Pharmacotherapeutics: cardiovascular, respiratory and renal disorders

In short

Pharmacotherapeutics of cardiovascular, respiratory and renal disease is the applied science of choosing, dosing, monitoring and de-prescribing drugs for the organ systems that account for the largest share of India's non-communicable disease burden. It links pathophysiology to drug selection using guideline evidence (ACC/AHA–ESC, GINA, GOLD, KDIGO) adapted to Indian practice (ICMR, Standard Treatment Guidelines, NLEM and the National Programme for NCDs). It is examined in Pharm.D years III–V, in PCI/Pharm.D residency vivas and in the Clinical Pharmacy papers of GPAT-style and university exams, and is the core competency tested in interviews for clinical pharmacist, medical-information, pharmacovigilance, medical-writing and MSL roles at Apollo, Fortis, AIIMS, CMC Vellore, Manipal, Cipla, Sun Pharma, Dr Reddy's and Novartis/IQVIA. Day to day it is used for renal dose adjustment, anticoagulation monitoring, inhaler counselling, drug–drug interaction screening and ADR reporting to the PvPI at IPC Ghaziabad.

Explained

Hypertension

• Definition (ACC/AHA 2017 and subsequent updates): normal <120/80; elevated 120–129/<80; stage 1 130–139/80–89; stage 2 ≥140/≥90. Older JNC 8 and several Indian/ESC documents still define hypertension as ≥140/90 — state which threshold you are using, as exam answers differ by source.
• Pathophysiology targets: cardiac output (HR, preload) and systemic vascular resistance; RAAS, sympathetic drive, renal sodium handling, endothelial dysfunction.
• First-line classes (any one or in combination): thiazide-type diuretics (chlorthalidone, indapamide > hydrochlorothiazide in outcome data), CCBs (amlodipine), ACE inhibitors (enalapril, ramipril), ARBs (telmisartan, losartan). Beta-blockers are not first-line unless there is a compelling indication (post-MI, HF, AF rate control, angina).
• Combination logic: A + C or A + D (A = ACEi/ARB, C = CCB, D = thiazide). Never combine ACEi with ARB or with a direct renin inhibitor — more hyperkalaemia and AKI, no benefit (ONTARGET, ALTITUDE).
• Compelling indications: diabetes/proteinuric CKD → ACEi or ARB; HF → ACEi/ARB/ARNI + beta-blocker + MRA + SGLT2i; post-MI → beta-blocker + ACEi; pregnancy → labetalol, methyldopa, nifedipine (ACEi/ARB/aliskiren are contraindicated — fetal renal damage).
• Resistant hypertension: BP above goal on three drugs including a diuretic at optimal doses; add spironolactone (PATHWAY-2), exclude non-adherence, NSAIDs, steroids, OCPs, sleep apnoea, renal artery stenosis, primary aldosteronism.
• Hypertensive emergency (BP very high with target-organ damage): IV labetalol, nitroglycerine, nicardipine, sodium nitroprusside (cyanide risk, use thiosulfate cover); lower MAP by ≤25% in the first hour. Urgency (no organ damage): oral agents over 24–48 h. Sublingual nifedipine is obsolete and unsafe.
• Class adverse effects: ACEi — dry cough (bradykinin), hyperkalaemia, angio-oedema, teratogenicity; ARB — same minus cough; amlodipine — ankle oedema, flushing, gum hyperplasia; thiazide — hypokalaemia, hyponatraemia, hyperuricaemia, hyperglycaemia, hypercalcaemia; beta-blocker — bradycardia, fatigue, bronchospasm with non-selective agents, masking of hypoglycaemia.

