13 - Immunosuppressants Flashcards
Can you ratio immunosuppressant doses?
Yes
What is the recommended dose for cyclosporine?
10-15 mg/kg per day divided q12h (5-7.5 mg/kg/dose)
Does peak or trough of cyclosporine correlate more closely w/ AUC
Peak, but trough is easier to measure so thats what is used
When should you check cyclosporine levels after initiating a new dose?
Half life = 8-10 h, so check after 2 days
For cyclosporine, how do you go between oral and IV dosing?
IV = 1/3 of oral (BA = 30%)
What influences cyclosporine absorption?
Fat content of a meal
There is significant _____ variability in cyclosporine levels
Intra-person
When should trough levels be drawn for cyclosporine in relation to the last dose?
2h +/- 15 min post dose
Is cyclosporine likely to be dialyzed?
90% protein bound and large Vd (3-5 L/kg) so not likely
What determines target levels of cyclosporine and tacrolimus?
- Organ type
- Time since transplant
- Disease state
- Px history
What influences tacrolimus absorption?
Dietary fat and carbs
Does peak or trough of tacrolimus better correspond to AUC 24?
Trough is well correlated; only trough is drawn for IV dosing
For tacrolimus, how do you go between oral and IV dosing?
IV = 1/4 of oral (BA = 25%)
What is the mean clearance of tacrolimus?
0.06 L/h/kg
Are prograf and advagraf interchangeable? (both types of tacrolimus)
Not, have different dosing b/c advagraf ER
Initial dosing for tacrolimus
0.1-0.3 mg/kg/day divided q12h
Common drug interactions w/ calcineurin inhibitors
- CYP 3A4 inhibitors (increase levels) = azoles, macrolides, non-DHP CCB’s (more significant w/ CSA), grapefruit juice
- CYP 3A4 inducers (decrease levels) = rifampin, phenytoin, phenobarbital, St. John’s Wort
When should you restart tacrolimus after an acute overdose?
- Highly protein bound, so not dialyzed
- Must wait until level is in therapeutic range before restarting
