Loop diuretics Cardiology Diuretic · Furosemide, bumetanide
Block the Na-K-2Cl cotransporter in the thick ascending limb, producing the kidney's largest achievable natriuresis.
Uses, harms, pearls Major uses
Decongestion in heart failure Volume overload in renal and liver disease Adjunct in hyperkalemia and hypercalcemia Adverse effects
Hypokalemia and hypomagnesemia AKI from over-diuresis Ototoxicity at high IV doses Hyponatremia, gout flares Monitoring
Daily weight (the honest end point) Electrolytes and creatinine Urine output against a stated target Cautions
Anuria unresponsive to trial dosing Combined with other nephrotoxin patterns (the triple-whammy adds NSAIDs and RAAS blockade) Pearls
Gut edema slows oral absorption in decompensated failure: IV first, convert later. Diuretic response is judged in hours; a stated urine-output target makes 'not working' detectable tonight.
ACE inhibitors / ARBs Cardiology RAAS blockade · Ramipril, lisinopril; losartan, valsartan
Block angiotensin II formation (ACEi) or its receptor (ARB), dilating the efferent arteriole and damping aldosterone.
Uses, harms, pearls Major uses
Heart failure with reduced EF Hypertension Proteinuric kidney disease Post-infarction remodeling Adverse effects
Hyperkalemia Creatinine bump (expected small; investigate large) ACEi cough and rare angioedema Hypotension Monitoring
Potassium and creatinine 1 to 2 weeks after start or titration Blood pressure Cautions
Bilateral renal artery stenosis physiology Pregnancy Prior angioedema Sick-day rules: hold during vomiting, diarrhea, or dehydration Pearls
A 20 to 30 percent creatinine rise after starting can be hemodynamic and acceptable; doubling is not. The hyperkalemia case on this platform exists because of this class plus an NSAID; teach the combination, not just the drug.
Beta blockers Cardiology Beta-adrenergic antagonist · Metoprolol, bisoprolol, carvedilol
Block beta-1 (and variably beta-2/alpha) receptors: slower rate, reduced contractility, suppressed renin, lower myocardial oxygen demand.
Uses, harms, pearls Major uses
HFrEF (specific agents with mortality benefit) Rate control in AF Post-infarction Angina Adverse effects
Bradycardia and AV block Hypotension and fatigue Bronchospasm (nonselective agents in reactive airways) Masked hypoglycemia awareness Monitoring
Heart rate and pressure ECG when combined with other AV-nodal agents Cautions
Decompensated cardiogenic shock High-grade AV block without pacing Abrupt withdrawal (rebound) Pearls
In HFrEF the benefit is chronic: start low in stability, not during the wet decompensation. First-degree block plus a beta blocker plus AF rate control is how Wenckebach appears overnight; the medication list explains many rhythm strips.
Amiodarone Cardiology Class III antiarrhythmic
Multichannel blockade (potassium, sodium, calcium, beta): prolongs repolarization across the myocardium.
Uses, harms, pearls Major uses
AF rhythm control when structure limits alternatives Ventricular arrhythmias Adverse effects
Thyroid dysfunction both directions Pulmonary fibrosis Hepatotoxicity Photosensitivity and corneal deposits QT prolongation Monitoring
TSH and liver enzymes at baseline and periodically Consider baseline PFTs/imaging; symptoms drive re-imaging QTc on ECG Cautions
Interacts broadly (warfarin, digoxin) Iodine load confuses thyroid testing Pearls
The half-life is weeks: toxicity and interactions outlive the prescription. New cough or dyspnea on chronic amiodarone is pulmonary toxicity until excluded.
Direct oral anticoagulants Hematology Anticoagulant · Apixaban, rivaroxaban, dabigatran
Direct inhibition of factor Xa (apixaban, rivaroxaban) or thrombin (dabigatran); predictable kinetics without routine monitoring.
Uses, harms, pearls Major uses
Stroke prevention in nonvalvular AF VTE treatment and prevention Adverse effects
Bleeding (GI prominent with some agents) Accumulation in renal impairment Monitoring
Renal function at least annually and with illness No routine coagulation testing; specific assays exist when needed Cautions
Mechanical valves and moderate-severe mitral stenosis (warfarin territory) Severe renal impairment per agent Peri-procedural hold planning with a documented restart owner Pearls
A held anticoagulant is a decision with an expiry date; the melena consult case turns on exactly this. Normal INR and aPTT do not exclude DOAC effect.
Warfarin Hematology Vitamin K antagonist
Inhibits vitamin K epoxide reductase, depleting factors II, VII, IX, X (and proteins C and S).
Uses, harms, pearls Major uses
Mechanical heart valves Valvular AF Antiphospholipid syndrome Where DOACs are unsuitable Adverse effects
Bleeding Early transient hypercoagulability (protein C falls first) Skin necrosis (rare) Teratogenicity Monitoring
INR against an indication-specific target More often around any drug or illness change Cautions
Interacts with a large share of the formulary and with diet Reversal pathways (vitamin K, PCC) should be known before they are needed Pearls
The INR responds days after the dose that caused it; adjust to the trend, not today's number alone. In cirrhosis the INR reflects synthetic failure, not warfarin-style anticoagulation.
Insulin (inpatient) Endocrinology Hormone replacement
Drives cellular glucose uptake and suppresses ketogenesis and hepatic glucose output; shifts potassium into cells.
