Opioid Analgesics

Question 1

Delta (OP1) Receptors

Answer 1

d1, d2

Expressed pre-synaptically. decreased Ca release. Increased K+ channel, and decreased NT release.

location: pontine nuclei, amygdala, olfactory bulbs, deep cortex.
function: analgesia, antidepressant effects, physical dependence

Question 2

Kappa (OP2) receptors

Answer 2

Expressed pre-synaptically. decreased Ca release. Increased K+ channel, and decreased NT release.

location: hypothalamus, periaqueductal grey, claustrum, spinal cold- substantia gelatinosa

Function: spinal analgesia, sedation, miosis, inhibiton of ADH release, dysphoria

Question 3

Mu receptor (OP3)

Answer 3

expressed post-synapticaly, increases K+ channel. inhibitory post synaptic potential

location: brain-cortex, thalamus, periacqueductal grey spinal cord-substantia gelatinosa, intestinal tract
mu1: supraspinal analgesia, physical dependence
mu2: respiratory depression, miosis, euphoria, reduced GI motility, physical depdendence
mu3: ?

Question 4

Morphine

Answer 4

Strong opiate

indication: analgesic used for pain.

SE: constipation (mu receptors in myenteric plexus), addiction, tolerance (receptor phos, decoupling from G protein, receptor internalization)

Overdose: respiratory depression.

increases viral load of Hep-C by supressing INF-alpha mediated immunity.

nalaxone is antidote

Question 5

Meperidine

Answer 5

kappa receptors

strong opiate

indication: used to relieve mild/severe pain (antispasmotic effects). used in biliary spasm/ renal colic.

Side effects: primarily due to metaoblite norpethidine. serotonin syndrom, seizure, dysphoria, tremor, respiratory depression.

vinds K+ channels, muscarinic receptors, DA transporters.

cannot be countered with nalaxone

Question 6

Hydrocodone

Answer 6

mu and delta receptor

Moderately strong.

similar to morhpine, perscribed for moderate to severe pain. mu and delta receptor. prevents coughing during operation.

SE: constipation. drowsiness, diziness.

Toxicity: LOC, sleepiness, col skin, seizures, respiratory depression.

Question 7

Codeine

Answer 7

mu receptor

Indication: pain with cough, diarrhea, IBS, narcolepsy.

SE: euphoria, itching, urinary retension, depression, constipation, increased complications in ED

active metabolite is morphine

Question 8

Pentazocine

Answer 8

(+) pentazocine is a delta agonist

(-) is a delta/antagonist

indication: relieve mild/moderate pain due to dental extraction.

SE: weakly antagonizes the analgesic of morphine and meperidine. hallucinations, psychomimetic effects, cardiovascular effects.

can cause necrosis and sepsis at site if it is frequently injected.

antagonizes the anelgesic effects of morphine and mepiridine

Question 9

Nalaxone

Answer 9

antagonist of mu, kappa, and delta receptors

reverses the sedation, hypotension, and respiratory depression. can reverse psychomimetic and dysphoric of pentazocine.

SE: change in mood, trembling, change in heart rhythm, blocks action of pain lowering endorphines. prevents depersonlaization disorder.

Question 10

Methadone

Answer 10

binds mu/delta (agonist) and glutamane receptors (antagonist)

opioid anelgesic similar to morphine. depresses cough center.

used to treat heroin/opioid addiction. less sevre withrawal symptoms