Pharm: Opioids Flashcards
Which opioids are U+K agonists?
(hint: it’s most of them)
morphine
fentanyl
alfentanil/sufentanil
remifentanil
meperidine
codeine
hydrocodone
oxycodone
methadone
hydromorphine
Which opioids are U antagonists and K agonists?
pentazocine
butorphanol
Which opioids are U ptAg and K antagonists?
buprenorphine
Which drugs are opioid antagonists?
Naloxone
Naltrexone
Which opioids are “non-absorbed”?
Loperamine
Methylnaltrexone
What is the most serious adverse effect of opioids?
respiratory depression
Why are oral doses of morphine higher than parental doses?
due to significant first-pass metabolism
Why are smaller doses of opioids necessary in infants?
due to poorly developed BBB
With prolonged use, tolerance develops to which effects of opioids?
Tolerance does not develop to which symptoms?
tolerance develops to analgesia, euphoria, sedation and respiratory depression
Tolerance does not develop to constipation and miosis
Is opioid withdrawal deadly?
No, but abstinence syndrome is unpleasant and can be avoiding by gradually withdrawing the medication
Opioids should be used with caution or avoided in whom?
pregnant patients
avoided with alcohol
avoided with anticholinergics
What is the classic triad of opioid overdose?
coma
respiratory depression
pinpoint pupils
Which drug is 100x more potent with the same adverse effect profile as morphine?
Fentanyl
*has multiple formulations-IM, IV, patch, spray, lozenge, etc.
Which drugs can be used as induction of anesthesia, maintenance of or sole agents for anesthesia?
Of these, which is the IV opioid with the most rapid onset and briefest duration?
Alfentanil, Remifentanil, Sufentanil
Remifentanil
What drug was considered first line therapy for migraines and other pain conditions but is now in decline?
Meperidine (Demerol)
Why is Demerol use (Meperidine) in decline?
it has a short half life and needs frequent dosing
has several adverse interactions with other drugs
often abused by healthcare professionals due to anticholinergic effects (no pinpoint pupils, etc)
Which opioid also acts as an NMDA receptor antagonist?
What are some reasons that this drug causes disproportionate numbers of deaths?
Methadone
can cause QT prolongation and Torsades especially when combined with other drugs that prolong QTI
Why does heroin give a better “high” than morphine?
due to it’s higher lipid solubility
schedule I substance in US, but available therapeutically elsewhere
What is the indication for hydromorphone (Dilauded)?
How can it be reversed?
Is it more lipid or water soluble?
indicated for moderate to severe pain with similar adverse effects to morphine
Reverse with naloxone
More water soluble, so can be diluted in smaller volume for injection
What drug is the prototype for moderate to strong opioid agonists?
How is it metabolized?
Codeine
10% of each dose is metabolized to morphine by
CYP2D6–>required for analgesia
What are two special features of Codeine?
It can be formulated with nonopioid analgesics or used alone
It is an effective cough suppressant
What is special about oxycodone’s metabolism?
It is metabolized by CYP3A4 so inducers like carbamazepine or phenytoin can lower levels, and inhibitors like “azoles” can raise levels
What is Naloxone (Narcan) and what is it used for?
pure opioid antagonist
can reverse most effects of opioid agonists
*if given in the absence of opioids, it has no significant effect
What happens if Naloxone is given to a patient with a physical dependence on opioids?
It will precipitate immediate withdrawal reactions
What is Naltrexone and what is it used for?
pure opioid antagonist
prevents euphoria, not cravings
can be used in alcoholics (can reduce craving and drinking in this case) while Acamprosate can decrease ETOH consumption to a greater degree with lesser effect on cravings
What is methylnaltrexone?
u-opioid antagonist that cannot readily cross the BBB
indicated for opioid-induced constipation in patients with end-stage disease
What is loperamide?
u-opioid agonist that cannot readily cross the BBB
indicated for acute and chronic diarrhea
in large doses, can cause Torsades (QT prolongation)
What are three keys to remember about the clinical use of opioids?
Pain is subjective and cannot be measured
No such thing as a “Standard Dose” of opioids
Best to administer with a fixed schedule and tx breakthrough pain as necessary
For mild-severe pain, after topical agents, and OTC analgesics have proved ineffective and TCAs are not alleviating the pain, what is the next best option?
Opioids +/- Baclofen if spasmodic component
What is the safest option for patients with renal and hepatic insufficiency?
Fentanyl
(methadone is safe in renal insuf., but can only be used by docs with prior experience)
Why is fentanyl safe for patients with hepatic insuffiecient?
metabolized by CYP3A4 but pharmokinecally has no significant effect from cirrhosis due to normally high rate of elimination in a single pass through the liver
What technique can be employed to have a favorable balance between pain relief and adverse effects when treating with opioids?
Can place pt on opioid rotation
