pharmacology of pain

Question 1

what are the 3 receptor of opioid drugs

Answer 1

mu, delta, kappa

Question 2

main intracellular chemical effects of morphine

Answer 2

binds mu receptor
potassium moves extracellularly
calcium is blocked from entering

Overall: decreased excitability and decreased release of neurotransmitters

Question 3

it is important to remember that naloxone has a very…. because….

Answer 3

short half life

Question 4

what to do if pt becomes tolerant to an opioid (in terminal care, for example)

Answer 4

switch to a different opioid with lower tolerant

Question 5

whta are 1st, 2nd, 3rd line drugs for neuropathic pain

Answer 5

1) venlaxafine, duloxetine
tricyclic antidepressants
pregabalin, gabapentin
2) tramadol
capsaicin patches
lidocaine patches
3) botox
strong opioids

Question 6

moa lignocaine

Answer 6

block voltage gated na channels

Question 7

are general anaesthetics analgesics

Answer 7

no other than ketamine

Question 8

what causes trigeminal neuralgia

Answer 8

stretching or compression of trigeminal root fibres by branch of pica or aica

Question 9

symptoms of trigeminal neuralgia

Answer 9

Sudden, paroxysmal attacks of pain: electric shock-like, sharp, stabbing,
commonly unilateral, lasts from a few seconds to a few minutes

Cheekbone, nose, upper lip, upper teeth, sometimes extended
to lower lip, teeth, chin…

Question 10

tx of trigeminal neuralgia

Answer 10

Pharmacological treatment

carbamazepine (voltage-dependent sodium channel blocker)
baclofen (GABAB agonist)
gabapentin (disrupts activity of voltage-dependent calcium channels)
lamotrigine (voltage-dependent sodium channel blocker)
clonazepam (benzodiazepine)

Non-pharmacological treatment

Microvascular decompression
Radiofrequency thermocoagulation
Gamma knife radiosurgery