Lecture 42: Opioid Cornish lecture Flashcards
What is the nation’s number one health problem?
Substance Abuse
- most people don’t feel like they need treatment
- no health coverage
What is epidemiology of opioid dependence?
2.2 million use pain relievers NONMEDICALLY
Only 200,000 receiving treatment
-second most widely used drug after marijuana
What are opioids?
Any chemical compound with pharmacologic actions similar to those of morphine
-narcotic analgesic is often referred to opioids
What are the actions of opioids?
CNS: analgesia, euphoria, sedation, respiratory depression Anti-tussive effects Peripheral Vasodilation Pupil CONSTRCITION Respiratory depression PARASYMPATHETIC
What is Demerol?
An opiate pain reliever
Like Oxycontin and vicodin
What is the MOA of opioids?
They act on the (mu), (kappa) and (delta) opioid receptors…all of which are coupled to Gi GPCRs
Opioids bind to GABA neurons which INHIBITS GABA and thus stimulates dopamine
Ultimate effect = increase dopamine in synapse
What is the significance of kappa opioid receptors?
Expressed on dopamine neurons
Binding INHIBITS dopamine
-causes DYSPHORIC effects
What are the most commonly abused (mu) opiods?
Morphine
Heroin (diacetylmorphine, rapidly metabolized to morphine)
Codeine
Oxycodone
What is an opioid that is commonly abused by physicians?
Meperidine
What is abuse?
Culturally disapproved use
What is dependence?
Tolerance
Neuroadaptation
Repeat doses or withdrawal
How addictive are opioids?
Highly addictive (on a scale of 1-5…it is a 4 so closer to highly addictive) Addictive only when used recreationally, not when they are taken as analgesics
How do you treat people with opioid addiction?
Nalaxone (acute reversal of symptoms with acute withdrawal)
Methadone and buprenorphine (long-acting opioids that are less rewarding)
-longer halflife/partial opioid agonists
-used to taper off…methadone given onece a day
-abrupt termination leads to withdrawal/dependence
What is the significance of Methadone?
A long-acting opioid that is used to treat opioid addiction
-used to help taper people off from drugs like heroin
What is Nalaxone?
An antagonist of opioids that reverses the effect of morphine and heroin within minutes
What are the drugs that increase dopamine in nucleus accumbens?
- Nicotine
- Alcohol
- Opioids
- Cocaine
What is a speed ball?
Cocaine + heroine
Opioid drugs are classified as:
- full agonists
Example: morphine: full agonist of mu receptor - partial agonists
Example: codeine: partial agonist of mu receptor - antagonists
Example: Naloxone: full antagonist of mu receptor
What are endogenous opioid peptides?
Peptides made in the body that bind to opioid receptors
Example: ENDORPHINS, enkephalins, dynorphines, leu-enkphalin
hat is the difference between naloxone and naltrexone?
Both are opioid receptor antagonists Naltrexone is LONGER acting (because it has longer name), so used for chronic treatment -given PO -used for ALCOHOL dependence Naloxone used for acute -given IV -used for OPIOID dependence
What are the withdrawal symptoms of Opioids?
- Anxiety
- Sweating
- pupillary DILATION (because opioids constrict pupils)
- Rhinitis
- Diarrhea
- Incraesed BP and respiratory rate
- Craving
What are the benefits of methadone?
-oral, long-acting and cheap
-blocking dose
-eliminates injection risks
-constant maintenance of methadone level vs. heroine which goes up an down
Methadon is like Irms while Heroine is like Imax and Imin
What is Buprenorphine?
A partial mu-opioid agonist -ceiling effect at higher doses -does not stop withdrawal symptoms -lower level of dependence HIGH affinity and SLOW dissociation
What is Naltrexone used for?
Relapse prevention for BOTH opioid AND alcohol
Specific antagonist of mu-receptor
-very few adverse effects
PO and non-addicting