Opioids

analgesia, euphoria, sedation/drowsiness, repiratory depression, miosis, nausea/vomiting, antitussive

• increase resting tone of stomach, decrease motility, delay emptying time
• constipation - longitudinal muscle relaxation, circular muscle contraction
• spasm in biliary smooth muscle - opioids contraindicated if pt has gallstones
• other smooth muscle: increase tone and contraction, spasm of urinary tract

• act in hypothalamus to inhibit GnRH and CRH, decreasing plasma concentrations of LH, FSH, ACTH, and β-endorphin.
• release anti-diuretic hormone (ADH) - can lead to urinary retention.

• strong µ agonist for analgesia
• poorly absorbed after oral administration due to significant first-pass effect - given SC, IM, or IV - peak at 1.5hr, last 4hr
• Adverse rxn: shouldn't be taken w/ MAO I
• OD: pinpoint pupils, respiratory depression and coma

• moderate pain, cough
• similar duration of action as morphine
• 5-15% is converted to morphine
• good oral efficacy
• SE: constipation, nausea, itching, vomiting, drowsiness, dry mouth, urinary retention

• strong µ agonist
• heroin is diacetylmorphine: very lipophilic and rapidly enters the brain, but shorter half-life

• strong µ agonist
• similar to morphine w/ less nausea, vomiting
• half life: 12-16h

• strong µ agonist (no longer @ UCLA)
• antimuscarinic activity, less contraction of spincter of Oddi
• half life: 3h, metab half life: 15-20h
• MAO I - fatal interaction

• strong µ, K agonist
• 80x more potent than morphine, lipophilic
• also avail. transdermal patches

• treatment of diarrhea
• insoluble, remains in the gut
• atropine is added to prevent abuse

• immodium
• constipating effect
• substrate for p-glycoprotein, so it won't accumulate in the brain

• strong µ agonist
• longer duration of action, good oral bioavailability

• very weak analgesic, ASA may be more effective
• removed from market 2010

• synthetic codeine, weak agonist
• inhibition of uptake of NE, 5HT
• as effective as morphine for mild to moderate pain

• acts as a weak antagonist in the presence of µ agonists
• acts as a partial agonist at the µ receptor
• has κ agonist activity
• PO, less potent than morphine
• can produce dysphoria, anxiety; less vomiting than morphine
• less abuse potential

• partial agonist
• moderate to severe pain
• sublingual administration
• more potent than morphine @ low doses
• alternative to methadone
• slow dissociation from receptors

• opioid antagonist, treatment of overdose
• SC, IM, IV - poor oral bioavail, short half life!

• opioid antagonist
• similar to naloxone - more potent, longer acting
• can be taken PO

• centrally acting antitussive
• no analgesic, sedative, GI activity
• (codeine can also be used as an antitussive)