CF Pathogens & Antibiotic Therapy
What is the most common chronic bacterial pathogen found in CF lungs?
Pseudomonas aeruginosa
Classic symptom of a CF pulmonary exacerbation.
Worsening cough
Bronchodilator therapy often included to improve airflow during airway clearance.
Nebulized or inhaled short-acting beta-agonists (e.g., levalbuterol)
Common laboratory marker indicating acute infection or inflammation in CF exacerbations
WBC or CRP acceptable
Chronic CF therapy that may need to be held in patients with prolonged QTc
Azithromycin
In CF, IV antibiotic therapy is generally selected based on what information?
Prior CF respiratory cultures (pathogen-directed therapy)
Common symptom that indicates worsening lung function.
Shortness of breath / dyspnea
Nebulized mucolytic that reduces mucus viscosity in CF
Dornase alfa (Pulmozyme)
2 electrolytes often monitored due to dehydration or mucus clearance needs in CF
Sodium (Na) and Chloride (Cl)
Anti-inflammatory leukotriene antagonist therapy with limited evidence for acute exacerbations in CF.
Montelukast
If a CF patient’s MRSA PCR is negative, what is the recommended approach to vancomycin use?
Discontinue vancomycin
Sign indicating impaired airway clearance during an exacerbation.
Difficulty expectorating sputum / retained mucus
Hypertonic saline concentration commonly used in CF airway clearance
3% or 7%
During a CF pulmonary exacerbation, lack of improvement despite antibiotics should prompt repeat evaluation of this diagnostic test.
Respiratory culture and antibiotic susceptibilities
Drug class that should be avoided in CF patients due to worsened mucus clearance/GI motility
During a CF pulmonary exacerbation, antibiotics are typically continued until what clinical goal is achieved?
Resolution or significant improvement of symptoms and airway clearance
General supportive measures recommended during CF exacerbations
Oxygen supplementation, airway clearance, and hydration
Mechanical airway clearance devices often recommended in CF care.
Percussive/vibratory therapy devices (Aerobika, Acapella, Vest)
CF guidelines recommend reassessing treatment effectiveness using this combination of monitoring rather than labs alone.
Clinical symptoms and lung function
Pharmacists must monitor this in CF patients receiving repeated IV vancomycin courses due to risk of accumulation and toxicity.
Trough levels / AUC dosing
Which oral antibiotic is used chronically in CF for anti-inflammatory purposes rather than to treat acute infection?
Azithromycin
Measurement often used to assess severity of an exacerbation and guide therapy
FEV₁ (percent predicted)
To optimize mucus clearance during a CF pulmonary exacerbation, which sequence of therapies should be administered?
Bronchodilator → hypertonic saline → dornase alfa → mechanical airway clearance
Why CF patients often require higher or more frequent antibiotic dosing compared to non-CF patients.
Increased drug clearance and altered pharmacokinetics
Systemic therapy generally not recommended for routine use during CF exacerbations
Corticosteroids