Opioid Pharmacology Flashcards
What type of opioid agonist is morphine
codeine
hydrocodone
meperidine?
Pure opioid agonist at the mu and Kappa receptor
What is pentazocine MOA?
antagonist at mu
agonist at kappa
What is butorphanol MOA?
partial agonist at mu
agonist at kappa
What is buprenorphine MOA?
partial agonist at mu
antagonist at kappa
What is mechanism of naloxone and naltrexone?
Antagonist at mu
antagonist at kappa
Are oral or parenteral doses of morphine larger?
morphine undergoes significant first-pass metabolism (conjugation), so oral doses are larger than parenteral doses
What is the triad of opioid overdose?
- coma
- respiratory depression
- pinpoint pupils
How is fentanyl metabolized?
100X more potent, same adverse effects… CYP3A4 substrate, t1/2 2-4 hrs
What is notable about fentanyl?
notable for multiple formulations including IM IV transdermal transmucosal nasal spray lozenge on stick buccal tablets
What drugs are used for induction of anesthesia, maintenance of anesthesia in combination with other agents, and as sole anesthetic agents?
- Alfentanil
- Remifentanil
- Sufentanil
What drug is an IV opioid with rapid onset and brief duration due to rapid metabolism by blood esterases… effects begin in minutes and end 5-10 min after infusion is stopped, also used for immediate postoperative analgesia?
Remifentanil
What drug is often abused by healthcare workers because it has anticholinergic effects, so lacks pinpoint pupils of other opioids, also contributing to eradication efforts
Meperidine (demerol)
What is methadone MOA?
Shares properties with morphine, is an NMDA receptor antagonist with a long duration of action
What has a higher lipid solubility than morphine and gives a greater high?
Heroin
What is indicated for sever/moderate pain, is reversed by naloxone, and is more water soluble so can be diluted in a smaller volume for injections?
Hydromorphone (dilaudid)
-oxymorphone, levorphanol
~10% of codeine is metabolized to morphine by what enzyme? What happens if this enzyme is absent?
10% of each dose of codeine is metabolized to morphine by CYP2D6 … required for analgesia
• some lack this gene so codeine is ineffective
What opioid agonist is extremely effective as a cough suppressant?
Codeine
What enzyme metabolizes oxycodone? Why is this significant?
CYP3A4 metabolizes oxycodone–> inducers (e.g., carbamazepine, phenytoin) can lower levels and inhibitors (e.g., “azole” antifungal drugs) can raise levels
What is pentazocine MOA?
- agonist-antagonist opioid prototype
- Agonist of kappa opiate receptors and antagonist of mu opiate receptors in the CNS–> inhibits ascending pathway
What is MOA of oxycodone
moderate to strong opioid agonist, similar to codeine
What is MOA of hydrocodone?
moderate to strong opioid agonist, similar to codeine
- available only in combination with other drugs (acetaminophen, aspirin, ibuprofen
What is MOA of butorphanol?
- agonist-antagonist opioid usted to treat mild to moderate pain
- kappa opioid receptor agonist
- mu opioid receptor partial agonist
What drug differs significantly from other agonist-antagonists in that it is a kappa opioid receptor antagonist and partial agonist at mu opioid receptors?
Buprenorphine - used primarily to treat addicts
- prolongs QT interval, so risk of fatal dysrhythmias
• can cause spasm of sphincter of Oddi, poses risk for patients with pancreatitis or biliary disease
What type of drug is naloxone? what is it used for?
Narcan in a pure opioid antagonist used for reversal of effects of most opioid agonists
