Anelgesic Agents (Ch. 10 - Opioids)

Question 1

Absorption (drug movement from site of administration into blood stream)

Answer 1

IM or Subcutaenous: hydromorphone, morphine, mepederine
Oral: oxycodone, hydrocodone, codeine, tramadol, morphine
Transmucosal: lollipop fentanyl (fentanyl citrate)
Transdermal: Fentanyl patch
Intrathecal/spinal: fentanyl, morphine, hydrocodone

Question 2

Distribution (journey through blood stream to reach target cells and molecules)

Answer 2

IV: rapid half-lives, 5-20min
fentanyl and sufentanyl have a high lipid solubility = faster onset
morphine has a low fat solubility, slow onset. travles through BBB slowly

Question 3

Metabolism (modification by enzymes to render the drug ineffective)

Answer 3

liver by cytochrome P system. depends on liver blood flow

-except remifentanil, hydrolysis in plasma

Question 4

Elimination (removal from the body)

Answer 4

Kidneys!!
AKI, Kidney failure = prolong drug duration
kidney failure can lead to narcosis and ventilatory depression

Question 5

Pharmacodynamics:

Respiratory effects

Answer 5

decrease RR
increase VT
ineffective CO2 removal
Increases PaCO2 = shifting OxyHb curve to the Right
*rapid or high bolus= histamine induced bronchospasm
*rapid high doses= chest wall rigidity = prevent good BMV

Question 6

morphine
metabolism
elimination
onset
duration
side effects

Answer 6

gold standard to compare
metabolism by liver
eliminating by kidney
onset IM: 15-30min
Peak Effect IV: 15-30min
Duration 4 hours
side effects: histamine release

Question 7

Meperidine (demerol)

Answer 7

1/10th x as potent as morphine
synthetic

faster onset

Question 8

Hydromorphone (dilaudid)

Answer 8

semi-synthetic
5-7x more potent than morphine
duration: 4-5hours
elimination: kidneys

Question 9

Fentanyl

Answer 9

powerful synthetic
100x potency > morphine
rapid onset (high solubility) 1-3min
PE 5min
duration 30-60min

Question 10

Remifentanyl

Answer 10

ultra short 5-10min
Mu-receptor
250x potency > morphine
PE 1-3min
bradycardia & chest wall rigidity
metabolism: ester hydrolysis in plasma
\/ MAC by 60%

Question 11

Sufentanyl

Answer 11

/\ potent mu-receptor
50mcg/ml
10-15x potency > fentanyl
500-1000x potency > morphine!
/\ bradycardia and depress ventilation, chest wall rigidity

Question 12

Nalaxone (narcan)

Answer 12

REVERSAL FOR ALL OPIOIDS
0.25 mcg/kg/min
duration 30-60min
/\ SNS activity, pain, tachycardia, HTN, Pulm edema, VF