Heroin)
Synthetic: Structurally different from morphine but has similar effects (Fentanyl, Methadone, Meperidine)
What are the Semi Synthetic Opioids?
Oxycodone, Heroin
What are the synthetic Opioids?
Fentanyl, Methadone, Meperidine
What is heroin AKA? what is the difference btwn heroin and morphine?
It is AKA diacetylmorphine
Two of the hydroxyl groups acetylated (morphine just has the two hydroxyl groups which make it more polar). The acetylation makes it more lipid soluble so it can cross the BBB. This causes stronger euphoriant effects
De-acetylation can occur spontanously
How do you use heroin?
The faster its gets into your brain, the better the euphoriant effects
PO: delay in absorption (opium eating)
Inhalation: Large respiratory surface area
Parenteral Injection: IV so 100% bioavailability
Describe IV Heroin use injection sites.
Most common are the injections into the Antecubital and forearm veins. They are superficial and easily accessible.
Track Marks
If these aren’t available or want to avoid them then use
Dorsum of foot btwn toes
Breast Veins
Penile Dorsal Vein
What are the alternate venous access sites for heroin use?
Dorsum of Foot btwn toes
Breast Veins
Penile Dorsal Veins
Describe Jugular vein access in heroin abuse
ie Pocket Shot & Shooting Gallery
Pocket shot is where there is an IV injection lateral to SCM and above clavicle to hit INTERNAL JUGULAR. Hold nose and do Valsalva maneuver so the IJ & EJ veins are dilated
Shooting Gallery is a place where you pay someone to give you a pocket shot
What is the risk for doing Pocket Shots
Pneumothorax Hematoma Aneurysm Infection AV fistula
What is skin popping? who is this seen in? what are the risks of this?
When venous access not an option, so the drug is injected under the skin.
common in long term users, and get recurrent skin & soft tissue infections that leave cratered scars
What are the risks of parenteral Heroin Injection?
Overdose
Primary Infection
- Bloodborne, ie HIV, Hep B/C, Malaria
- Bacterial ie Endocarditis, Phlebitis (DVT, Aneurysm, Fistula), Local Skin & Soft Tissue Necrosis
Secondary Infection
- esp in Skin Poppers ie wound botulism, tetanus
Non Drug Effects
- Pulmonary Talc microemboli
- Cotton Fever
- Contamination (Quinine, Strychnine, Atropine, Thallium, etc)
How is heroin inhaled?
What is chasing the dragon associated with?
Placed on foil heated with lighter or matches that liquefies into a glob (dragon)
Dragon moves around emitting vapors which move around and you chase and inhale through a straw
Chasing the dragon is associated with Leukoencephalopathy
Other Opioid Abuses
Meperidine…why is it not used as much anymore? What is the metabolite and what does it cause?
Not used as much bc drug seeking patients kept asking for it by name. Now they ask for dilaudid (hydromorphine)
Metabolite is normeperidine and is NEUROTOXIC
-causes agitation and seizures
Other Opioid Abuses
MPTP…What is it, and what drug what is it modeled after? What is it metabolized into and what effects does this metabolite have on the body?
It is a synthetic designer drug modeled on MEPERIDINE
Metabolized into MPP+ which KILLS DOPAMINERGIC CELLS IN THE SUBSTANTIA NIGRA…leads to Parkinsons Disease
These are called frozen addicts
What is the toxidrome of Opiate Overdose?
What does overdose mimic, i guess meaning, what other things could it look like?
Toxidrome:
CNS depression
Respiratory Depression
Miosis
Potential Mimics:
Hypoglycemia, Hypoxia, Hypothermia
Imidazoline Drugs: central a2 agonists
CNS Injury / Pontine Hemorrhage
How do you treat opiate overdose?
What is death most likely due to?
ABCs / supportive care
Antidote = Naloxone
- Narcan which is a NARCotic ANtagonist
- IV, IM, IN, nebulized, per ETT
Its short acting tho, need to observe for re-sedation
May bring about acute w/drawal so use smallest dose necessary
Overdose death most likely due to decreased ventilation
What are signs & symptoms of opioid w/drawal?
Signs: Pupillary Dilation Sweating Piloerection (goosebumps) Tachy N/V Diarrhea HTN Yawning
Symptoms Cravings for Opioids Restlessness, Irritability Increased Sensitivity to pain Nausea, cramps Myalgia Insomnia, Anxiety
Is Opioid Withdrawal life threatening?
Nope. Its just unpleasant
How is opioid withdrawal treated?
Cross Tolerance - switch to a Rx opioid and gradually decrease the dose
Clonidine: this is an a2 agonist used for HTN; reduces autonomic symptoms of withdrawal
Activate endogenous opioids
How can Methadone deter opioid abuse?
Use Methadone
Substitute long acting once daily methadone for multiple doses of illicit and more dangerous drug
Have to monitor this so this is limited to accredited outpatient programs
Patients can be weaned off methadone but many continue indefinitely
