2.3 Respiratory & Infectious Disease Management

Respiratory & Infectious Disease Management

Pharmacists are critical in managing chronic respiratory diseases and ensuring appropriate antimicrobial stewardship. The landscape of asthma management has changed drastically with the introduction of SMART (Single Maintenance and Reliever Therapy). In infectious diseases, pharmacists guide empiric therapy for common outpatient infections, manage complex HIV antiretroviral regimens, and ensure compliance with directly observed therapy in tuberculosis.

1. Asthma and COPD Management

Asthma (GINA Guidelines)

The Global Initiative for Asthma (GINA) guidelines have revolutionized asthma treatment by shifting away from using Short-Acting Beta Agonists (SABA), such as albuterol, as monotherapy for reliever treatment. The regular use of SABAs is associated with down-regulation of beta-receptors, decreased bronchodilation, and increased airway hyperresponsiveness, leading to a higher risk of fatal exacerbations.

The new paradigm is SMART Therapy: GINA now recommends a low-dose Inhaled Corticosteroid (ICS) combined with formoterol (a Long-Acting Beta Agonist, LABA, with rapid onset) as both the daily maintenance controller and the as-needed reliever medication. Symbicort (budesonide/formoterol) is the primary agent used for SMART. When a patient experiences symptoms and takes a dose for relief, they simultaneously receive a dose of corticosteroid to treat the underlying airway inflammation, preventing the exacerbation from worsening.

• Track 1 (Preferred): Low-dose ICS-formoterol as needed (mild asthma) or daily maintenance plus as-needed (moderate/severe asthma).
• Track 2 (Alternative): Traditional daily ICS maintenance with an as-needed SABA. This is less preferred and requires strict adherence to the daily ICS.

Inhaler Technique: Pharmacists must counsel on inhaler technique. Metered Dose Inhalers (MDIs) require a slow, deep breath and coordination (or use of a spacer). Dry Powder Inhalers (DPIs) require a quick, forceful inhalation and no spacer can be used. Thrush is a common side effect of ICS; patients must rinse their mouth and spit after use.

COPD (GOLD Guidelines)

Chronic Obstructive Pulmonary Disease (COPD) management focuses on symptom relief and reducing exacerbations. Unlike asthma, bronchodilators are the cornerstone of COPD therapy, and ICS is reserved for specific severe phenotypes (especially those with high eosinophil counts).

• Group A (Low Symptoms, Low Exacerbation Risk): Any bronchodilator (SABA, SAMA, LABA, or LAMA).
• Group B (High Symptoms, Low Exacerbation Risk): LABA or LAMA, or a combination (LAMA + LABA).
• Group E (High Exacerbation Risk): LAMA + LABA combination is preferred. If blood eosinophils are ≥ 300 cells/mcL, triple therapy (LAMA + LABA + ICS) is indicated.

2. Outpatient Antimicrobial Stewardship

Appropriate antibiotic prescribing is heavily tested on the CPJE to combat antimicrobial resistance.

Community-Acquired Pneumonia (CAP)

For healthy outpatients with no comorbidities and no recent antibiotic use, the primary pathogens are Streptococcus pneumoniae, Mycoplasma pneumoniae, and Haemophilus influenzae. The first-line empiric treatment is:

• High-dose Amoxicillin (1 gram TID), OR
• Doxycycline, OR
• A Macrolide (Azithromycin) ONLY if local pneumococcal resistance to macrolides is < 25%. For patients with comorbidities (diabetes, heart, lung, or renal disease), coverage must be expanded using combination therapy (Amoxicillin/Clavulanate + Macrolide/Doxycycline) or monotherapy with a respiratory fluoroquinolone (Levofloxacin or Moxifloxacin).

Uncomplicated Urinary Tract Infections (UTIs)

The most common pathogen is Escherichia coli. First-line options include:

• Nitrofurantoin 100 mg BID for 5 days. (Contraindicated if CrCl < 30 mL/min. High risk of pulmonary toxicity with long-term use).
• Trimethoprim/Sulfamethoxazole (Bactrim DS) BID for 3 days. (Avoid if local resistance is > 20% or if the patient has a sulfa allergy).
• Fosfomycin 3 grams as a single dose. Fluoroquinolones (ciprofloxacin) are no longer recommended as first-line for uncomplicated UTIs due to severe collateral damage and black box warnings for tendon rupture, neuropathy, and CNS effects.

Skin and Soft Tissue Infections (SSTIs)

For purulent infections (abscesses), Community-Acquired MRSA (CA-MRSA) must be covered. First-line oral options include:

• Trimethoprim/Sulfamethoxazole
• Doxycycline
• Clindamycin (High risk for C. difficile infection; requires a D-test to rule out inducible resistance if erythromycin-resistant).

3. HIV Antiretroviral Therapy (ART)

HIV management relies on combining antiretroviral drugs from different classes to completely suppress viral replication and prevent resistance. The standard of care for treatment-naïve adults consists of a 3-drug regimen: an Integrase Strand Transfer Inhibitor (INSTI) combined with two Nucleoside Reverse Transcriptase Inhibitors (NRTIs).

Preferred Regimens (Single Tablet Regimens):

• Biktarvy (Bictegravir / Emtricitabine / Tenofovir alafenamide)
• Triumeq (Dolutegravir / Abacavir / Lamivudine). Requires HLA-B5701 testing before initiation. If positive, abacavir is absolutely contraindicated due to fatal hypersensitivity reactions.*
• Dovato (Dolutegravir / Lamivudine). This is a 2-drug exception, approved for initial therapy if HIV RNA is < 500,000 copies/mL and there is no Hepatitis B co-infection.

PrEP and PEP

• Pre-Exposure Prophylaxis (PrEP): Truvada (Emtricitabine/Tenofovir disoproxil fumarate) or Descovy (Emtricitabine/Tenofovir alafenamide). Descovy is not approved for individuals assigned female at birth at risk through vaginal sex. A negative HIV test must be documented prior to prescribing PrEP.
• Post-Exposure Prophylaxis (PEP): Must be initiated as rapidly as possible, optimally within 1-2 hours and absolutely within 72 hours of the exposure. The regimen consists of Truvada plus either Dolutegravir (Tivicay) or Raltegravir (Isentress) for a full duration of 28 days.

4. Tuberculosis (TB) Management

Active TB disease is treated with a combination of four drugs for an intensive phase of 2 months, followed by a continuation phase of two drugs for 4-7 months. The standard intensive regimen is RIPE:

• Rifampin: A potent CYP450 inducer. Causes red-orange discoloration of all body fluids (tears, sweat, urine) which can stain contact lenses. It can also cause flu-like symptoms and significant drug interactions with medications like oral contraceptives.
• Isoniazid (INH): Causes peripheral neuropathy. Pyridoxine (Vitamin B6) must be co-administered to prevent this. It also carries a black box warning for severe, sometimes fatal, hepatitis.
• Pyrazinamide: Can cause severe hyperuricemia (gout attacks) and hepatotoxicity. It requires renal dosing adjustments and should be avoided in acute gout flares.
• Ethambutol: Causes optic neuritis. Patients must undergo baseline and periodic visual acuity and red-green color vision testing. If vision changes occur, it should be discontinued immediately.

Directly Observed Therapy (DOT) is highly recommended for all patients with TB to ensure adherence and prevent multidrug-resistant TB (MDR-TB). In California, patients with active TB are reported to the local health department to ensure strict contact tracing and proper medication adherence for the public safety.