| Class | Drugs | Mechanism | Clinical Use | Adverse Effects |
|---|---|---|---|---|
| SABA (Short‑acting β₂ agonist) |
Albuterol (salbutamol), Levalbuterol | β₂‑adrenergic receptor agonist → ↑ cAMP → bronchodilation | Rescue inhaler for asthma/COPD exacerbations | Tachycardia, tremor, hypokalemia |
| LABA (Long‑acting β₂ agonist) |
Salmeterol, Formoterol, Vilanterol, Olodaterol | Same as SABA; longer duration (12‑24h) | Maintenance therapy for asthma (with ICS) and COPD | Same as SABA; never use as monotherapy in asthma (↑ mortality) |
| SAMA (Short‑acting muscarinic antagonist) |
Ipratropium | Blocks M3 receptors → ↓ cGMP → bronchodilation | COPD exacerbation; sometimes added to SABA in severe asthma | Dry mouth, urinary retention (rare with inhaled) |
| LAMA (Long‑acting muscarinic antagonist) |
Tiotropium, Umeclidinium, Aclidinium, Glycopyrrolate | Same as SAMA; 24‑h duration | First‑line maintenance for COPD; add‑on in severe asthma | Dry mouth, caution in narrow‑angle glaucoma |
| Methylxanthines | Theophylline, Aminophylline | Phosphodiesterase inhibition (↑ cAMP), adenosine antagonist | Rarely used (refractory COPD/asthma) | Narrow therapeutic index: seizures, arrhythmias, nausea |
| Class | Drugs | Mechanism | Clinical Use | Key Points |
|---|---|---|---|---|
| Inhaled Corticosteroids (ICS) | Fluticasone, Budesonide, Beclomethasone, Mometasone, Ciclesonide | Binds glucocorticoid receptor → ↓ inflammatory gene transcription | First‑line controller for persistent asthma; COPD with frequent exacerbations | Local: oral candidiasis, dysphonia. Systemic effects minimal at standard doses. |
| Systemic Corticosteroids | Prednisone, Methylprednisolone | Same as ICS, systemic effect | Acute asthma/COPD exacerbations; severe refractory disease | Short course (5‑7 days). Long‑term: osteoporosis, diabetes, adrenal suppression. |
| Leukotriene Receptor Antagonists (LTRA) | Montelukast, Zafirlukast | Blocks CysLT₁ receptor → ↓ bronchoconstriction, inflammation | Mild persistent asthma, exercise‑induced asthma, allergic rhinitis | Well tolerated. FDA black box warning: neuropsychiatric events (rare). |
| 5‑Lipoxygenase Inhibitor | Zileuton | Inhibits leukotriene synthesis | Asthma (rarely used) | Hepatotoxicity, CYP interactions. |
| Mast Cell Stabilizers | Cromolyn, Nedocromil | Prevents mast cell degranulation | Prophylaxis for exercise/allergen‑induced asthma | Very safe, but less effective than ICS. |
| Drug | Target | Indication | Notes |
|---|---|---|---|
| Omalizumab | Anti‑IgE | Moderate‑severe allergic asthma | SC injection q2‑4 weeks; risk of anaphylaxis |
| Mepolizumab, Reslizumab | Anti‑IL‑5 | Severe eosinophilic asthma | Reduces exacerbations; lowers eosinophil count |
| Benralizumab | Anti‑IL‑5Rα | Severe eosinophilic asthma | Depletes eosinophils via ADCC |
| Dupilumab | Anti‑IL‑4Rα | Moderate‑severe asthma, atopic dermatitis, nasal polyps | Blocks IL‑4/IL‑13 signaling; can cause eosinophilia |
| Tezepelumab | Anti‑TSLP | Severe asthma (broad phenotype) | Blocks upstream alarmin; effective regardless of eosinophils |
| Drug | Mechanism | Indication | Adverse Effects / Monitoring |
|---|---|---|---|
| Pirfenidone | Antifibrotic; inhibits TGF‑β, reduces fibroblast proliferation | Idiopathic Pulmonary Fibrosis (IPF) | GI upset, photosensitivity, LFT elevation |
| Nintedanib | Tyrosine kinase inhibitor (VEGFR, FGFR, PDGFR) | IPF, systemic sclerosis‑ILD, progressive fibrosing ILD | Diarrhea, nausea, LFT elevation, bleeding risk |
| Corticosteroids | Anti‑inflammatory / immunosuppressive | Sarcoidosis, hypersensitivity pneumonitis, COP, CTD‑ILD | Long‑term toxicity; taper to lowest effective dose |
