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