Heart failure, ischaemic heart disease and arrhythmia

• HF classification: HFrEF (LVEF ≤40%), HFmrEF (41–49%), HFpEF (≥50%); NYHA I–IV functional classes; ACC/AHA stages A–D.
• Four pillars of HFrEF therapy (GDMT): (1) ARNI (sacubitril/valsartan) preferred over ACEi/ARB — PARADIGM-HF; (2) beta-blocker proven in HF only — carvedilol, bisoprolol, metoprolol succinate; (3) MRA — spironolactone, eplerenone; (4) SGLT2 inhibitor — dapagliflozin, empagliflozin (DAPA-HF, EMPEROR-Reduced). Add loop diuretic for congestion (symptom relief, not mortality).
• Switch rule: stop ACEi 36 h before starting ARNI (overlapping bradykinin effect → angio-oedema). No washout needed from an ARB.
• Other agents: ivabradine if sinus rate ≥70 on maximal beta-blocker; digoxin for symptom/hospitalisation reduction and AF rate control (narrow index, target 0.5–0.9 ng/mL); hydralazine–isosorbide dinitrate; vericiguat in worsening HF. HFpEF: SGLT2i, diuretics, treat comorbidities.
• Drugs to avoid in HF: NSAIDs, non-dihydropyridine CCBs (verapamil, diltiazem) in HFrEF, thiazolidinediones, class I antiarrhythmics, high-dose saline.
• Acute coronary syndrome: STEMI vs NSTEMI/unstable angina on ECG and troponin. Immediate: aspirin 300 mg chewed, loading P2Y12 (clopidogrel 300–600 mg / ticagrelor 180 mg / prasugrel 60 mg), anticoagulation (UFH, enoxaparin, fondaparinux), sublingual nitrate, oxygen only if SpO2 <90%, statin.
• Reperfusion: primary PCI within 120 min of first medical contact; otherwise fibrinolysis within 12 h of symptom onset — streptokinase, alteplase or tenecteplase (TNK is the usual Indian hub-and-spoke choice; STEMI-India/Tamil Nadu and Kerala STEMI programmes use pre-hospital TNK then transfer).
• Secondary prevention ("ABCDE"): antiplatelet + ACEi, beta-blocker, cholesterol (high-intensity statin) + cardiac rehab, diet/diabetes control, education/exercise, smoking cessation. DAPT usually 12 months after ACS, shorter in high bleed risk; add a PPI if GI bleed risk (prefer pantoprazole/rabeprazole over omeprazole with clopidogrel — CYP2C19).
• Atrial fibrillation: rate control (beta-blocker, diltiazem, digoxin) or rhythm control (amiodarone, flecainide, ablation); stroke prevention by CHA2DS2-VASc — anticoagulate men ≥2, women ≥3; DOACs (dabigatran, rivaroxaban, apixaban, edoxaban) preferred over warfarin except in mechanical valves, moderate–severe rheumatic mitral stenosis (very common in India) and severe renal impairment, where warfarin remains standard.
• Dyslipidaemia: high-intensity statin (atorvastatin 40–80, rosuvastatin 20–40) for ASCVD; LDL-C goal <55 mg/dL in very high risk, <70 mg/dL in high risk (ESC/EAS; Lipid Association of India uses similar very-high and extreme-risk categories). Add ezetimibe, then PCSK9 inhibitor or inclisiran. Monitor myalgia/CK and ALT; fenofibrate for triglycerides >500 mg/dL; avoid gemfibrozil + statin (rhabdomyolysis).

