Cystic Fibrosis Flashcards
What is the minimum age for ivacaftor?
1 month
What is the minimum age for lumacaftor/ivacaftor?
1 year
What is the minimum age for tezacaftor/ivacaftor?
6 years
What is the minimum age for elexacaftor/tezacaftor/ivacaftor?
2 years
What is the main mutation that ivacaftor is indicated for?
G551D
T/F: Ivacaftor can be used to treat heterozygous F508del
FALSE: it can be used in these patients but it will not help the mutation
Which mutation is lumacaftor/ivacaftor approved for?
Homozygous F508del
Which mutation(s) is tezacaftor/ivacaftor approved for?
Homozygous F508del OR a CFTR mutation that is responsive to T-I
Which mutation(s) is elexacaftor/tezacaftor/izacaftor approved for?
At least 1 copy of F508del or a mutation that is responsive to T-I
What are possible side effects of CFTR modulators?
- Abdominal pain
- Diarrhea
- Rash
- Increased ALT/AST
- Increased blood creatine phosphokinase
- Rhinorrhea
- Headache
What should be monitored on CFTR modulator therapy?
- Baseline LFTs
- LFTS every 3 months for the first year, then annually
CFTR modulator pearls
- Take with fat containing meal
- Adjust dose with moderate-severe liver impairment
- Avoid grapefruit (CYP3A)
Which drugs have moderate CYP3A inhibition interactions with CFTR modulators?
Erythromycin, Fluconazole
How should ivacaftor dosing be changed with moderate CYP3A inhibition?
Once daily dosing
How should tezacaftor/elexacaftor dosing be changed with moderate CYP3A inhibition?
Take combination every other day alternating with ivacaftor alone
Which drugs have strong CYP3A inhibition interactions with CFTR modulators?
Clarithromycin, Itraconazole
How should ivacaftor dosing be changed with strong CYP3A inhibition?
Twice weekly dosing
How should tezacaftor/elexacaftor dosing be changed with strong CYP3A inhibition?
Twice weekly dosing
Which drugs are CYP3A inducers that should be avoided with CFTR modulators?
- Rifampicin
- Carbamazepine
- Phenobarbital
- Phenytoin
- St. John’s Wort
Safe bet treatments
Albuterol
Dornase alfa
Hypertonic saline 7%
Physiotherapy (vest)
Azithromycin
Vaccines (Flu/Covid)
Vitamins
Azithromycin in CF
- Used for anti-inflammatory properties
- M-W-F dosing
When should you use inhaled antibiotics?
Age at least 6 with persistent PA infection*
What should be done with home meds during acute exacerbation of CF?
Increase frequency (double)
CF exacerbation with MSSA?
Anti-staph penicillin/cephalosporin
CF exacerbation with MSSA and PA?
Aminoglycoside + 4th gen cefepime/ceftazidime
CF exacerbation with MRSA
Vancomycin or linezolid
CF exacerbation with MRSA and PA
Vancomycin/linezolid + aminoglycoside + beta-lactam (ceftazidime)
Antibiotic treatment duration
10-14 days
Reculture/adjust at 5-7 days with no improvement
Vancomycin monitoring
Goal 10-20 mcg/mL trough (AUC/MIC > 400)
Draw concentrations initially then every 3-7 days
