Opioids (Wolff) Flashcards
What are the three major classes of opioid receptors?
mu, kappa and delta
Morphine and other pure opioid agonists relieve pain by mimicking the action of?
Primarily at what receptors?
1) Endogenous opioid peptides (endorphins, enkephalins, etc.)
2) Mu receptors but partly at kappa receptors
What is the most serious adverse effect of opioids?
Respiratory depression
What precautions are there for opioid use?
1) Pregnancy
2) Head injury
Opioid overdose produces what classic triad of signs?
1) Coma
2) Respiratory depression
3) Pinpoint pupils
Which pure opioid is 100X more potent than morphine, has the same adverse effects, and is notable for having multiple formulations?
fentanyl
alfentanil, remifentanil, and sufentanil are pure opioids used for?
Which is an IV opioid with rapid onset and brief duration due to rapid metabolism by blood esterase?
1) Induction and maintenance of anesthesia
2) remifentanil
Meperidine (Demerol) which is often abused by healthcare workers because of its anticholinergic effects lacks what classic sign of other opioids?
Lacks pinpoint pupils
Methadone which shares major properties of morphine, is also an antagonist of what other receptor?
NMDA receptor
Which pure opioid is indicated for moderate to severe pain, adverse effects are similar to morphine and reversed by naloxone, and is more water soluble so can be diluted in a smaller volume for injection?
hydromorphone (Dilaudid)
What is the prototype for moderate to strong opioid agonists?
Codeine
~10% of each dose of codeine is metabolized to morphine by what CYP?
CYP2D6
Oxycodone which is a moderate to strong opioid agonist similar to codeine, is metabolized by which CYP?
CYP3A4
What type of opioid is pentazocine and butorphanol?
Mu antagonist and Kappa agonist
What type of opioid is buprenorphine?
Mu partial agonist and Kappa antagonist
Naloxone and naltrexone are what type of drugs?
Pure Opioid Antagonists
What effect does Naloxone have?
Reverses most effects of opioid agonists including respiratory depression
What does naloxone precipitate in people who are psychically dependent on opioids?
Immediate withdrawal reaction
What effects do naltrexone have?
1) Prevents euphoria from opioids but does not prevent craving
2) Reduces craving and heavy drinking associated with alcoholics
What is methylnaltrexone?
What is it indicated for?
1) μ-opioid antagonist that cannot readily cross BBB
2) Opioid-induced constipation
What is loperamide?
What is it indicated for?
1) μ-opioid agonist that cannot readily cross BBB
2) Acute and chronic diarrhea
Patients that ingest loperamide in large quantities to get high or alleviate withdrawal symptoms have a great risk of?
Torsade’s de pointes due to QT prolongation
How is it best to administer opioids?
On a fixed schedule
In the setting of renal insufficiency which opioid is safe for use?
Which are not recommended because of toxicity of their metabolites?
1) Fentanyl
2) Meperidine and codeine
In the setting of hepatic insufficiency which opioid is safe for use?
Which are not recommended because of toxicity of their metabolites?
1 Fentanyl
2) Meperidine, codeine, and methadone
What is the outcome of adverse interactions between opioids and CNS depressants such as:
Barbiturates Benzodiazepines Alcohol General anesthetics Antihistamines Phenothiazines
Increased respiratory depression and sedation
What is the outcome of adverse interactions between opioids and Agonist-antagonist opioids?
Precipitation of withdrawal reaction
What is the outcome of adverse interactions between opioids and Anticholinergic Drugs such as:
Atropine-like drugs
Antihistamines
Phenothiazines
Tricyclic antidepressants
Increased constipation and urinary retention
What is the outcome of adverse interactions between opioids and hypotensive agents?
Increased hypotension
What is the outcome of adverse interactions between opioids and Monoamine oxidase inhibitors?
Hyperpyrexic coma
