Opiod Analgesics (The Patient Satisfaction Score Drugs) Flashcards
High efficiency Agonists
Morphine Hydromorphone Oxymorphone Methadone Fentanyl Meperidine Heroin
Low-medium agonists
Codeine, oxycodone
Mixed agonist / antagonists and others
Buprenorphine, Tramadol
Pentazocine
Non - analgesic opiods
Dextromethorphan
Loperamide
Mu opiod receptors
Major receptor for drugs - analgesia, respiratory depression, euphoria, addiction
Kappa opiod receptors
Analgesia, sedation, dysphoria
DM receptor
Antitussive effects
Opiod analgesia
Increased threshold and tolerance, pain over perception. Better results for slow and nociceptive, rather than neuropathic pain.
Mechanism of opiod constipation
Mu opiod receptors on enteric nerves - decrease in propulsion, peristalsis, and secretion.
Common adverse effects
Constipation, nausea, vomiting, sedation, miosis, pruitis.
Triad of overdose
Coma
Respiratory Depression
Pinpoint pupils
If you have a high tolerance, should you get more opioids to get the same anesthetic effect?
NO! Therapeutic index is unchanged.
Contraindications
Head Injury pregnancy Impaired pulmonary, hepatic, renal function Hypothyroid Substance abuse history
Drug Interactions
MAOI’s - life threatening serotonin syndrome
Hydromorphone (“That drug that starts with ‘D’”)
More potent than morphine. Less histamine release - less pruitis, less hypotension/ bronchoconstriction. Better in renal disease because its metabolite is renally excreted.
Oxymorphone
More potent than morphine. Less histamine release - less pruitis, less hypotension/ bronchoconstriction. Better in renal disease because its metabolite is renally excreted.
Fentanyl
More lipophilic than morphine - 75-100x more potent. Admin via lollipop, lozenge, tablet, nasal spray. Short acting. Used in IV anasthesia
Methadone
Used to treat heroin addiction. Well absorbed PO. Long T 1/2.
LONG QT - Arrythmias
Meperidine (Demerol)
Less potent, short t 1/2. Metabolism is demethylation via CYP3A4 to toxic NORMEPERIDINE. This can lead to fatal neurotoxicity. Avoid in renal impairment / MAOI use.
Heroin
No therapeutic use, but has led to some good music.
Low-Medium efficiency opiod antagonists problems.
Combined with asprin or acetominophen - risk of liver toxicity. Often abused
Codeine
Prodrug - converted to morphine via demethylation via CYP2D6. metabolism is polymorphic - different effects on different patients. Also a good antitussive.
Oxycodone (percocet)
Highest efficiency - metabolized to oxymorphone by CYP2D6. Slow release version - oxycontin - crush it up to disable slow release and have a good time
Hydrocodone
Metabolized to hydromorphone via CYP2D6. Good antitussive. Less pruritis than codeine. Very popular
Mixed agonist-antagonist mechanism (general)
Agonists at kappa receptors - analgesic, dysphoria, hallucinations.
Antagonist at mu receptors - less respiratory depression, less euphoria
Pentazocine
mixed agonist-antagonist - not recommended parentral due to necrosis and sepsis.
Buprenorphine
mixed agonist-antagonist - sublingual due to 1st pass. Used to treat opiod dependence by antagonizing mu receptors.
Tramadol
Mixed opiod and NE reuptake inhibitor.
Tramadol risks
Seizures, avoid with MAOI’s - serotonin syndrome
Antitussive opiod
Dextromethorphan - active at DM receptor only.
Antidiarrheals
Loperamide
Loperamide
Immodium - reduces diarrhea by antagonizing gastric plexus. little BBB penetration.
Opiod Antagonist
Naxolone - Narcan - Competitive antagonist at ALL opiod receptors - used in overdose.
