natural opiates and opioid receptors Flashcards
action of opioids
1) gi-> reduced camp
2) rectyfing K channels-> hyperpolarization.
3) Calcium channel blockade.
morphine action
central:
1) analgesic- quick tolerance.
2) respiratory depression- quick tolerance.
3) anti-tussive
4) emetic
5) muscurinic blockade-> pinpoint pupil (no quick tolerance)
6) convulsions
7) truncal rigidty.
peripheral
1) uterine relaxation
2) increased hormone secretion-> adh and prolactin
3) constipation
4) biliary cramps
5) bradycardia+hypotension
6) urinary retention
7) pruritis and bronchoconstriction (morphine specific)
adverse
tolerance- quick tolerance to analgesic, sedative, respiratory depression and euphoric
slow tolerance to constipation and pinpoint pupil
dependence- withdrawl within 10 hours after dose-
acute- 9 days~ hallucigenic, attempted sucicide, anxious fear of death. increased secretion (sweat, salivation, vomit diarrhea etc).
chronic- hypotension, hypothermia, bradycarida and mydriasis.
indications for opioids
1) analgesic
2) sedative- anesthesia
3) anti-tussive
4) acute pulmonary edema- relief of dyspnea
5) diarrhea treatment
kinetics
1) morphine is given in many ways- IM, parental- iv, sublingual nasal and more.
metabolism- enters many tissue spaces- placenta, minimal BBB (alfentanyl is best)-
metabolized to morphine-3-glucorinad (causes zeisures) and M6G (causes analgesia).
excreted in urine
morphine prep
morphine hydrochloride- 2mg ~ iv or 10-15mg subcutaneous
morphine sulfate- orally, 100mg~
adverse
1) respiratory depression
2) vomit
3) constipation
4) sedation, mental clouding
5) ICP increased
6) apnea in newborns
7) urinary retenion
8) tolerance and dependce.
contra
1) lungs- asthma etc
2) liver kidney dysfunctions.
3) pregnancy
4) head injuries
codeine- weak opioid agonist
used as anti-tussive but dextrometorphan is a better alternative.
no dependece and long term can lead to codenism