Respiratory disorders

• Asthma (GINA): chronic eosinophilic airway inflammation with variable, reversible obstruction (FEV1 improvement ≥12% and ≥200 mL after bronchodilator). GINA no longer recommends SABA-only treatment for anyone.
  • Track 1 (preferred): as-needed low-dose ICS–formoterol as reliever at all steps; Steps 3–5 add maintenance ICS–formoterol (MART). Track 2: ICS whenever SABA is taken, or regular ICS with SABA reliever.
  • Step-up ladder: low-dose ICS → low-dose ICS–LABA → medium-dose ICS–LABA → add LAMA (tiotropium), assess phenotype, biologics (omalizumab for allergic, mepolizumab/benralizumab for eosinophilic, dupilumab); oral steroid is last resort.
  • Acute exacerbation: oxygen to SpO2 93–95%, repeated salbutamol ± ipratropium by nebuliser/spacer, systemic prednisolone 40–50 mg × 5–7 days, IV magnesium sulphate in severe cases; antibiotics are not routine.
• COPD (GOLD): persistent airflow limitation, post-bronchodilator FEV1/FVC <0.70; grades GOLD 1–4 by FEV1% predicted; groups A, B, E by symptoms (mMRC/CAT) and exacerbations.
  • Group A: a bronchodilator. Group B: LABA + LAMA. Group E: LABA + LAMA, add ICS if blood eosinophils ≥300 cells/µL or asthma overlap. ICS monotherapy is never appropriate in COPD.
  • Add-ons: roflumilast (FEV1 <50% with chronic bronchitis), azithromycin prophylaxis in selected ex-smokers, long-term oxygen if PaO2 ≤55 mmHg or SpO2 ≤88%, pulmonary rehabilitation, smoking cessation (varenicline, bupropion, NRT), influenza/pneumococcal/COVID vaccination.
  • Exacerbation: short-acting bronchodilators, prednisolone 40 mg × 5 days, antibiotic if increased sputum purulence (amoxicillin-clavulanate, doxycycline, azithromycin), NIV for hypercapnic respiratory failure.
• Inhaler devices and counselling: pMDI needs slow deep inhalation and 10-second breath-hold, with a spacer in children and the elderly; DPI needs a forceful deep breath and must be kept dry; rinse the mouth after ICS to prevent oral candidiasis; teach and re-check technique at every visit — poor technique is the commonest cause of apparent treatment failure.
• Other conditions in syllabus: allergic rhinitis (intranasal steroid + antihistamine), cough (treat cause; avoid codeine in children), pulmonary hypertension (sildenafil, bosentan, ambrisentan), pneumonia (CURB-65 driven antibiotics — detailed in the infectious-disease note), drug-induced lung disease (amiodarone, methotrexate, nitrofurantoin, bleomycin).

Renal disorders

• CKD (KDIGO) is staged by cause, GFR and albuminuria (CGA): G1 ≥90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 <15 mL/min/1.73 m²; A1 <30, A2 30–300, A3 >300 mg/g urine albumin:creatinine. CKD = abnormality present ≥3 months.
• Slowing progression: BP control (ACEi/ARB titrated to maximum tolerated dose if albuminuria), SGLT2 inhibitor (dapagliflozin/empagliflozin — DAPA-CKD, EMPA-KIDNEY), finerenone in diabetic CKD, glycaemic control, sodium and protein moderation, avoid nephrotoxins. Expect an acute eGFR dip ≤30% after starting ACEi/ARB or SGLT2i — do not stop for that; stop if >30% or hyperkalaemia.
• Complications and their therapy:
  • Anaemia — iron repletion first (ferritin, TSAT), then ESA (erythropoietin, darbepoetin) or an HIF-PH inhibitor (desidustat/roxadustat, both marketed in India); target Hb ~10–11.5 g/dL, never normalise.
  • CKD-MBD — phosphate binders (calcium acetate; non-calcium sevelamer, lanthanum), active vitamin D (calcitriol, alfacalcidol), calcimimetic (cinacalcet) for secondary hyperparathyroidism.
  • Metabolic acidosis — oral sodium bicarbonate when HCO3 <22 mmol/L.
  • Hyperkalaemia — calcium gluconate for ECG changes, insulin–dextrose, salbutamol nebulisation, then potassium binders (calcium polystyrene sulphonate, patiromer) and dialysis.
• AKI (KDIGO): Stage 1 — SCr rise ≥0.3 mg/dL in 48 h or 1.5–1.9× baseline or urine output <0.5 mL/kg/h for 6–12 h; Stage 2 — 2.0–2.9× baseline; Stage 3 — ≥3× baseline, SCr ≥4.0 mg/dL, RRT or anuria ≥12 h. Classify as pre-renal, intrinsic (ATN, AIN, glomerular) or post-renal.
  • Management: treat the cause, restore perfusion with balanced crystalloid, stop nephrotoxins and metformin/SGLT2i/RAAS blockers temporarily, avoid loop diuretics except for volume overload, dialysis for AEIOU — Acidosis, Electrolytes (refractory hyperkalaemia), Intoxication, Overload, Uraemia.
  • Common nephrotoxins to screen: NSAIDs, aminoglycosides, vancomycin (AUC-guided), amphotericin B, iodinated contrast, colistin, tenofovir, calcineurin inhibitors, cisplatin, and indigenous/heavy-metal containing preparations.
• Nephrotic syndrome: proteinuria >3.5 g/day, hypoalbuminaemia, oedema, hyperlipidaemia — corticosteroids, ACEi/ARB, statin, loop diuretic, treat thrombotic risk. Dialysis pharmacotherapy: heparin anticoagulation of the circuit, iron/ESA, phosphate binders, and dose supplementation after haemodialysis for dialysable drugs.
• Drugs requiring renal dose adjustment (high-yield list): aminoglycosides, vancomycin, most beta-lactams, fluconazole, acyclovir, levetiracetam, metformin (avoid if eGFR <30), DOACs, LMWH, digoxin, lithium, allopurinol, gabapentin/pregabalin, colchicine, atenolol, sitagliptin. Avoid: NSAIDs, nitrofurantoin at low eGFR, dabigatran at eGFR <30, metformin at eGFR <30, spironolactone with high potassium.

