Pharmacotherapy of Respiratory, Gastrointestinal and Renal Disorders
Core concepts
For asthma, know the stepwise approach: inhaled corticosteroid as the backbone, with long-acting beta-agonist combinations; SABA-only treatment is no longer preferred. For COPD, bronchodilators (LAMA, LABA) are central, with ICS reserved for exacerbation-prone patients with eosinophilic inflammation. For gastro-oesophageal reflux, proton pump inhibitors are first-line; know that they should be taken 30–60 minutes before meals. For renal disorders, understand dose adjustment by creatinine clearance and the nephrotoxicity of NSAIDs, aminoglycosides and contrast.
Traps in questions
A common trap is using a LABA alone in asthma (unsafe without ICS). Another is prescribing an ICS in COPD without an indication. Watch for questions that ignore renal dose adjustment of renally cleared drugs (e.g., metformin, gabapentin, many antibiotics). Also, PPIs are often overused long-term - questions may ask when deprescribing is appropriate.
Worked rule of thumb
Use the "ICS backbone" rule for asthma: every patient with asthma should be on an ICS-containing regimen; add-on LABA only in combination. For renal dosing, estimate creatinine clearance with Cockcroft-Gault and adjust before prescribing. For a patient with asthma using SABA daily, the correct answer is to start or increase ICS, not to add another reliever.