9. Pharm: Opioids Flashcards
What are the most common drugs involved in prescription opioid OD deaths?
- Methadone
- Oxycodone
- Hydrocodone
Who is more likely to OD on opioids?
- 25 - 54 YO
- M
- Whites & American-Indian or Alaskan Natives
Opioid AGO (9)
- Morphine
- Hydromorphine
- Methadone
- Oxycodone
- Hydrocodone
- Fentanyl
- Codeine
- Propoxyphene
- Meperidine
Opioid Partial AGO (Mixed AGO/ANT)
- Buprenorphine
- Nalbuphine
- Butorphanol
- Pentazocine
Opioid ANT
- Naloxone
- Naltrexone
General MOA of opioid analgesics
- Binds to opioid receptor in the CNS: close presynaptic Ca2+ channels; open post-synpatic K+ channel => ↓ synaptic transmission => inhibit release of ACh, NE, 5HT, glutamate and substance P
- Inhibiting ascending pain pathways
- Decrease response and pain perception (nociception)
- CNS depression
What is the general onset of action of opioid drugs?
- Depends on the patient: dosing must be individualized
- Oral (immediate release) => work in 30 minutes
- IV => work in 5 - 10 minutes
What is the general duration of pain relief of
- 1. Immediate release opioids (tablet, oral solution or injection)
- 2. Extended release capsule and tablet
- 3. Epidural or intrathecal
- Suppository
- 3- 5 hours
- 8 - 24 hours
- 1 dose lasts up to 24 hours
- 3 -7 hours
Black Box Warning for Opioids
- Can cause respiratory depression: watch closely, especially when initiating or increasing dose.
- CO2 retention from opioid-induced respiratory depression can worsen sedating effects of opiods.
Opioid AE
- CNS depression
- Constipation: problematic in ppl with [unstable angine or post-MI], so consider preventative measures to decrease possib of constiptation (stool softner or fiber)
-
HypOtension: can cause severe hypOtension (including orthostatic hypotension and syncope); use with caution in ppl with
- hypovolemia/shock
- CV disease
- Drugs that worsen hypotensive effects (phenothiasinzes or general anesthetics)
What opioid is the most potent?
fentanyl > buprenorphine
Indications for Opioids
Manage pain and acute/chronic pain in patients with
- MI
- Sickle cell crisis
- Post-op
- Trauma/cancer
- Back pain
- Kidney stones
- General anesthesia/epidural anesthesia
- Palliative care
- Antitussive
- Anti-diarrheal (Loperamide)
Types of opioid receptors
1. Mu (u)
2. Delta
3. Kappa
Mu receptors respond best to what endogenous opioid peptides?
endorphins > enkaphalins > dysnorphins
Delta receptors respond best to what endogenous opioid peptides?
Enkephalins > [endorphins and dysnorphins]