Narcotics Flashcards
Name the three main properties of opioids.
Analgesia, Antitussive, Constipation
Define opioid.
Generic term for natural and synthetic substances that bind opioid receptors.
Name the three types of opioid receptors.
Delta, Mu, Kappa
What results from opioid receptor agonism?
Reduction is secretion of pain inducing neurotransmitters.
What is the dose limiting adverse effect of narcotics?
Respiratory depression
List additional adverse effects of narcotics other than the dose limiting A/E.
Sedation, reduced peristalsis, pruritis (HST), N/V, miosis, peripheral vasodilation (causing HypoTN)
Why might narcotics cause worsening pain in patients with pancreatic disease?
Narcotics cause contraction of the sphincter of Oddi increasing pressure on the biliary tree.
Which narcotic is the best option for pain in patients with pancreatic disease?
Meperidine
What is the antidote for narcotics and what is the potential adverse effect?
Naloxone - may cause acute withdrawal
How is naloxone distributed to EMTs and lay people in Kentucky?
injection and inhaled forms
What two factors primarily affect the kinetics of different narcotic agents?
half life and volume of distribution
What narcotic binds to plasma esterases and how does this affect its kinetics?
Remifentanil - causes the drug to have a very short half life
T/F: The effects of narcotics are consistent from one person to the next for a given dose.
False - wide variability
List 5 routes of administration for narcotics mentioned in class.
IV, SC, TD (transdermal - patch), IT (intrathecal - in the spine), PCA (patient conroled - pump)
What pharmacokinetic characteristic differentiates morphine from most other opioids?
Morphine is highly water soluble
Why is morphine the preferred narcotic in chest pain?
Reduces sympathetic tone and causes less reflex tachycardia compared to other narcotics.
Differentiate PO morphine from IV morphine and explain why?
PO morphine requires 6 times the IV dose to have the same effect because PO morphine is significantly impacted by first pass effect in the liver.
Describe the potency of meperidine relative to morphine.
Much less potent –> 75-100 mg meperidine = 10mg morphine
Describe the pharmacokinetcs of meperidine relative to the liver and kidneys.
Meperidine is metabolized to normeperidine in the liver. Normeperidine accumulates in renal failure patients resulting in a decreased seizure threshold.
Why does meperidine have more of a role in obstetrics than other narcotics?
Most narcotics decrease uterine contractions and prolong labor. Meperidine does not have this effect.
Why is meperidine avoided in chest pain?
reflex tachycardia
T/F: Meperidine is a weak antitussive and has anticholinergic properties.
True
List and describe the three drugs used to ween addicts off of narcotics.
- Naltrexone: Long acting form of naloxone that reduces euphoria in stable addicts.
- Methadone: Very long acting narcotic with large Vd.
- Bupenorphine: Opioid agonist/antagonist
What is the injectable form of naltrexone?
Vivitrol
What is the common name for diamorphine and what is special about its distribution?
Diamorphine = heroin. It is morphine bound to fat allowing it to easily cross the blood brain barrier.
What is the primary use of codeine?
Pain above the shoulders (dental pain)
What NSAID is codeine combined with to make Codeine #3?
Acetaminophen - APAP
Compare the potency of oxycodone with morphine.
Oxycodone is 2x more potent than morphine.
With what NSAIDs is oxycodone combined and in what distribution forms?
Combined with aspirin and acetaminophen in immediate release and controlled release forms.
Name the drug combinations that form percocet and percodan.
Percocet = Oxycodone + APAP Percodan = Oxycodone + ASA
How is hydrocodone most commonly available?
In several co-formulations
Name two coformulations of hydrocodone and APAP.
Vicodin and Lortab
What are the two narcotics most commonly used to treat outpatient pain?
Oxycodone and hydrocodone
Describe the potency of hydromorphone compared to morphine.
PO is 5 x more potent and IV 8 x more potent.
What is the caution with methadone and why is it a concern?
Prolongs QT interval –> can cause torsades
What is true about the half life of fentanyl?
Very short half life (short acting) but the half life increases at higher doses.
Describe the potency of fentanyl.
Most potent narcotic –> 100x potency of morphine
Why is fentanyl often used as a TD patch and how often should the patch be replaced?
Fentanyl has high lipophilicity and the patch should be replaced every 72 hours.
By what factors do fentanyl analogues differ from each other.
Differ in potency and half life
How is dextromethorphan related to other narcotics and how is it used?
4th cousin to narcotics - used as an antitussive
What is the initial dose of naloxone for opioid OD and what is the dose if given via ET tube?
2mg - double the dose via ETT
Which narcotics require a significantly increased amount of naloxone to reverse an overdose?
Pentazocine, propoxyphene, codeine, methadone
What is true about the half life of naloxone compared to opioids and how is this managed?
Opioids have a longer half life than naloxone. After initial naloxone bolus, infuse at an hourly rate that is 2/3 the amount required to reverse the OD.
In addition to opioid use, what other substance is PO naltrexone used for?
Alcohol dependence
How often is vivitrol redosed.
Injected q month
What drug, related to naltrexone, is used for opioid induced constipation?
Methylnaltrexone
