Cystic Fibrosis Flashcards
Cystic Fibrosis - the basics
Incidence 1 in 3,000
Autosomal recessive genetic disease
Average life expectancy is 61 years
The basic problem
CF is caused by mutation in the transmembrane conductance regulator protein which is located on chromosome 7
With the CRTR channel being absent or reduced CL cannot get into the mucus like it usually does to thin the mucus and as a result sodium and water follow chloride leading to decreased amounts of water in the mucus and this causes a thickening of mucus that can get bacteria trapped in it and cause infection
Most common mutation is F508del
Newborn screen
Blood spot - used to test variety of diseases including CF
Immunoreactive trypsinogen - tests pancreatic function
Positive test NOT diagnostic
Diagnosis of CF
one or more sign/symptom + evidence of CFTR dysfunction
Sweat chloride test - >60mEq/L is diagnostic (norm <30mEq/L)
Genetic testing
Pancreatic function
Class I mutation
CFTR protein is absent and chloride transportation does not occur
Class II mutation
Little to no CFTR protein reaches the membrane and the CFTR proteins that do reach the membrane do not transport Cl properly
Most common
F508del mutation
Class III mutation
Normal number of CFTR protein at the membrane but they do not work properly
Class IV mutation
Normal number of CFTR protein at the membrane but only some of them work properly
Class V mutation
A reduced number of CFTR proteins at the membrane
CFTR that reaches the membrane transport appropriately
Kalydeco (Ivacaftor) - administration, monitoring, interaction
this is a CFTR potentiator
Great for class III and IV since it helps open the channels doors to allow chloride to transport
Take with fatty foods to increase level of drug
LFTs q3 months for 1 year then yearly
Eye exams - baseline and yearly for peds (increased risk of cataract)
Dose adjustment for hepatic impairment
CYP3A substrate (interacts with grapefruit juice, statins, cyclosporins)
Orkambi (Ivacaftor/lumacaftor)
Approved for those with 2 copies of the F508del homozygous
Take with fatty foods
AST/ALT/Bil Q3M for 1 year then yearly
Eye exam baseline and then yearly for pediatrics
Dose adjustment in hepatic impairment
Birth control drug interaction***- exam Q?
Lumacaftor CYP3A strong inducer
Ivacaftor CYP3A substrate
Side effect of chest tightness and SOB
Symdeko (tezacaftor/Ivacaftor)
Approved for those with homozygous (2 copies) of F508del mutation
Take with fatty foods
AST/ALT/Bil Q3M for 1 year then yearly
Eye exam baseline and then yearly for pediatrics
Dose adjustment in hepatic impairment
Ivacaftor CYP3A substrate
Trikafta (Elexacaftor/Tezacaftor/Ivacaftor)
Approved for patients with AT LEAST 1 copy of F508del
(if you miss orange tab dose by more than 6 hours take orange tablet when remember and skip evening blue tab)
Take with fatty foods
AST/ALT/Bil/Alk phose Q month for 6 months and then Q3M for 1 year then yearly
Eye exam baseline and then yearly for pediatrics
Dose adjustment in liver disease
Ivacaftor CYP3A substrate
Alyftrek (Vanzacaftor/Tezocaftor/ Deutivacaftor)
Same as Trikafta
Approved for patients with AT LEAST 1 copy of F508del
Take with fatty foods
AST/ALT/Bil/Alk phose Q month for 6 months and then Q3M for 1 year then yearly
Eye exam baseline and then yearly for pediatrics
Dose adjustment in liver disease
Ivacaftor CYP3A substrate
Airway clearance
Manual Airway clearance Technique
Therapy vest
Flutter, acapella
Huff coughing
Meta neb
Maintenance Lung treatment
Dornase Alfa: reduces viscosity and promoting clearance of mucus
Nebulized solution
Recommended in CF patients > or equal to 6 years old: can use in select cases for < 6 years old
Hypertonic saline nebulized solution - helps draw water into airway to clear mucus easier
Inhaled Mannitol (bronchitol): DPI, draws water into the airways to hydrate mucus, approved for 18 and up SE: Bronchospasm, hemoptysis, 5-15 minutes before use administer albuterol
Anti-inflammatory
Azithromycin
<40kg 250mg MWF
>40kg 500mg MWF
recommended in patients with chronic pseudomonas
Bronchodilators
Albuterol
- used before hypertonic saline nebulizer to open up airway and decrease bronchoconstriction prior to inhaled hypertonic saline
Pulmonary function tests
FEV1
FVC
FEF25-75
CF exacterbation
pathogens
S aureus (MSSA, MRSA)
P. Aeruginosa
H. Flu, Klebsiella
E. coli
Stenotrophomonas maltophilia
Burkholderia
CF exacterbation
Empiric IV therapy MSSA and MRSA
Only single coverage needed for both
MRSA - bactrim, clindamycin, vancomycin, tetracycline, linezolid
MSSA - cefazolin, unasyn, coverage by anti-pseudomonal beta lactam
CF exacterbation
Pseudomonas for IV therapy
Double coverage
Piperacillin/tazobactam,
imipenem-cilastatin
ceftazidime
meropenem
cefepime with tobramycin OR amikacin
If patient has history of pseudomonas always cover
Inhaled antibiotics - Tobramycin
Tobramycin
recommended for initial pseudomonas eradication - one 28 day course
suppression therapy in 28 day cycle for patients with chronic pseudomonas
Administration 15-20 minutes 300mg premade solution nebulizer
Podhaler 122mg = 4 capsules IH BID
Inhaled antibiotics - Aztreonam
Aztreonam 75mg IH TID
Used in patients with chronic pseudomonas
patients that cant tolerate tobramycin