Monitoring, interactions and Indian regulatory practice

• Core monitoring parameters: BP, HR, weight and fluid balance, serum creatinine and eGFR, potassium and sodium, lipid panel, LFT/CK on statins, INR on warfarin, serum digoxin, Hb, phosphate, calcium, PTH, FEV1/PEFR and inhaler technique, exacerbation count.
• Warfarin: target INR 2–3 (2.5–3.5 for mechanical mitral valve). Interactions — amiodarone, metronidazole, fluconazole, cotrimoxazole, ciprofloxacin and NSAIDs increase effect; rifampicin, carbamazepine, phenytoin, vitamin K rich food decrease it. Vitamin K 1–10 mg (oral/IV) ± 4-factor PCC or FFP for major bleeding. DOAC reversal: idarucizumab (dabigatran), andexanet alfa (anti-Xa, limited availability in India).
• Frequent interactions: statin + clarithromycin/itraconazole/HIV PI (CYP3A4 → myopathy; prefer pravastatin/rosuvastatin); ACEi/ARB + MRA + NSAID ("triple whammy" → AKI and hyperkalaemia); digoxin + diuretic-induced hypokalaemia (toxicity); amiodarone + digoxin/warfarin (halve the doses); beta-blocker + verapamil (bradycardia, heart block); theophylline + ciprofloxacin/erythromycin (toxicity, narrow index 10–20 µg/mL).
• Indian regulatory and practice frame: Drugs and Cosmetics Act 1940 with Rules 1945 and the New Drugs and Clinical Trials Rules 2019; Schedule H/H1 prescription control (H1 covers specified antibiotics and others — the register must be kept 3 years); CDSCO approvals; Pharmacy Act 1948 and the PCI Pharm.D regulations; ADRs reported to PvPI (IPC Ghaziabad) on the suspected-ADR form; NLEM and DPCO price control cover most cardiovascular, respiratory and renal essentials; Ayushman Bharat PM-JAY and the free-drug programmes of Tamil Nadu, Rajasthan and Kerala drive generic selection; ICMR/NCD-programme Standard Treatment Guidelines are the audit reference in government hospitals.
• Pharmaceutical care process: collect → assess → identify drug therapy problems (indication, effectiveness, safety, adherence) → care plan with goals → follow-up; document as a SOAP note; medication reconciliation at admission, transfer and discharge; patient counselling on salt/fluid restriction, daily weights, inhaler use, INR diet and nephrotoxin avoidance.

