Opioids Flashcards
High efficacy agonist- prototype against which all others are compared
Morphine
High efficacy agonist- much less potent than morphine but faster acting.
Meperidine (demerol)
High efficacy agonist- Used to treat Heroin addicts. Has a long T1/2 and good bioavailability.
Methadone (Dolophine)
High efficacy agonist- prodrug that is rapidly converted to morphine. Metabolites are the active agents. Not legal in US (schedule 1 drug)
Heroin
High efficacy agonist- more lipophilic than morphine and 75-100X more potent. Short acting and can be given via many routes (lollipop, transdermal patch, orally, buccally, sublingual and nasal spray.
Fentanyl
Medium efficacy agonist- good anti-tussive
Codeine
Medium efficacy agonist- highest efficacy in this category.
Oxycodone (Percocet, percodan, Combunox) OxyContin (slow release preparation)
Mixed agonist/antagonist/other- Only give this orally due to severe injection site necrosis and sepsis when given IV.
Pentazocine (schedule IV)
Mixed agonist/antagonist/other- risk of seizures, avoid taking with MAOI’s (serotonin syndrome)
Tramadol (Ultram, UltramER)
Mixed agonist/antagonist/other- analgesic effects due to mu partial agonism, also kappa antagonist. SL route preferred. Widely used to treat opioid dependence.
Buprenorphine
Antagonist- competitive antagonist at ALL opioid receptors (but not at non-opioid receptors like DM). IV only. Use for treatment of opioid overdose. Short duration of 1 hr.
Naloxone (Narcan)
Non-analgesic opioids- Anti-tussive that is not active at opioid receptors but is at DM receptors.
Dextromethorphan
Non-analgesic opioids- Anti-diarrheal, little BBB penetration. Active ingredient in Imodium-AD
Loperamide
Derived from opium
Opiate
Compound with similar pharmacology to morphine
Opioid
Pain relieving
Analgesic
Sleep inducing
Narcotic
Endogenous opioid ligand released from pituitary as a hormone and also present as a neurotransmitter
Beta endorphins
Endogenous opioid ligand- only in brain and spinal cord.
Enkephalins
Endogenous opioid ligand- only in brain and spinal cord.
Dynorphins
The major receptor for most opioid drugs
Mu
Theraputic effect of opioid- Systemic
Analgesia and anesthesia (but not for neuropathic pain)
Theraputic effect of opioid- Respiratory
Anti-tussive (but may allow accumulation of secretions and airway compromise). Not mediated by opioid receptors, mediated by DM receptors.
Theraputic effect of opioid- GI
Antidiarrheal (but causes constipation)
Theraputic effect of opioid- cardiac
Relief of acute pulmonary edema, reduces preload, afterload and anxiety (but can cause respiratory depression)
Theraputic effect of opioid- psyche
Mood enhancement- contributes to relief of pain and suffering (but leads to abuse liability)
AE’s of Opioids
Constipation Nausea, vomiting (can give with Zofran (ondansetron) to alleviate) Sedation Miosis Pruritis
Triad of opioid overdose
Coma, respiratory depression, pinpoint pupils.
Does tolerance to opioids affect safety?
NO! Even if a person has become tolerant to the drug, it is still toxic at the same doses it was before.
More potent than morphine- associated with less pruritis, HoTN, and bronchoconstriction. Considered safer for those with renal impairment.
Hydromorphone (Dilaudid)
Opioid C/I’s
Head Injury Impaired Pulmonary Function Impaired Renal Function Impaired Liver Function Pregnancy Addison's Disease or Hypothyroidism Partial Agonists (used in combo with) Substance Abuse History Drug Interactions- Serotonin Syndrome w/ MAOI's
Crushing, dissolving, or chewing this drug can cause rapid release and absorption and a potentially fatal dose.
Morphine
More potent than morphine, very similar in effect to Hydromorphone. Also associated with less histamine release so less pruritis, HoTN and bronchoconstriction.
Oxymorphone
Used in combo with an anesthetic for post-op or labor pain
Fentanyl
Used as primary general anesthetic for cardiac surgery and patients with impaired cardiac function
Fentanyl
Blocks K+ channels and can lead to long QT syndrome and potentially fatal arrhythmias.
Methadone
Hepatic demethylation to toxic metabolite that can cause potentially fatal neurotoxicity, CNS hyperactivity and seizures. Cannot be reversed with Naloxone.
Meperidine (Demerol)
metabolized to nomeperidine
Avoid use in combo with MAOI’s, SSRI’s, tramadol or methadone- can cause potentially fatal serotonin syndrome.
Meperidine (Demerol)
Medium efficacy opioid analgesic combined with aspirin
…dan (i.e. Percodan)
Medium efficacy opioid analgesic combined with acetominophen
…cet (i.e. percocet, Darvocet, Ultracet), also Vicodin, Tylenol with codeine #3, Lortab
Combining medium efficacy oral opioid analgesics with aspirin, acetaminophen or ibuprofen allows for…
two separate mechanisms to treat pain, can use less of each.
Common source of prescription drug abuse
medium efficacy oral opioid analgesics.
“Poor metabolizers”- this drug doesn’t work for 7% of Caucasians, 3% of African Americans, 2% of Asians and 1% of Arabs.
Codeine
“Ultra- metabolizers”- this drug has abnormally increased affects and toxicity in 4-5% of US population
Codeine
“Hillbilly Heroin”- abuse of this drug is a significant social problem. Crushing pills disables slow release mechanism and causes a higher effective dose.
OxyContin
Moderate medium efficacy oral opioid analgesic between codeine and oxycodone. Good anti-tussive. Widely prescribed (more than any other opioid.)
Hydrocodone (dihydrocodeinone) Vicodin and others.
Can use to try and treat neuropathic pain.
Anti-depressants and Anti-convulsants.
