Lecture 22 - Opioids Flashcards
Opioid receptors are ____-_____ coupled receptors. These receptors are widespread throughout the body. In the CNS, opioid receptors can be found in many centers, including the one that processes ____, in the hypothalamus, and many others. They can also be found in the ____ horn of the spinal cord - so affects pain pathway. They are also present in the _____ nociceptors. Lastly, they affect smooth muscle, especially in the GI, so the main side effect in that regard is ______.
Pain
Dorsal horn
DRG nociceptors
Constipation
While Opioids are mainly used for pain control, they can also be used for _____ suppression (usually codeine) and control of diarrhea.
Cough
________ retention, ________, and ______ (pinpoint pupils) are the only peripheral effects of Opioids. The others are mediate by action on the CNS. Keep in mind the effects on the occulomotor complex can be blocked by _____.
Urinary retention
Constipation
Miosis
Atropine
While opioids block pain processing in the brain and transmission in the spinal cord, they also act on Perception, ______ reaction, and Visceral reaction to pain.
Emotional reaction
Mood alteration effects of opioids is attributed to activation of the _____ receptor in the ventral tegmental area of the hypothalamus.
Mu-receptor (Mu - Mood)
Opioids depress activity in the brainstem ____ ____ System (RAS), which controls activity throughout the brain. This causes sleepiness, but allows the person to be roused. Depression of this system also causes _______ depression, which is the cause of overdose death.
Reticular Activating System
Respiratory depression
Opioid activation of brainstem Chemoreceptor Trigger Zone (CTZ) stimulates _____ and ______.
Nausea and Vomiting
Generally speaking, does tolerance affect more so the central or peripheral effects of Opioids?
More so Central
_____-tolerance between different opioid drugs is partial and incomplete, so drugs can be rotated without consistently building tolerance.
Cross-tolerance
Among the opioids, ______ must be injected for it to have an effect bc it has very high “first-pass” metabolism in the liver.
Heroin
Opioids can cross the ______, so use during pregnancy is a big issue. Furthermore, there is not BBB for opiates in neonates, so use during labor can produce _______ depression in newborn.
Placenta
Respiratory
Heroin is Morphine with 2 acetyl groups (diacetylmorphine), and this makes Heroin much more ______ (lipo or hydrophilic?) than all other opioids. This means it can cross the ______ more so than the other opioids and build up higher concentrations of Morphine in the brain once it is metabolized there (higher concentrations than taking Morphine, itself.)
Lipophilic
BBB
______ has about 1/10th the strength of Morphine and can be taken for longer periods of time without developing physical dependence.
Codeine
Oxycodone is a codeine derivative. Longer lasting dosage has the trade name ______.
Oxycontin
Methadone is unique in that a single, isolated dose lasts about 6 hours, but a single dose after repeated use can last between ____ - ____ hours. This makes it good for chronic pain.
16-20 hours
