Cystic Fibrosis Flashcards
What is the most common CF mutation?
F508del
What is the incidence, inheritance pattern, and prognosis for cystic fibrosis (CF)?
- incidence is 1 in 3,000
- CF is an autosomal recessive genetic disease
- Average life expectancy is 61 years
- Mother and father have to carry a CF gene
- Every time they mate, there is a 25% chance the offspring will have CF
Which test is confirmative for the diagnosis of CF?
- Sweat chloride test
- > 60 mEq/L
List the CFTR modulator medications:
- Kalydeco (ivacaftor)
- Orkambi (ivacaftor/lumacaftor)
- Symdeko (tezacaftor/ivacaftor)
- Trikafta (elexacaftor/tezacaftor/ivacaftor)
- Alyftrek (vanzacaftor/tezacaftor/deutivacaftor)
Which CFTR modulator makes hormonal contraceptives less effective?
- Orkambi (ivacaftor/lumacaftor)
- Due to the lumacaftor
- Lumacaftor is also a strong CYP3A inducer
Which CFTR modulator is once daily dosing?
Alyftrek (vanzacaftor/tezacaftor/deutivacaftor)
What is the general mechanism of ivacaftor and deutivacaftor?
They help keep the CFTR channel open which improves the regulation of salt, water, and chloride – ultimately thinning out mucus.
What is the general mechanism of lumacaftor, tazacaftor, elexacaftor, and vanzacaftor?
They all increase the CFTR available at the surface
Which agents can be used for maintenance lung treatment/airway clearance therapy?
- Dornase alfa
- hypertonic saline
- Mannitol
Which drugs are used for their anti-inflammatory properties?
- azithromycin
- ibuprofen (high dose)
Ibuprofen dose is 20-30 mg/kg BID
What therapies are NOT recommended for CF?
- inhaled corticosteroids
- leukotriene modifiers (montelukast)
- oral corticosteroids
How is albuterol used in CF management?
Albuterol is a short-acting beta agonist that is used to open up airways prior to airway clearance therapy and to decrease bronchoconstriction prior to inhaled hypertonic saline.
Which pulmonary function test do we mainly use to assess how patients are doing for CF?
- FEV1
- Forced expiratory volume in one second
What are the primary pathogens causing pneumonia in patients with CF?
- MSSA
- MRSA
- pseudomonas aeruginosa
- h. flu
- klebsiella pneumonia
- e. coli
If a CF patient has pneumonia from MRSA what are the empiric IV therapy options?
only single coverage is needed
- vancomycin
- linezolid
- tetracycline
- TMP/SMX
- clindamycin
If a CF patient has pneumonia from MSSA what are the empiric IV therapy options?
only single coverage is needed
- cefazolin
- ampicillin/sulbactam (Unasyn)
- coverage by anti-pseudomonal B-lactam
Anti-pseudomonal B-lactams:
- ticarcillin
- piperacillin
- ceftazidime
- carbapenems (except erta)
If a CF patient has pneumonia from pseudomonas what are the empiric IV therapy options?
Use two different MOAs
- piperacillin/tazobactam or
- imipenem-cilastin or
- ceftazidime or
- meropenem or
- cefepime
WITH
- tobramycin or amikacin
If pt has history of pseudomonas within the last 5 years, cover it even it it doesn’t grow in current cultures
How are the kinetics of beta-lactams altered in CF patients?
- increased renal and non-renal clearance
Use max dose at shortest interval (q 6-8 h in the hospital or q8h at home) or use prolonged infusion
How are the kinetics of aminoglycosides changed in CF patients?
- increased Cl and Vd (0.3L/kg)
Initial dose –> 10-12 mg/kg/dose q24h
How are the kinetics of quinolones changed in CF patients?
no significant change
What drug is recommended for initial pseudomonas eradication in CF patients even if they are not symptomatic?
What is the dose?
- Tobramycin inhaler (TOBI)
- 300 mg IH BID
- one 28 day course
Can also be used for suppression therapy for patients with chronic pseudomonas
Which drug is given for chronic pseudomonas in CF patients who can’t tolerate tobramycin?
What is the dose?
- Aztreonam (Cayston)
- 75 mg IH TID
Big hassle between cleaning and administration time
What are the dosing recommendations for the pancreatic enzymes?
- typically start with 1,000 units of lipase/kg/meal
- range is 500 to 2,500 units of lipase/kg/meal
- Do not exceed 10,000 units of lipase/kg/day
What are the monitoring parameters for pancreatic enzyme replacements?
- number of stools per day
- fat content of stools
- growth/weight
- fat soluble vitamins (ADEK)