Key points

• Four pillars of HFrEF — ARNI + beta-blocker + MRA + SGLT2 inhibitor; diuretics treat symptoms, not mortality.
• ACEi 36-hour washout — mandatory before sacubitril/valsartan to avoid angio-oedema.
• A + C or A + D — the preferred antihypertensive pairings; never ACEi with ARB.
• Compelling indication rules class choice — diabetic proteinuria → ACEi/ARB; AF/post-MI → beta-blocker; pregnancy → labetalol/methyldopa/nifedipine.
• Hypertensive emergency — reduce MAP by no more than about 25% in the first hour; sublingual nifedipine is obsolete.
• CHA2DS2-VASc — anticoagulate at ≥2 (men) or ≥3 (women); rheumatic mitral stenosis and mechanical valves still need warfarin, not a DOAC.
• ACS first dose — chewed aspirin 300 mg plus a loading P2Y12 plus anticoagulant; PCI within 120 min, else fibrinolysis within 12 h.
• High-intensity statin — atorvastatin 40–80 mg or rosuvastatin 20–40 mg; check CK only if myalgia, routine CK screening is not needed.
• GINA abolished SABA-only therapy — every asthma patient needs ICS-containing treatment; ICS–formoterol is the preferred reliever.
• MART — maintenance and reliever therapy with one ICS–formoterol inhaler reduces severe exacerbations.
• ICS in COPD only with eosinophils ≥300/µL or asthma overlap; ICS monotherapy is never used in COPD.
• Spacer plus mouth rinse — improves lung deposition and prevents oral candidiasis; technique check at every visit.
• KDIGO CGA staging — cause, GFR (G1–G5) and albuminuria (A1–A3); eGFR alone is an incomplete answer.
• Allow an eGFR dip ≤30% after starting RAAS blockade or an SGLT2 inhibitor; stop above that or if potassium >5.5.
• AEIOU — the indications for urgent dialysis: acidosis, electrolytes, intoxication, overload, uraemia.
• Triple whammy — ACEi/ARB + diuretic + NSAID is a leading avoidable cause of hospital AKI.
• Target Hb 10–11.5 g/dL in CKD anaemia — correct iron first; normalising Hb increases stroke and death.
• Narrow-therapeutic-index drugs here — digoxin 0.5–0.9 ng/mL, theophylline 10–20 µg/mL, warfarin INR 2–3, vancomycin AUC24/MIC 400–600.

Formulas and examples

Example 1 — Cockcroft–Gault and renal dose adjustment. A 68-year-old woman, 55 kg, serum creatinine 1.8 mg/dL, is prescribed enoxaparin for NSTEMI.

• CrCl = [(140 − 68) × 55 × 0.85] / (72 × 1.8) = (72 × 55 × 0.85)/129.6 = 3366/129.6 = 26.0 mL/min.
• CrCl <30 mL/min → therapeutic enoxaparin is reduced from 1 mg/kg twice daily to 1 mg/kg once daily = 55 mg once daily subcutaneously, with anti-Xa monitoring if available.
• Also review: metformin must be stopped (CrCl <30), any NSAID stopped, and dabigatran would be contraindicated.

Example 2 — digoxin loading dose. A 60 kg patient with AF needs digoxin; Vd = 7 L/kg, target plasma concentration 1.0 ng/mL = 1.0 µg/L, oral bioavailability F = 0.7.

• Vd total = 7 × 60 = 420 L. Amount needed in body = 420 L × 1.0 µg/L = 420 µg.
• Oral loading dose = 420/0.7 = 600 µg (0.6 mg), given in divided doses (e.g. 0.25 mg, then 0.25 mg, then 0.125 mg at 6-hourly intervals) with ECG and potassium checks.
• If renal function is impaired, the loading dose is unchanged but the maintenance dose is reduced, because loading depends on Vd and maintenance on clearance.

Example 3 — LDL-C, risk category and statin choice. A 52-year-old man post-PCI: total cholesterol 212 mg/dL, HDL-C 38 mg/dL, triglycerides 180 mg/dL.