| Immunosuppressants (Azathioprine, Mycophenolate, Methotrexate, Cyclophosphamide) |
Various; steroid‑sparing agents | CTD‑ILD, sarcoidosis, refractory HP | Myelosuppression, hepatotoxicity, infection risk |
| Biologics (Infliximab, Adalimumab, Rituximab) |
Anti‑TNF, anti‑CD20 | Refractory sarcoidosis, CTD‑ILD | Infection, infusion reactions |
| Setting | Regimen | Coverage |
|---|---|---|
| Outpatient, no comorbidities | Amoxicillin OR Doxycycline OR Macrolide (if low resistance) | S. pneumoniae, atypicals |
| Outpatient, with comorbidities | Amoxicillin‑clavulanate + macrolide OR Respiratory fluoroquinolone (Levofloxacin, Moxifloxacin) | S. pneumoniae, H. influenzae, atypicals |
| Inpatient, non‑severe | β‑lactam (Ceftriaxone, Cefotaxime) + Macrolide OR Respiratory FQ | Broad CAP coverage |
| Inpatient, severe (ICU) | β‑lactam + Macrolide OR β‑lactam + Respiratory FQ | Add MRSA coverage (Vancomycin) if risk factors |
| Drug | Mechanism | Major Adverse Effects |
|---|---|---|
| Isoniazid (INH) | Inhibits mycolic acid synthesis | Hepatotoxicity, peripheral neuropathy (give pyridoxine/B6), lupus‑like syndrome |
| Rifampin | Inhibits RNA polymerase | Orange body fluids, hepatotoxicity, potent CYP inducer (drug interactions!) |
| Pyrazinamide (PZA) | Unknown (requires acidic pH) | Hepatotoxicity, hyperuricemia (gout) |
| Ethambutol | Inhibits arabinosyl transferase | Optic neuritis (color blindness, visual acuity ↓) — reversible if caught early |
| Pathway | Drug Class | Examples | Notes |
|---|---|---|---|
| Nitric Oxide / cGMP | PDE5 inhibitors Soluble guanylate cyclase stimulators |
Sildenafil, Tadalafil Riociguat |
Contraindicated with nitrates. Riociguat also for CTEPH. |
| Endothelin pathway | Endothelin receptor antagonists (ERA) | Bosentan, Ambrisentan, Macitentan | Hepatotoxicity (bosentan), fluid retention, teratogenic (monthly pregnancy test). |
| Prostacyclin pathway | Prostacyclin analogs / IP receptor agonists | Epoprostenol (IV), Treprostinil (IV/SC/inhaled/PO), Iloprost (inhaled), Selexipag (oral) | Most potent vasodilators. Epoprostenol requires continuous infusion. |
| Drug | Mechanism | Notes |
|---|---|---|
| Nicotine Replacement Therapy (NRT) | Partial nicotinic agonist (reduces craving) | Patch, gum, lozenge, inhaler, nasal spray |
| Varenicline | Partial nicotinic acetylcholine receptor agonist | Most effective oral agent; monitor for neuropsychiatric symptoms (rare) |
| Bupropion | Norepinephrine/dopamine reuptake inhibitor; nicotinic antagonist | Also antidepressant; contraindicated in seizure disorder |
| Drug / Class | Interaction / Caution |
|---|---|
| Rifampin | Potent CYP inducer → ↓ efficacy of OCPs, warfarin, antiretrovirals, antifungals, immunosuppressants. |
| Macrolides (Azithromycin, Clarithromycin) | CYP3A4 inhibitors → ↑ levels of statins, warfarin, colchicine. Clarithromycin much stronger inhibitor than azithromycin. |
| Fluoroquinolones | QTc prolongation. Tendon rupture risk. Avoid with divalent cations (Ca, Mg, Al, Fe) — separate by 2‑4 hours. |
| LABA monotherapy in asthma | Without ICS, ↑ risk of asthma‑related death. Always combine LABA with ICS in asthma. |
| Beta‑blockers | Non‑selective (propranolol) can worsen bronchospasm. Use cardioselective (metoprolol, atenolol) with caution. |
| NSAIDs / Aspirin | Avoid in aspirin‑exacerbated respiratory disease (AERD / Samter's triad: asthma, nasal polyps, aspirin sensitivity). |
| PDE5 inhibitors + Nitrates | Profound hypotension — absolute contraindication. |