E1: Opiods Flashcards
What are the endogenous opioid peptides?
Enkephalines, beta-endorphin, and dynorphin
How do beta-endorphins work?
Decreased pain transmission in the spinal cord and facilitate dopamine in reward system, causing euphoria
How do enkephalins work?
Decrease pain transmission in the spinal cord
How do dynorphins work?
Binds to Kappa receptors, may produce analgesia
What are the main effects of opioids?
Analgesia, sedation, euphoria, dysphoria
What receptors are involved in dysphoria?
Kappa and delta
What opioids are used for cough? Which does NOT suppress cough?
- Codeine and dextromethorphan (no analgesia) used for cough
- Meriperidine doesn’t suppress cough
What are the adverse effects of opioids?
- Nausea and vomiting
- Constipation
- Urinary retention
- itching
- respiratory depression
- postural hypotension
- restlessness
- dysphoria
Although tolerance developed to opioids, what effects of opioids do patients NOT become tolerant to?
Mitosis, constipation, and seizures
What can you use to reduce the symptoms of opiate withdrawal?
Clonidine or another opioid such as methadone
What is the treatment for opioid overdose?
- Support respiration
- Narcan
What are the contraindications to opioids?
- Use of a partial agonist with a full agonist
- Head injuries
- Pregnancy
- impaired pulmonary function
- impaired hepatic or renal function
- some endocrine diseases
What is the MOA of morphine?
Strong agonist that stimulates all opioid receptors
How is Morphine metabolized?
- In the liver by CYP2D6
- high first pass metabolism when injected
What are the side effects of morphine?
May cause itching or vomiting when injected due to histamine release
What is morphine metabolized to?
It is conjugated or glucuronide compounds
- Morphine-6- glucuronide is potent analgesic
- Morphine-3-glucuronide may cause adverse effects if it accumulates
What is the MOA of Methadone?
- Stimualtes mu receptors
- ma also block NMDA receptors and inhibit NE/Serotonin reuptake
What is the use of methadone?
- Traditionally used for maintenance treatment of addicts
- now commonly used in long term control of pain
How long should Meperidine be used and why?
- Should NOT be used for more than 48 hours in high doses or in renal failure due to accumulation of the metabolite normeperidine
- Normeperidine can cause seizures
What kind of drug should NOT be given with Meriperidine?
MAOIs- may cause serotonin syndrome
What is the duration of action of methadone?
What about morphine/dilaudid?
Methadone: long
Morphine/dilaudid: 4-6 hours, fairly short half life
What is the duration of action of Fentanyl?
-Short, which is why it has a high abuse potential
What may fentanyl cause when given IV?
Truncal rigidity
How is Fentanyl metabolized?
CYP3A4
What is hydrocodone often combined with?
Tylenol
Why doesn’t hydrocodone work well for patients taking SSRIs?
Hydrocodone requires conversion by CYP2D6 for some of the analgesic effect, and some SSRIs are CYP inducers
Which opioids are metabolized to their active form by CYP2D6?
Codeine, oxycodone, and hydrocodone
What is the MOA of Pentazocine/Naloxone?
- Kappa receptor agonist
- Mu receptor partial agonist
What are the potential side effects of Pentazocine/Naloxone?
- Less sedating than other opioids
- less respiratory depression and GI effects of other opioids
- may cause dysphoria
What is the MOA of Buprenorphine?
-Partial agonist of mu and maybe kappa
What is the use of Buprenorphine?
- Used for maintenance treatment of opioid addiction, decreases craving
- combined with Naloxone
What is the MOA of Tramadol?
- weak mu agonist
- inhibits NE/serotonin ic reuptake
What drugs cannot be combined with tramadol and why?
- Antidepressants: seizures
- MAOIs, TCAs, SSRIs: may cause serotonin syndrome
What is the MOA of Dextromethorphan?
- Blocks NMDA receptors
- Decreases serotoninc reuptake: serotoninc syndrome with MAOIs
What is Dextromethorphan used for?
- Often combined with guafenisen for cough suppressant
- not an analgesic
What drugs may precipitate withdrawal in opioid dependent individuals?
Opioid antagonists
What is the DOC of opioid overdose?
Naloxone
What is the used of Naltrexone?
- used in treatment of opioid addicts, especially health care professionals
- long acting preparation injected to treat addiction, but results may be better with Buprenorphine/Naloxone
- will precipitate withdrawal in patients dependent on opioids
