How to use patterns for boards

Board questions rarely ask "what does drug X do?" Instead they describe a toxicity or a lab change and expect you to recognize the pattern. Learning patterns in groups — all P-450 inducers together, all pulmonary toxins together — makes recall faster than drug-by-drug lists.

workspace_premium Pattern first, mechanism second

Use a pattern to narrow the answer, then check it against the mechanism. A mnemonic without a mechanism breaks on a novel question; a mechanism without a pattern is slow.

Drug-name stems

Generic drug names follow naming conventions that encode the class.

StemClassExample
-ololβ blockerMetoprolol
-prilACE inhibitorLisinopril
-sartanAngiotensin II receptor blockerLosartan
-dipineDihydropyridine calcium channel blockerAmlodipine
-statinHMG-CoA reductase inhibitorAtorvastatin
-xabanFactor Xa inhibitorApixaban
-azoleAntifungal (ergosterol synthesis) or PPI (-prazole)Fluconazole, omeprazole
-tidineH2 receptor blockerFamotidine
-floxacinFluoroquinoloneCiprofloxacin
-cyclineTetracyclineDoxycycline
-mab / -ceptMonoclonal antibody / receptor fusion proteinInfliximab / etanercept
-tinibTyrosine kinase inhibitorImatinib
-triptan5-HT1B/1D agonist (migraine)Sumatriptan
-osinα1 blockerTamsulosin, prazosin

Monoclonal antibody names also encode the target and source: -ximab (chimeric), -zumab (humanized), -umab (human).

P-450 inducers and inhibitors

Most drug-interaction questions reduce to whether a new drug speeds up (induces) or slows down (inhibits) metabolism of an existing one.

Inducers (↓ other drug levels)RifampinCarbamazepine, phenytoin, phenobarbitalSt John's wortChronic alcohol useGriseofulvinEffect builds over days to weeksInhibitors (↑ other drug levels)Azole antifungalsClarithromycin, erythromycinRitonavir and other protease inhibitorsAmiodarone, diltiazem, verapamilGrapefruit juice, acute alcoholEffect within daysvs
P-450 interactions. Narrow-therapeutic-index drugs — warfarin, tacrolimus, cyclosporine, phenytoin, theophylline, and some statins — cause the most harm.

Toxidromes and antidotes

Recognizing a toxidrome identifies the drug class before any lab result.

ToxidromesAnticholinergicHot, dry, flushed,mydriasis, delirium,retentionCholinergicWet: salivation,sweating,bronchorrhea, miosisSympathomimeticHot, sweaty,mydriasis,tachycardia,agitationOpioidMiosis, bradypnea,coma
Toxidromes. Skin moisture separates anticholinergic (dry) from sympathomimetic (sweaty) toxicity, which look otherwise similar.
PoisonAntidote
AcetaminophenN-acetylcysteine
OpioidsNaloxone
BenzodiazepinesFlumazenil (rarely used — seizure risk)
OrganophosphatesAtropine + pralidoxime
AnticholinergicsPhysostigmine
TCAsSodium bicarbonate
β blockersGlucagon
DigoxinDigoxin immune Fab
Methanol, ethylene glycolFomepizole
IronDeferoxamine
LeadSuccimer, EDTA, dimercaprol
CyanideHydroxocobalamin
HeparinProtamine sulfate
WarfarinVitamin K + prothrombin complex concentrate
MethemoglobinemiaMethylene blue

Activated charcoal binds many ingested drugs but not alcohols, metals (iron, lithium), or caustics.

Toxicity by organ

Grouping drugs by the organ they damage turns a toxicity description into a short list of suspects.

Lungs (fibrosis)Bleomycin, amiodarone, methotrexate, busulfan,nitrofurantoinKidneyAminoglycosides, cisplatin, amphotericin B, NSAIDs,vancomycinEarAminoglycosides, loop diuretics, cisplatinHeartDoxorubicin, trastuzumab; QT: macrolides,antipsychoticsLiverAcetaminophen, isoniazid, valproate, statins,methotrexate
Organ toxicity. Each guide linked below explains the mechanism behind these patterns.
functions Worked example — use two patterns together

A patient on long-term amiodarone for atrial fibrillation develops a dry cough and bilateral reticular opacities. The cardiologist also notes his warfarin requirement has dropped by half. Which two patterns explain the findings?

  1. Pattern 1 — pulmonary fibrosis drugs: amiodarone is on the list.
  2. Pattern 2 — P-450 inhibitors: amiodarone inhibits CYP2C9, which metabolizes warfarin.
  3. Inhibition raises warfarin levels, so a lower dose achieves the same INR.

Answer. Amiodarone pulmonary toxicity plus CYP2C9 inhibition of warfarin metabolism. Check PFTs and imaging, and monitor INR closely.