Ch 38: Cystic Fibrosis

Question 1

cystic fibrosis (CF)

Answer 1

thick mucus affects lungs, pancreas, liver, intestine. genetic disorder leads to abnormal transport of Cl, bicarb, and na ions across the epithelium.

Question 2

CFTR

Answer 2

CF transmembrane conductance regulator that is required to reg components of sweat, digestive juices, and mucus. gene is mutated in CF.

Question 3

symptoms

Answer 3

salty tasting skin, poor growth and poor wt gain despite food intake, thick and sticky mucus production, frequent lung infection, coughing, SOB. digital clubbing. digestiv sx like steatorrhea and malnutrition and failure to thrive.

Question 4

recommended order for maintstay meds

Answer 4

1) bronchodilator to open airways. 2) hypertonic saline via neb to mobilize mucus. 3) dornase alfa to thin mucus. 4) chest physiotherapy to mobilize mucus. 5) inhaled antibiotics to reduce inflammation and disrupt psa biofilm formation.

Question 5

common bacteria in CF

Answer 5

early in disease: staph, h flu. then psa.

Question 6

if infected with psa

Answer 6

intermittent: use 2 IV psa active drugs for synergy at higher doses to get into lung tissue for 2-4 wks.
chronic: use 1 inhaled agent 28 days on 28 days off to reduce freq of exacerbations

Question 7

dornase alfa

Answer 7

pulmozyme. via neb, do not mix with any other drug in neb. contraindication: hypersensitivity to chinese hamster ovary products. store ampules in fridge, protect from light.

Question 8

tobramycin inhaled

Answer 8

TOBI, Kitabis, Bethkis. ADRs: ototox, tinnitis, voice alteration, dizziness, bronchospasm, mouth and throat pain. doses should be 6 h apart. refrig recommended, can be room temp up to 28 d. protect from light. not studied in pts colonied with burkholderia cepacia. TOBI podhaler (inhaled powder) should be room temp caps.

Question 9

Aztreonam inhaled

Answer 9

Cayston inhaled via neb. ADRs: allergic rxns, bronchospams, fever, wheezing, cough, chest discomfort. doses should be at least 4 h apart. reconstitute with provided sterile diluent and give immed. refrig rec, room temp up to 28 d, protect from light.

Question 10

Azithromycin

Answer 10

zithromax. off label. PO. used to dec inflammation and reduce exacerbations. dosed by wt.

Question 11

nutrition in CF

Answer 11

high fat and cal dense diet d/t malabsorption and dec appetite. pancreatic enzyme replacement to improve digestion and nutritional status. PPIs with pancreatic enz (required for viokace only tab) to reduce sx of GERD. vitamin supplements (ADEK). insulin for CF-related DM.

Question 12

pancrelipase

Answer 12

creon, viokase (only tab), zenpep. warnings: colonopathy advancing to colonic strictures, mucosal irritation, hyperuricemia. ADRs: abd pain, flatulence, nausea, HA, neck pain. max dose: 10,000 units/kg/d or 2500 units/kg/meal. doses >6000 units/kg/meal are assoc with colonic strictures. contain amylase, lipase, protease. dose is individualized based on lipase component, doses are adjusted q3-4d until stools are normalized. porcine derived, not interchangeable. DR caps can be opened and sprinkled onto food (not dairy with high pH - need low pH), swallow immed. take with all meals and snacks (50% dose). skip missed doses.

Question 13

lumacaftor/ivacaftore

Answer 13

orkambi. with high fat containing food. respiratory events and HTN. hep adj. approved for pts >6 YO who are homozygous for CFTR F508del mutation (most common)

Question 14

ivacaftor

Answer 14

kalydeco. with high fat food. approved for pts >2 YO with 1 of 23 specific mutations of CFTR but not the homozygouse F508del mutation

Question 15

CF transmembrane conductance regulator potentiator

Answer 15

orkami and kalydeco. work at cellular level with cl transport defect. kalydeco inc time CFTR channels are open to augment cl transport. Orkambi corrects the CFTR folding effect to inc presence of protein at cell surface