55. Cystic Fibrosis Flashcards
T/F: Cystic fibrosis is a curable disease
False
Cystic fibrosis is caused by a mutation in the gene for the protein _____ and this mutation causes abnormal transport of _____ ion across the epithelium, leading to thick, viscous secretions
Cystic fibrosis transmembrane conductance regulator (CFTR)
Chloride, bicarbonate, and sodium
CF causes thick viscous secretions which affect ____, causing _____
the lungs, pancreas, liver, and intestines
causes difficulty breathing, lung infections, and digestive complications
The avg life expectancy of a person with CF is ___ yo with more than 75% of pts being diagnosed by ___ yo
35-40
2 yo
Dx of cystic fibrosis
Newborn screening first 2-3 days after baby is born
Initial screening identifies risk and then sweat chloride test (“sweat test”) is performed to confirm (looking for high salt (chloride) in sweat)
S/sx of CF
salty tasting skin, poor growth and poor weight gain (despite adequate food intake), mucus production, frequent lung infections, coughing and SOB
Patients experience obstruction of pancreatic ducts causing steatorrhea (Fatty stools) and poor absorption of nutrients (including fat-soluble vitamins)
Clubbing of the fingers may be present
____ and failure to thrive can result if CF is not treated
Malnutrition
For treatment of lung complications from CF, correct order when administering inhaled medications is crucial to maximize absorption and effect. What is the order?
1) inhaled bronchodilators (e.g. albuterol) - opens the airway
2) Hypertonic saline (e.g. HyperSal) - mobilizes mucus to improve airway clearance
3) Dornase alfa (Pulmozyme) - decreases viscosity of (thins) mucus to promote airway clearance
4) Chest physiotherapy - mobilizes mucus to improve airway clearance
5) Inhaled abx - controls airway infection
Inhaled therapies are the foundation of treatment in CF. The drug is delivered directly to the lungs, resulting in _____
minimal systemic absorption (reduces risk of toxicity)
The most common organisms seen early in CF disease are ___ and ___, followed by ____ in adolescents and adults
Staphylococcus aureus
H. influenzae
Pseudomonas aeruginosa
Acute pulmonary exacerbations are characterized by an increase in _____
cough, sputum production with change in sputum color (greenish), SOB, and a rapid decline in FEV1
T/F: For intermittent infections caused by Pseudomonas, monothearpy aminoglycosides is recommended
False - 2 IV drugs are recommended potential synergy and prevent resistance
Includes aminoglycosides, beta-lactams, quinolones, and others that cover Pseudomonas aeruginosa
When treating intermittent infection, IV abx doses tend to be (smaller/larger) than normal to address altered PK in pts with CF
larger
What is the difference in abx use in intermittent vs chronic infection caused by psuedomonas CF?
Intermittent - 2 IV drugs
Chronic - inhaled abx, 28 days on and 28 days off
Azithromycin does not cover pseudomonas but why is it used in cystic fibrosis?
Disrupts biofilm formation by bacteria which can improve lung function and decrease exacerbations
Dornase alfa (Pulmoyzme) storage notes
Store ampules in the refrigerator (do not expose to room temp ≥ 24 hrs)
Protect from light
T/F: Dornase alfa (Pulmozyme) cannot be mixed with any other drug in the nebulizer
True
What are inhaled abx used in CF lung infections?