Uses, harms, pearls Major uses
Diabetes when oral agents pause in hospital DKA and hyperosmolar states Hyperkalemia (with dextrose) Adverse effects
Hypoglycemia (the chief inpatient drug harm) Hypokalemia during DKA treatment Monitoring
Glucose at defined times, not ad hoc Potassium during DKA and hyperkalemia protocols Cautions
Sliding-scale-only regimens chase rather than control NPO status changes the plan before it changes the order Pearls
In DKA, insulin fixes the acid, fluids fix the volume, and potassium vigilance keeps the treatment from becoming the danger. In hyperkalemia the glucose recheck after insulin-dextrose is part of the order, not an afterthought.
Metformin Endocrinology Biguanide
Reduces hepatic gluconeogenesis and improves insulin sensitivity; weight-neutral and hypoglycemia-sparing alone.
Uses, harms, pearls
Systemic corticosteroids Rheumatology Glucocorticoid · Prednisone, hydrocortisone, dexamethasone
Genomic suppression of inflammatory transcription: broad, powerful, and indiscriminate immunosuppression.
Uses, harms, pearls Major uses
COPD and asthma exacerbations Flares of autoimmune disease Adrenal insufficiency (replacement) Selected oncologic and neurologic emergencies Adverse effects
Hyperglycemia Delirium and insomnia Infection risk with masked fever Bone loss, myopathy, adrenal suppression with duration Monitoring
Glucose, especially in diabetics Bone protection planning on long courses Cautions
Never stop long-term steroids abruptly Stress dosing during acute illness for chronic users Pearls
Steroids raise the white count by demargination: a climbing WBC on prednisone is not automatically infection. Every steroid start deserves a planned stop; open-ended courses are how adverse effects accumulate.
Vancomycin Infectious Diseases Glycopeptide antibiotic
Inhibits gram-positive cell wall synthesis; the empiric MRSA drug.
Uses, harms, pearls Major uses
Suspected or proven MRSA infection Severe gram-positive sepsis pending susceptibilities Oral form only for C. difficile Adverse effects
Nephrotoxicity, dose and duration related Infusion reaction with rapid administration Ototoxicity rarely Monitoring
Levels per protocol Creatinine alongside every level Cautions
Dose adjusts to renal function and actual weight IV vancomycin does not treat C. difficile; oral does Pearls
The kidney injury cases on this platform are why every vancomycin order carries a creatinine shadow. De-escalate the moment susceptibilities allow; empiric is a phase, not a plan.
Ceftriaxone Infectious Diseases Third-generation cephalosporin
Beta-lactam cell wall inhibition with broad gram-negative and respectable gram-positive coverage; excellent CSF penetration.
Uses, harms, pearls Major uses
Community-acquired pneumonia Pyelonephritis Bacterial meningitis (with additions) Spontaneous bacterial peritonitis Adverse effects
Biliary sludging C. difficile risk as with all broad agents Cross-reactivity in severe penicillin allergy is lower than folklore suggests Monitoring
Clinical response and de-escalation review at 48 to 72 hours Cautions
Neonates (bilirubin displacement) Does not cover Pseudomonas, enterococci, or atypicals Pearls
Once-daily dosing without renal adjustment makes it the workhorse; knowing what it does NOT cover is the actual skill. In meningitis the drug is chosen for the CSF it can reach.
Inhaled bronchodilators Respirology Beta-2 agonist / antimuscarinic · Salbutamol, ipratropium, tiotropium
Relax airway smooth muscle via beta-2 stimulation (fast) or muscarinic blockade (slower, additive).
Uses, harms, pearls Major uses
Asthma and COPD, maintenance and exacerbation Adjunct potassium shifting in hyperkalemia (nebulized salbutamol) Adverse effects
Tremor and tachycardia Hypokalemia at high doses Paradoxical bronchospasm rarely Monitoring
Technique checks: most inhaler failure is technique failure Heart rate at escalating doses Cautions
Overuse of reliever without controller marks uncontrolled asthma Beta blockade blunts the effect Pearls
The 12 percent reversibility that defines asthma on PFTs is this drug's signature. Discharge without an inhaler technique check is a readmission plan.
Opioids (inpatient analgesia) Palliative Medicine Opioid analgesic · Morphine, hydromorphone; naloxone reverses
Mu-receptor agonism: analgesia, dyspnea relief, sedation, respiratory depression, gut slowing.
Uses, harms, pearls Major uses
Moderate to severe pain Dyspnea in palliative care Acute pulmonary edema historically (limited role) Adverse effects
Respiratory depression (rate before oxygen saturation) Sedation and delirium in the old Constipation, universal Nausea, urinary retention Monitoring
Respiratory rate and sedation scores after dose changes Bowel regimen from day one Cautions
Renal impairment accumulates active metabolites (morphine especially) Stacked sedatives multiply risk Naloxone location known before it is needed Pearls
The opioid gas in the Blood Gas Lab is the pharmacology lesson: acute respiratory acidosis with an untouched bicarbonate. An opioid order without a laxative order is half an order.
Proton pump inhibitors Gastroenterology Acid suppression · Pantoprazole, omeprazole
Irreversibly inhibit the parietal cell H+/K+ ATPase: profound, durable acid suppression.
Uses, harms, pearls Major uses
Peptic ulcer disease and bleeding GERD and erosive esophagitis Ulcer prophylaxis in defined high-risk settings Adverse effects
Generally well tolerated; long-term associations include hypomagnesemia, B12 reduction, C. difficile and fracture signals Monitoring
An indication review at every care transition Cautions
Reflex continuation without indication is one of medicine's commonest prescription errors Pearls
In upper GI bleeding the PPI supports, but endoscopy decides. Every discharge medication reconciliation should ask why the PPI is still there.