Analgesia & Pharmacology Flashcards
What is the most dangerous adverse side effect of opioid analgesics?
Respiratory depression
What are the contraindications to opioids?
Respiratory dysfunction of any cause (including obesity), head trauma, hypotension, shock, hypothyroidism, impaired hepatic function.
What is an endogenous agonist of the mu opioid receptor subtype?
Beta endorphin
All opioid receptor subtypes are linked to which G protein?
Gi/o
What kind of pain do opioids not affect?
Neurogenic pain
What opioid drug class does morphine belong to?
Opioid phenanthrene mu agonist
What opioid drug class does fentanyl belong to?
Meperidine mu agonist
What opioid drug class does loperimide belong to?
Meperidine mu agonist
What opioid drug class does tramadol belong to?
Opioid phenanthrene mu agonist
What opioid drug class does propoxyphene belong to?
Methadone mu agonist
What opioid drug class does buprenorphine belong to?
Mixed agonst/antagonist
What opioid drug class does codeine belong to?
Opioid phenanthrene mu agonist
What opioid drug class does naloxone (Narcan) belong to?
Mu antagonist
What opioid drug class does hydrocodone belong to?
Opioid phenanthrene mu agonist
What drug is used to treat opioid withdrawal?
Clonidine (alpha2 agonist)
Is opioid withdrawal life-threatening?
No!
What are the three structural pieces of all local anesthetics?
Lipophilic aromatic portion, intermediate alkyl chain, and hydrophilic amine portion
Are all local anesthetics that contain a single “i” in the name esters or amides?
Esters
Are all local anesthetics that contain two “i”s in the name esters or amides?
Amides
What is the formula to determine what percentage of local anesthetic is in its neutral or cationic form, given the pH and pKa?
(neutral form)/(cationic form) = 10^(pH-pKa)
When an area is infected, why does a patient need a higher does of local anesthetic?
The pH is lower at the infection site, leading to less available drug in neutral form to cross membranes.
Does a local anesthetic bind the Na channel extracellularly or intracellularly?
Intracellularly
Does the Na channel have higher affinity for local anesthetic in its neutral or charged form?
Charged
Which fiber type is preferentially blocked by local anesthetics?
C fibers
What is the relationship between the pKa of a local anesthetic and its lipid solubility?
The lower the pKa value, the higher the lipid solubility
What is the main mechanism of ester local anesthetic termination?
Hydrolization primarily in plasma by an esterase
What is the main mechanism of amide local anesthetic termination?
Metabolized in liver only
How are local anesthetics excreted?
Renally
Why are many local anesthetics combined with a vasoconstrictor like epinephrine?
The duration will be prolonged dramatically by reducing blood flow thereby retarding systemic absorption.
Where do tetrodotoxin and saxitoxin act on the Na channel?
Extracellular entrance (pore)
How do tetrodotoxin and saxitoxin cause death?
By paralyzing respiratory muscles
What is first line therapy for termination of moderation to severe migraine?
Triptans
What is the mechanism of action of triptans?
5HT 1B/1D receptor agonist
What are some adverse effects of triptans?
Parasthesis, flushing, dizziness, drowsiness, fatigue, pressure in chest, coronary vasospasm & angina, MI, arrhythmia, stroke, death
What is the mechanism of action of ergot alkaloids?
5HT 1B/1D receptor agonist
What is first-line therapy for prevention of chronic migraines?
Propanolol
What two dietary supplements are safe and can possibly prevent migraines?
Riboflavin and butterbur
