Pharm Chapter 14 Flashcards
Pain is:
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage
WHO Three-step analgesic ladder
Level 1- first choice for pain
Level 2- when pain is mild to moderate
Level 3- only use opioids when its moderate to severe pain
Pain can be treated by:
Medications, E-stim, TENS, massage, rehab, hot/cold packs
Types of Pain
nociceptive
neuropathic
malignant/cancer pain
acute vs. chronic pain
Synthetic Opiod
(fentanyl, methadone) are chemically derived in the lab
Natural Opiod
derived from poppy (morphine, codeine)
Semi-synthetic Opiod
(oxycodone, oxymorphone) are chemically modified natural opioids;
Which drug is considered the Gold Standard against which others are compared in pain management?
Morphine
What dosage froms do Opioids comes in?
pills, patches, IV, epidural, lollipops, lozenges, and PCA pumps
What are two types of doses for Opioids?
ATC: around-the-clock (chronic pain)
BTP- Break-through-pain (pain spikes)
Differentiate between narcotic vs opiates vs opioids?
Narcotic - describes side effect, not action of the drug (ie: sedation, stupor, reduced responsiveness)
Opiate - derived from opium
Opioid - encompassing term for all narcotic analgesic-like agents
Where are the opioid receptors in the body found?
Brain and spinal cord; also found in the GI tract and throughout the body but efficacy of opioids is due to their effects in the brain and spinal cord
What does the existence of opioid receptors imply?
existence of endogenous compounds
Name 3 endogenous opioid like substances:
Endorphins, enkephalines, dynorphins
Name the 3 types of pain receptors
Mu - important for pain relief (analgesia)
Kappa
Delta
Which pain receptor is most important to analgesia?
Mu, greatest analgesia when stimulated. ALSO greatest side effects (respiratory depression and constipation, ex: heroin OD) and relationship to addiction.
Agonist:
bind to the receptor and stimulate it (elicits response)
Antagonist:
blocks receptor response
Name two strong opioid agonists indicated for severe pain?
Fentanyl, hydromorphone, meperidine, methadone(used for treatment of addiction), morphine, oxymorphone
Name opioid agonists indicated for mild to moderate pain?
codeine, propoxyphene, hydrocodone, oxycodone
Name opioid mixed agonist/antagonists?
pentazocine (talwin), butorphanol (stadol), nalbuphine (nubaine)
Antagonists Examlples
(naloxone (narcan) Naltrexone (Vivitrol))
What is the mechanism of action of the opioids?
Inhibition of signaling afferent pain transmission to ascending pathways (inhibit from periphery to the brain signaling)
Activate descending pathways to reduce pain signaling to the periphery - called disinhibition
Explain the role of G proteins:
Second-messenger system that propagates a signal from external receptor into the cells to carry out an action
1) decrease Ca+ = decrease impulse propagation
2) decrease K+ = neuron harder to excite
3) inhibit adenylyl cyclase = decreased firing of post-synaptic neuron
What are the top medications taken by patients in PT?
Opioids and nonopioids analgesics - APAP, ASA, NSAIDS
Concerns with COX-2 inhibitors?
Cardiovascular risk - some of these agents were taken off the market by the FDA due to this risk. This is due to inhibition of prostaglandins that cause blood vessel dilation and inhibition of platelet aggregation
What type of pain are the opioid analgesics best suited to manage?
Moderate to severe, postoperative or chronic pain for oncology
What is the best route for administration of opioids?
PO (Lat: per oris - by mouth) for most, Intrathecal or epidural for post operative or severe intractable pain.
List 3 common side effects of opioids:
N/V, constipation, respiratory depression, decrease GI motility. Most of these side effects are temporary and resolve with continued use of the meds.
Addiction
seeks out and ingests certain substances for mood altering and pleasurable experiences. Continued use despite harm.
Tolerance
need for more drug to achieve the same therapeutic effect due to downregulation of receptors and blunted impact on G proteins. *Explain down regulation” Often begins to develop at 3 weeks and takes 1-2 weeks of drug removal to return to normal
Physical Dependence
onset of withdrawal symptoms in the drug is stopped. Begin 6-10 hours after last dose. Withdrawal symptoms typically peak at ~3 days and last ~5 days. Withdrawal symptoms are commonly the opposite of the opioids effects (hyperalgesia, diarrhea, anxiety, etc.) This is NOT psychological dependence or addiction.
Pseudoaddiction
occurs when a patient is exhibiting addiction-like behaviors but doing so not to achieve a high or abuse the opioids, but because their pain is severe and they are not well controlled
Name 3 symptoms of narcotic withdrawal
body aches, nausea, vomiting, tachycardia, sweating, hyperalgesia, anxiety, diarrhea
(Receptors must repopulate)
Impact on Physical Therapy?
Sedation, lack of coordination, optimal pain control will maximize the session.