Pain Management - Dosing

Question 1

Analgesic timelines for IV and PO. Relief vs peak effect vs wear off?

Answer 1

PO - relief in 30 min, peak effect 1.5-2 hrs, wear off 3-4 hrs
IV - relief in 5-10 min, peak effect in 30 min, lasts 2-3 hrs
not including methadone

Question 2

Dose escalation at peak effect for severe vs mild/moderate pain

Answer 2

inc by 25-50% for mild/moderate pain
inc by 50-100% for severe pain
not including methadone

Question 3

5 long acting formulations

Answer 3

1. MS Contin (long acting morphine)
2. Oxycontin (long acting oxycodone)
3. Hydromorphone
4. Hydrocodone
5. Fentanyl

Question 4

dosing frequency for long acting formulations? dosing for breakthrough relief?

Answer 4

dose q 12 hrs

breakthrough dose should be 10-15% of 24hr dose

Question 5

opiate tolerance

Answer 5

sustained opiate for 5+ days on an equivalent of 50mg morphine in 24hr period

Question 6

transdermal fentanyl dosing

Answer 6

in micrograms/hr

12.5, 25, 50, 75, 100

Question 7

transdermal fentanyl dosing frequency, analgesic effect when

Answer 7

relief in 18-24 hrs, dose q3days

Question 8

converting IV morphine to PO

Answer 8

multiply daiy dose x 3
2/3 is extended release (split into BID)
1/3 dose used for breakthrough pain

Question 9

if patient previously on opiates, how do you modify morphine dosing

Answer 9

add basal rate

Question 10

gold standard IV morphine dose

Answer 10

10mg

Question 11

PO morphine to fentanyl patch dosing

Answer 11

take 24 hr morphine dose and cut into half to get dose of patch

Question 12

Levy’s law

Answer 12

2:1 ratio for morphine in 24 hrs to # mcg/hr for fentanyl patch

Question 13

requirement before starting fentanyl patch

Answer 13

pt tolerated 50mg/day of morphine x 5 days

Question 14

Morphine PCA PO to IV basal dosing

Answer 14

take total PO morphine dose and divide by 3 to get IV formulation. divide into 24 hrs to get basal dose.

Question 15

loading dose calculation for morphine PCA

Answer 15

loading dose = 2 x demand

Question 16

how to calculate demand dose

Answer 16

demand = half of basal rate

Question 17

lock out parameters for morphine PCA

Answer 17

lock out in 10-15 min

Question 18

if pain is uncontrolled and you want to use short acting drug (aka modify morphine PCA settings) what do you change?

Answer 18

change the demand

Question 19

starting dose of methadone

Answer 19

5mg BID

Question 20

define pseudo-addiction

Answer 20

ex: sickle cell patient who has pain crises and needs higher doses of pain med for relief

Question 21

6 things you program into morphine PCA

Answer 21

1. concentration of drug (1mg/mL)
2. demand dose (1mg)
3. lockout (max frequency of button presses)
4. 1 or 4 hour limit (max amount of med in certain time frame)
5. loading dose
6. basal dose (continuous infusion)

Question 22

typical lockout for PCA pump

Answer 22

10-15 min

Question 23

does a opiate naive patient need a basal dose for a PCA pump?

Answer 23

no

Question 24

if patient is not getting relief from PCA, what do you adjust?

Answer 24

demand dose (what they get when they press the button)

Question 25

define cross tolerance

Answer 25

tolerance to effects of one drug produces tolerance to effects of other