Acute Pain Flashcards
Somatic pain types
Superficial; from skin, subs tissue, mucous membranes
Deep; Muscle, tendons, joints or bones
Visceral pain types
Parietal; localized to the area around the organ; sharp/ stabbing
Referred Pain; cutaneous pain resulting form patters of embryo logic developments and migration of tissues and the convergence of visceral and somatic afferent inputs into the cns
Red Flags of pain
Pain that wakes pts up
Immunosuppressive
Severe or progressive neurological deficit
Cold, pale mottled or cyanosis limb
New bowel/ bladder dysfunction
Severe and pain or signs of shock/ peritonitis
Who defined pain as an emotional experience rather than a sensory one
Plato
Who explained the degree of plain associated with the degree of tissue injury
Rene Descartes “specificity theory of pain”
Who came up with the gate control theory of pain
Ronald Melzack and Patric Wall
In the substantia gelatinousa
Inflammatory mediators that contribute to pain
Peptides = bradykinin
Lipids = prostaglandins
Neurotransmitters = serotonin
Four elements of pain processings
transduction = noxious stimuli concerted to A&P
Transmission= AP is conducted through the nervous system
Modulation = pain transmission alters afferent neural transmission (gate control)
Perception- integration of painful input into somatosensory and lambic contrices
Allodynia
Pain from a stimulus that doesn’t normally evoke pain (thermal or mechanical)
Hyperalgesia
An exaggerated response to a normal painful stimulus.
What medication can cause hyperalgesia
Remifentanil (use with ketamine because its primary treatment of hyperalgesia)
Neuropathic pain
Complete denervation of a body part does result in numbness, the hallmark ‘negative” symptom of neuropathy. Yes nerve trauma and disease are also frequently associated with ‘positive’ symomtoms and signs.
Pain coming from the nerve itself
My receptor responses
Analgesia, resp depression, euphoria, reduced GI motility
kappa receptors response
Analgesia, dysphasia, psychosis, delusion/ delirium, mitosis, resp depression
Delta Receptors Response
Analgesia
Codeine compared to morphine
More reliably absorbed orally than morphine
Codeine metabolism
Metabolized by P450 CYP 2d6 10% of admin dose is demethlated in liver to morphine
Remainder demethlyated to inactive norcodeine CYP3A4
Who do we avoid codeine in?
CHildren less than 12 lack maturity of the enzyme and can experience side effects w/out analgesia
COdeine adult dosing
15-60 mg q4 max 360/day
Tramadol
Synthetic opioid that is a combo of morphine and codeine
Use for long and short term pain when we are trying to avoid a true opioid
Receptors; mu kappa and delta
Tramadol metabolism
Cape 2d6 and 2A4 to active metabolite that is 2-4 x as potent as the OG
Tramadol potency and onset and T1/2
1/5-1/10 the potency of morphine
Onset 1-2 hrs
T1/2= 6.3 for Tramadol and 7.4 for metabolite
Tramadol contraindications
Sz pts
High incidence of n/v
Morphine receptors
Mu 1 and mu2
Morphine metabolism
Metabolism is conjugation with glucuronic acid
Lipid soluble/ highly protein bound
Active metabolite
Morphine onset and peak and women vs men
IM = 15-30 min and peak effect in 45 min
Greater analgesia and slower onset in women (give less)
Oxycodone
Synthetic derivative ‘replaced morphine’
Name for long acting oxycodone
OxyContin (controlled release)
Oxycodone metabolism
Active metabolites
Mu and Kappa receptors
Cyp 2D6; excessive first pass effect
Dosing and timing for oxycodone
10-15 mg = 10mg of morphine
1 hr onset
3 hr half life (4.5 for CR)
Cr can last 12 hrs
Methadone
treatment for opioid addiction
potent and long duration of action
sporadic effects and get wide variety of effects
Where is methadone excreted
urine
metabolismed by 3A4 and 1A2 and 2D6 to inactive metabolite
What can increase cyp450
carbazepine - inducer
antiretroviral and grapefreuit juice- reducers
Dose for methadone
2.5-10 mg PO/IM/SC q 4-12 hr
takes awhile to get to steady state (takes about 10 days)
Fentanyl
synthetic opioid
high potency
rapid onset and fast offset
Detecting fentanyl
normeperidine can be detected in urine for up to 72 hrs
lungs serve as a large inactive reservoir
Hydromorphone potency and metabolism
3-5 x as potent as morphine when administered orally and 8.5 times as potent parenterally
liver metabolism
Hydrophrphone dosing
0.2-0.5 mg q 3-5 min
PO; 2-8 mg q4-6 hrs
Hydrocodone potency compared to codeine
6-8 x as potent as codeine
Most commonly abused perscription medications
oxycodone then hydrocodone
Hydrocodone metaboilsm
active metabolite hydromorphone
opioid that interacts with cardiac medications
hydrocodone
Buprenorphine
agonist antagonist of mu kappa and delta
analgesic or weaning for those with opioid abuse
Buprenorphine metaoblism
liver
can be IM or PO
Burprenorphine dose IM
0.3 mg = 10 mg of morphine
long half life 20-72 hr
Ibuprofen dose
200 mg 3 x daily
Celecobix dose
100 mg daily
Naproxen dose
220 mg twice daily
Diclofenac dose
50 mg twice daily
Anticonvulsant medications
Gabapentin (neurontin)
Phyenytoin (Dilantin)
Carbamazepine (tegretol)
Topiramate (topamax)
SKm relaxants
Baclofen
carisoprodol
Cyclobenzaprine (flexeril)
Methocarbamol (robaxin)
Tizanidine (zanaflex)
Morphine IV dose
2.5-15 mg
Morphine IM dose
10-15 mg
Morphine PO dose
40-60 mg
Codeine PO dose
15-60 mg
Hydromorphone IV dose
0.2-1 mg
mydromorphone IM dose
1-4 mg
Hydromorphone PO dose
1-4 mg
Fentanyl IV dose
20-50 mcg
Fent TM dose
200-1600 mcg
Fent TD dose
12.5-100 mcg
Hydrocodone PO dose
5-7.5 mg
Oxycodone Po dose
5 mg
methadone PO dose
2.5-10 mg
Tramadol PO dose
50-100 mg
Celecoxib PO dose
100 mg/d
Diclofenac PO dose
50 mg BID
NSAID
Mag sulfate dose
Loading 30-50 mg/kg
Maint 6-20mg/kg/hr
Lidocaine bolus dose
100 mg
Lidocaine gtt dose
1.3-3 mg/kg / hr
ketamine dose
0.25-0.5 mg/kg
Precedex loading dose
0.5mcg/kg over 10 min
precedex gtt dose
0.1-0.3mcg/kg/hr
gabapentin dose
200-300 mg
nicardipine dose
1-5 mg
Ephedrine dose
3-9mg
neo dose
10-30 mcg