• LDL-C = 212 − 38 − (180/5) = 212 − 38 − 36 = 138 mg/dL.
• He is very high risk (established ASCVD) with an LDL-C goal <55 mg/dL, needing a reduction of (138 − 55)/138 = 60%.
• Atorvastatin 80 mg or rosuvastatin 40 mg gives roughly 50–55% LDL lowering, so ezetimibe 10 mg is added (a further ~20%); recheck lipids in 4–6 weeks, LFT at baseline, CK only if myalgia.

Example 4 — AKI staging and the triple whammy. A 70-year-old on ramipril and furosemide starts ibuprofen for knee pain. Baseline creatinine 1.0 mg/dL; after 4 days it is 2.4 mg/dL, urine output 20 mL/h at 60 kg.

• Ratio = 2.4/1.0 = 2.4× baseline → KDIGO Stage 2 AKI by creatinine. Urine output = 20/60 = 0.33 mL/kg/h, sustained <0.5 mL/kg/h — consistent with at least Stage 1 by output; the higher criterion governs, so Stage 2.
• Action: stop ibuprofen and furosemide, hold ramipril, give balanced crystalloid, check potassium and bicarbonate, review all doses against the new CrCl, re-challenge ramipril after recovery. No dialysis unless AEIOU criteria appear.

Example 5 — warfarin dose adjustment. A patient on warfarin 5 mg daily (35 mg/week) for a mechanical mitral valve has INR 1.6 (target 2.5–3.5) and has just finished rifampicin.

• INR is subtherapeutic; weekly dose is increased by about 15% → 35 × 1.15 ≈ 40 mg/week (e.g. 5 mg on five days and 7.5 mg on two days), recheck INR in 5–7 days.
• The enzyme-inducing effect of rifampicin takes 2–3 weeks to wash out, so the dose will need stepping back down with repeat INRs; bridging with LMWH is considered because a mechanical valve is high thrombotic risk.

Where it is used

• Hospital clinical pharmacy: ward rounds, renal dose-adjustment services and anticoagulation/TDM clinics at Apollo, Fortis, Manipal, CMC Vellore, AIIMS, Amrita and PGIMER, where Pharm.D graduates write SOAP notes and medication reconciliation records.
• Critical care and dialysis units: vancomycin and aminoglycoside dosing, CRRT dose supplementation, potassium and acid–base correction, ICU inotrope and vasopressor protocols.
• Pharmacovigilance and medical safety: ADR causality assessment (WHO-UMC, Naranjo) and PvPI reporting of ACEi angio-oedema, statin myopathy, NSAID-induced AKI; roles at IQVIA, Accenture, Cognizant, Novartis and Sun Pharma safety units.
• Medical affairs, medical writing and MSL roles: guideline-based content on ARNI, SGLT2 inhibitors, DOACs and triple-therapy inhalers for Cipla, Lupin, Glenmark, Dr Reddy's, USV, Torrent and Novartis.
• Community pharmacy and NCD programmes: inhaler technique demonstration, BP and adherence follow-up, salt and fluid counselling under the national NCD programme and Ayushman Arogya Mandirs; generic substitution within NLEM/DPCO limits.
• Clinical research and formulary work: protocol feasibility for cardiorenal trials, hospital drug and therapeutics committee submissions, antimicrobial and anticoagulant stewardship audits.

