Opioids (Exam #1) Flashcards
What is the general MOA of all opioid receptors (3)? What additional mechanism is seen with mu receptors?
- Decrease cAMP via Gi proteins
- Close presynaptic Ca channels
- Decrease NT release
Mu also OPEN K channels = hyper polarization
What are the four major effects of opioids, and with which might you develop tolerance?
- Analgesia = develop tolerance
- Sedation/mental clouding
- Euphoria vs. Dysphoria
Which opioid is most likely to induce N/V?
Morphine (injected)
What two opioids are utilized as cough suppressants, and which can also be used as a very mild analgesic?
- Codeine (MILD analgesic also)
- Dextromethorphan
What AE is more common in overdose, and in what population should opioids be avoided for this reason?
Respiratory depression
- Avoid in asthmatics/pulm disease
With what opioid effect is there NO tolerance, and what drug is the exception to this? What other two effects have NO tolerance (no exceptions with these)?
Miosis (pupil constriction) = can always tell on PE
- Meperidine because also an anticholinergic
Also, constipation and seizures
What GI AE is most common with opioids? What GU AE is most common with opioids?
- GI: Constipation
- GU: urinary retention
What two findings are commonly seen with injected Morphine?
- N/V
- Histamine release (flushing, itching, sweating)
What two opioids should NOT be combined with MAOIs?
- Meperidine
- Dextromethorphan
Which two opioids should NOT be combined with CYP2D6 inhibitors, and what is an example of an inhibitor? What opioid could be used as an alternative in this scenario?
Fluoxetine = CYP2D6 inhibitor
- Codeine
- Oxycodone
Can use Oxymorphone with Fluoxetine
What is the major CI associated with opioids, and why is this?
Use of a partial agonist with a full agonist
- Can induce withdrawal
What is the prototype opioid drug, and what receptors does it stimulate - how does this affect its effects?
Morphine
- Stimulates ALL receptors
- Produces ALL effects of opioids (good for severe pain)
In what population would you use Hydromoprhone (Dilaudid) over Morphine, and why?
Renal dysfunction
- Metabolites don’t accumulate
What is the primary use of Methadone (Dolophine), and why is this?
Long-term pain control
- Long DOA and half-life (most others are short)
What is the MOA of Methadone (Dolophine) (2)?
- Block glutamate receptors
- Inhibit 5-HT reuptake
What are the two major CIs associated with Meperidine, and what AE can result if not followed?
Can cause seizures
- 48+ hours of use
- Renal failure
What two signs/sxs are seen with Meperidine use (different from most opioids)?
- Pupil dilation
- Tachycardia
What opioid has a very high abuse potential due to its high potency?
Fentanyl
What are the two “work horse” opioids, and what are they often combined with? What is their primary use?
Moderate/severe pain
- Hydrocodone
- Oxycodone
Often combined with Acetaminophen
What can be added to Oxycodone to prevent opioid effects if injected?
Naloxone/Naltrexone
What opioid is a kappa receptor agonist and mild mu receptor partial agonist? What effect may be seen?
Pentazocine/Naloxone
- May see dysphoria (due to kappa)
What medication can be used to treat opioid addiction, and how does it do this?
Buprenorphine
- Reduces cravings
What is the MOA of Tramadol?
Weak mu agonist
- Inhibits NE and 5-HT reuptake
What AE may be seen if Tramadol is combined with antidepressants? What AE is seen with MAOIs, TCAs, SSRIs?
- Antidepressants = seizures
- MAOIs/TCAs/SSRIs = Serotonin Syndrome
What is the DOC for opioid overdose?
Naloxone (Narcan)
How does Naloxone (Narcan) differ from Naltrexone?
- Naloxone (Narcan) = short DOA (2 hours)
- Naltrexone = longer DOA (24 hours)
What is the primary use of Naltrexone? What other use can it provide?
Used in tx of opioid addicts (especially in HC)
- Can decrease cravings in recovering alcoholics
What medication will precipitate withdrawal in patient dependent opioids (i.e. can cause withdrawal as drug is eliminated from body)?
Naltrexone
What two opioids are partial agonists? What are they often combined with, and why?
Combined with Naloxone to reduce abuse potential
- Pentazocine/Naloxone
- Buprenorphine
