Week 8 Ch 6: Opioid (Narcotics) Analgesics and Antagonists

morphine, codeine

what are some examples of agonists?

naloxone

what is an example of antagonists?

CNS

where does opioids act on?

peripheral endings

where do nonopioids act on?

enkephalins

stimulates delta receptor

endorphins

reduces pain and positively affects mood

dynorphins

stimulates the kappa receptor

mu

can produce analgesia when stimulated, respiratory depression

kappa

responsible for dysphoria - unease with life

delta

influence emotional responses

absorption

orally; occurs from the lungs, the nasal and oral mucosa, skin

distribution

undergoes variable first-pass metabolism in the liver or intestinal cell wall which reduces their bioavailability

metabolism

liver

excretion

kidneys

sedation and euphoria

kappa-receptor stimulation, may potentiate analgesic effect and decrease anxiety; euphoria can occur if larger doses or pain is suddenly removed; CNS excitation rarely occurs

cough suppression

antitussives, inhibiting cough reflex located in the medulla of brain - suppresses the resp system via CNS; lower than required dose for analgesia, least potent used (codeine); ig. dextromethorphan

gastrointestinal effects

inhibits contractions and motility (some opioids have constipation as side effect); treats diarrhea

substituting addict with oral opioid, cold turkey, methadone, administer naltrexone

what are 4 treatment options for addiction?

naltrexone

used as part of treatment for opioid or alcohol use disorder

opioid agonists

most commonly used opioids; analgesic reaction is related to their action on the mu and kappa receptors

morphine

prototype opioid agonist which other opioids are measured; parenterally - used to control postoperative pain; orally - used for cancer or terminal illness treatments

oxycodone

used alone or combined with aspirin or acetaminophen with increased analgesic effect but fewer adverse reactions; moderate-severe pain

codeine

most commonly used opioid in dentistry and is often combined with acetaminophen for oral administration; weak analgesic compared to other opioids

methadone

used primarily to treat any opioid addicts; used to either withdraw the patient gradually or maintenance; slower onset and longer duration of action; risk for dependence still exists

fentanyl

short-acting; parenterally administered agonist opioid analgesics; perioperatively or during general anesthesia