Interview questions

• Q: Why must an ACE inhibitor be stopped 36 hours before starting sacubitril/valsartan? A: Both raise bradykinin — neprilysin inhibition plus ACE inhibition sharply increases angio-oedema risk, so a 36-hour washout is mandatory; no washout is needed when switching from an ARB.
• Q: A patient's creatinine rises 20% a week after starting ramipril for diabetic nephropathy. Do you stop it? A: No — a dip up to about 30% is expected haemodynamic change and the drug is renoprotective long term; continue, recheck creatinine and potassium, and stop only if the rise exceeds 30% or potassium is above 5.5 mmol/L.
• Q: Which anticoagulant for AF with rheumatic mitral stenosis, and why? A: Warfarin with INR 2–3; DOACs were not studied in and have shown worse outcomes in rheumatic valvular AF, which is common in India.
• Q: Why is a beta-blocker no longer first-line in uncomplicated hypertension? A: Head-to-head and meta-analytic data (notably with atenolol) show less stroke protection and more new-onset diabetes than other classes; beta-blockers are reserved for compelling indications.
• Q: What is the "triple whammy" and why does it matter? A: An ACEi/ARB plus a diuretic plus an NSAID — the NSAID removes prostaglandin-mediated afferent dilatation while RAAS blockade removes efferent constriction, causing a steep GFR fall and a common, preventable hospital AKI.
• Q: Why is ICS monotherapy wrong in COPD but mandatory in asthma? A: COPD inflammation is neutrophilic and poorly steroid-responsive, and ICS alone raises pneumonia risk without bronchodilation; asthma is eosinophilic and ICS controls the inflammation that drives exacerbations and death.
• Q: How do you dose digoxin in renal impairment? A: Keep the loading dose (determined by volume of distribution) and reduce the maintenance dose (determined by clearance), aiming for 0.5–0.9 ng/mL with attention to potassium, since hypokalaemia potentiates toxicity.
• Q: Which classes reduce mortality in HFrEF and which only relieve symptoms? A: ARNI/ACEi/ARB, beta-blockers, MRAs and SGLT2 inhibitors reduce mortality; loop diuretics, digoxin and ivabradine improve symptoms or hospitalisation without a clear mortality benefit.
• Q: A diabetic on metformin is admitted with Stage 2 AKI. What do you do? A: Hold metformin (lactic acidosis risk when eGFR falls below 30), hold SGLT2 inhibitor and RAAS blockers, stop nephrotoxins, correct volume, and restart once renal function recovers.
• Q: Which statin do you choose for a patient on clarithromycin or itraconazole? A: Avoid simvastatin and atorvastatin (CYP3A4 substrates); use pravastatin or rosuvastatin, or withhold the statin for the short antibiotic course.
• Q: What counselling does a newly started MDI user need? A: Shake, exhale fully, seal lips, press and inhale slowly and deeply, hold breath 10 seconds, wait 30–60 seconds between puffs, use a spacer where possible, and rinse the mouth after an ICS dose.
• Q: How is hyperkalaemia with ECG changes treated, in order? A: IV calcium gluconate to stabilise the myocardium, then insulin with dextrose and nebulised salbutamol to shift potassium intracellularly, then a potassium binder or dialysis to remove it, while stopping the causative drugs.

Common mistakes

• Quoting a single hypertension threshold without naming the guideline — ACC/AHA uses ≥130/80, JNC 8 and several Indian/ESC sources ≥140/90.
• Using eGFR from CKD-EPI where the drug label is based on Cockcroft–Gault creatinine clearance, or forgetting the 0.85 female factor and the correct weight.
• Stopping a RAAS blocker or SGLT2 inhibitor for the expected small early creatinine rise, losing long-term renal protection.
• Reducing a loading dose in renal failure, or reducing only the frequency when the label requires a lower dose.
• Writing "SABA as needed" alone for asthma, or putting a COPD patient on ICS monotherapy.
• Prescribing a DOAC in rheumatic mitral stenosis, a mechanical valve or severe renal impairment.
• Forgetting to reconcile over-the-counter and AYUSH products — NSAIDs, decongestants, liquorice and heavy-metal-containing preparations alter BP and renal function.
• Reporting an ADR only in the case notes and not on the PvPI suspected-ADR form.

Related topics

Clinical pharmacokinetics and TDM · Pharmacotherapeutics: infectious diseases, oncology and endocrine disorders · Pharmacotherapeutics: neurological, psychiatric and gastrointestinal disorders · Clinical pharmacy practice: medication reconciliation and SOAP documentation · Pharmacovigilance and ADR reporting (PvPI) · Clinical research and biostatistics.