Pharm of Drugs for Acute Pain Flashcards
What is gravol’s MOA?
Antihistamine (H1) blocker
Can cross the BBB (makes you drowsy)
4 steps of pain processing
Transduction
Transmission
Modulation
Perception
How does modulation work?
By activating the skin mechanoreceptors, you stimulate Ad fibers which then can turn on the inhibitory interneuron to down regulate the pain signal
Allodynia vs hyperalgesia
Allodynia: normally not painful, now it hurts
Hyper: normally painful, hurts even more
COX 1 vs 2 pathways
1: constitutive, physiological path - produces thromboxane and prostaglandin
2: inducible pathway - produces prostaglandin
4 MOA of opioids
- Presynaptic: reduce excitatory transmitter release
- Postsynaptic: hyperpolarization of neurons by opening of K channels
- Activation of inhibitory descending pathways
- Activation of inhibitory enkephalin interneurons
M3G vs M6G
Morphine
M3G: no analgesia and neuroexcitatory
M6G: analgesic properties
What opioid activates mast cells?
Codein
Fentanyl pharm properties
Very lipophilic (crosses membranes very quickly)
Large volume of distribution
More effective and potent than morphine
4 opioid receptors
Mu
Kappa
Delta
Sigma
Mu opioid receptor effects
Analgesia Euphoria Resp depression Decrease GI motility Miosis Sedation Physical dependence
Multimodal analgesia
Give pain meds that act on different receptors
Naloxone (Narcan)
Opioid antagonist
Higher affinity than any of the opioids
Reverse depressed respiration from opioid overdose
Precipitate withdrawal symptoms
Prevent dependent individuals from experiencing a high from subsequent opioid use