Tobramycin (TOBI solution for inhalation, TOBI Podhaler capsule for inhalation)
Aztreonam (Cayston solution for inhalation)
Side effects of tobramycin (TOBI, TOBI Podhaler, Bethkis, Kitabis Pak)
Ototoxocity, tinnitus, voice alteration, mouth/throat pain, dizziness, bronchospasm
Tobramycin (TOBI, TOBI Podhaler, Bethkis, Kitabis Pak) dosing schedule
On + off cycle (28 days on, 28 days off)
Dosed every 12 hrs, must be at least 6 hrs apart
Tobramycin (TOBI, TOBI Podhaler, Bethkis, Kitabis Pak) storage notes
TOBI, Bethkis, Kitabis: refrigeration recommended (can be kept at room temp up to 28 days); protect from light; do not mix with any other drug in nebulizer
TOBI Podhlaer: room temp in dry place; use with Podhaler device; do NOT swallow capsules
T/F: Tobramycin Podhaler capsules can be PO or nebulized in a special Podhaler device
Flase - do NOT swallow capsules, nebulizer only
Inhaled Aztreonam (Cayston) side effects
Allergic reactions (may be severe), bronchospasm, fever, wheezing, cough, chest discomfort
Inhaled Aztreonam (Cayston) dosing schedule
On + off cycle (28 days on, 28 days off)
Dosed every 8 hrs but must be at least 4 hrs apart
Inhaled Aztreonam (Cayston) storage notes
Refrigeration recommended, can be kept at room temp up to 28 days
Protect from light
Use with Altera nebulizer system
Why do most CF patients supplement their diet with pancreatic enzyme products (PEPs)?
Thick mucus in CF obstructs pancreatic enzyme flow, resulting in a lack of these enzymes reaching the GI tract and subsequent malabsorption (causes smelly greasy/oily stools)
PEPs help break down fat, starches, and protein
Pancrelipase is a natural produce harvested from ____ which contains a combination of _____
Porcine pancreatic glands
Lipase, amylase, and protease
PEPs are formulated to dissolve in the more basic pH of ___
duodenum
PEP is individualized for each pt and based on the ___ component
Lipase
PEP dosing is adjusted every ___ until stools are normalized
3-4 days
Max dosing of pancrelipase
Lipase ≤2500 units/kg/meal or ≤10,000 units/kg/day
Note: Doses >6,000 units/kg/meal are a/w colonic stricture
What are some examples of pancrelipase products
Creon
Viokace
Zenpep
Warnings pancrelipase
Fibrosing colonopathy advancing to colonic strictures (rare, higher risk with doses >10,000 lipase units/kg/day), mucosal irritation, hyperuricemia
Side effects pancrelipase
Abdominal pain, flatulence, nausea, HA, neck pain
Most PEP formulation is capsules. Which PEP formulation is the only PEP that is a tablet (non-enteric coated) and requires PPI?
Viokace
T/F: PEP formulations are not interchangeable
True
PEP administration timing
before or with all meals and snacks
High fat meals may require higher doses
Use 50% of mealtime dose with snacks
Can PEP capsules be opened to be sprinkled on soft food?
DR capsules with enteric coated microspheres/microtablets may be opened and sprinkled on soft, acidic foods (pH≤4.5) like applesauce
Avoid foods with high pH such as dairy
Note: do not retain capsule contents in mouth, swallow immediately with water to avoid mucosal irritation and stomatitis
PEP should be dispensed in original container except ___
Zenpep and some Creon strengths
The most common mutation in CFTR gene is ____
homozygous F508del mutation (2 copies of the same allele)
Which CFTR modulators are approved for homozygous F508del mutation+additional responsive mutations?
Lumacaftor/ivacaftor (Orkambi)
Tezacaftor/ivacaftor (Symdeko)
Which CFTR modulators are approved for heterozygous F508del mutation+additional responsive mutations??
Elexacaftor/tezacaftor/ivacaftor (Triakfta)
Which CFTR modulators are NOT approved for homozygous F508del mutation but approved for use in other responsive mutations?
Ivacaftor (Kalydeco)
Ivacaftor MOA
Increasing the time the CFTR channels remain open = enhances chloride transport activity
Lumacaftor, tezacaftor, elexacaftor MOA
Help correct CFTR folding defect, which increases the amount of CFTR dilvered to the cell surface
What type of diet is recommended to help with nutrition, normal weight and growth, increased energy needs and to prolong survival?
High fat and calorically dense diet
What vitamin supplements are required for CF patients?
Fat-solute vitamins A, D, E, and K
T/F: many pts with CF will eventually require metformin for treatment of CF-related DM
False - insulin
