Drug Classifications & Key Meds Study Guide

Q: How do I remember common drug suffixes and their classes?

Memorize these high-yield suffixes: -olol = beta blocker (metoprolol). -pril = ACE inhibitor (lisinopril). -sartan = ARB (losartan). -statin = cholesterol-lowering (atorvastatin). -dipine = calcium channel blocker (amlodipine). -azole = antifungal (fluconazole). -cycline = tetracycline antibiotic. -floxacin = fluoroquinolone. -cillin = penicillin. -prazole = PPI (omeprazole). -pam/-lam = benzodiazepine.

Q: What is the difference between an opioid agonist and antagonist?

Agonists activate opioid receptors → analgesia, sedation, respiratory depression, constipation (morphine, fentanyl, hydrocodone, oxycodone). Antagonists block them → reverse the effects (naloxone for overdose). Mixed agonist-antagonists (buprenorphine, butorphanol) have a ceiling effect for both analgesia and respiratory depression. Naloxone has a short half-life — may need repeat doses for long-acting opioids.

Q: What antibiotic classes have what coverage?

General rules: Penicillins (amoxicillin) and cephalosporins (cefazolin) — broad gram-positive, some gram-negative. Tetracyclines (doxycycline) — atypical organisms; avoid in pregnancy and children < 8 (tooth staining). Fluoroquinolones (ciprofloxacin) — broad spectrum; risk of tendon rupture. Macrolides (azithromycin) — atypical respiratory pathogens. Vancomycin — gram-positive including MRSA; risk of red-man syndrome (infuse slowly). Aminoglycosides (gentamicin) — gram-negative; risk of nephro- and ototoxicity.

Q: Why are some antibiotics taken on an empty stomach and others with food?

Some antibiotics are better absorbed on an empty stomach: penicillins, tetracyclines, levothyroxine (not an antibiotic but follows similar rule). Take 1 hour before or 2 hours after meals. Tetracyclines and fluoroquinolones bind to calcium, iron, and magnesium — avoid dairy products and antacids close to dosing. Some antibiotics need food to reduce GI upset: nitrofurantoin, metronidazole. Always check the specific drug.

Q: What is the difference between H1 and H2 blockers?

H1 blockers (antihistamines) block histamine in tissues — used for allergies, hives, motion sickness. First-generation (diphenhydramine/Benadryl) cross the blood-brain barrier — sedating. Second-generation (loratadine, cetirizine) are less sedating. H2 blockers block histamine receptors on stomach parietal cells — reduce acid production. Used for GERD, peptic ulcers. Names end in -tidine (famotidine, ranitidine). Often combined with PPIs for severe acid disease.

Q: What are the major types of insulin and their onsets?

Rapid-acting (lispro/Humalog, aspart/Novolog, glulisine): onset 15 min, peak 1–2 hr, duration 3–5 hr. Give right before meals. Short-acting (regular insulin): onset 30 min, peak 2–4 hr, duration 5–8 hr. The only insulin that can be given IV. Intermediate (NPH): onset 1–2 hr, peak 4–12 hr, duration 14–24 hr — cloudy, must be mixed. Long-acting (glargine/Lantus, detemir): onset 1–2 hr, no peak, duration 24 hr — clear, never mix. Mixing rule: clear before cloudy (Regular before NPH).

Q: What is the difference between Schedule II and Schedule IV controlled substances?

The Controlled Substances Act classifies drugs by abuse potential. Schedule I: no accepted medical use (heroin, LSD). Schedule II: high abuse potential, accepted medical use (oxycodone, morphine, fentanyl, methylphenidate). No refills allowed — new written or e-prescription required. Schedule III: moderate abuse (codeine combinations, ketamine). Schedule IV: low abuse (benzodiazepines, tramadol). Up to 5 refills in 6 months. Schedule V: lowest abuse (low-dose codeine cough syrup).

Q: What pregnancy categories should I know?

The old FDA categories (still tested): A = no risk in human studies (rare). B = animal studies show no risk OR animal risk not confirmed in humans (acetaminophen, penicillin). C = animal risk shown OR no studies — use only if benefit outweighs risk (many common drugs). D = evidence of human risk, but benefit may justify in serious conditions (phenytoin, lithium). X = contraindicated, risk outweighs any benefit (warfarin, isotretinoin, methotrexate, statins).

Q: What is the difference between absorption, distribution, metabolism, and excretion?

The four phases of pharmacokinetics ("ADME"): Absorption — how the drug enters the bloodstream (fastest IV, slowest oral). Distribution — how it moves to tissues (affected by protein binding, blood flow, lipid solubility). Metabolism — mostly liver (cytochrome P450 system); creates active or inactive metabolites. Excretion — mostly kidneys. Impaired liver or kidney function → adjust doses. Old age slows both.

Q: What is the difference between a therapeutic effect and a side effect?

Therapeutic effect = the intended drug action (lisinopril lowering BP). Side effect = an unintended but usually predictable response (lisinopril dry cough). Adverse effect = a more severe unintended response (lisinopril angioedema). Allergic reaction = immune-mediated response (rash, hives, anaphylaxis). Toxicity = effects from excessive drug levels (digoxin toxicity). Document and report severity appropriately.

Antidotes — Know These Cold

If you only memorize one table in pharmacology, make it this one.

Opioidsmorphine, fentanyl, hydrocodone: Naloxone (Narcan) — Reverses respiratory depression. Short half-life — may need repeat doses. Can precipitate withdrawal.
Benzodiazepineslorazepam, diazepam, midazolam: Flumazenil (Romazicon) — Reverses sedation. Risk of seizures — use cautiously in chronic benzo users.
Heparin: Protamine sulfate — Binds heparin and neutralizes it. Give slowly IV — can cause hypotension and bradycardia.
Warfarin (Coumadin): Vitamin K (phytonadione) — Takes 6–24 hours for full effect. For emergent bleeding: fresh frozen plasma (FFP) for immediate reversal.
Digoxin: Digibind (digoxin immune Fab) — For severe toxicity: bradycardia, lethal arrhythmias, K⁺ >5.0 with dig toxicity.
Acetaminophen (Tylenol): N-acetylcysteine (Mucomyst/Acetadote) — Must give within 8–10 hours of ingestion for best outcome. Smells/tastes bad — mix with cola or juice.
Magnesium sulfate: Calcium gluconate — Keep at bedside during mag sulfate infusion. Toxicity: absent reflexes, respiratory depression, cardiac arrest.
Methotrexate: Leucovorin (folinic acid) — "Leucovorin rescue" — protects normal cells from methotrexate toxicity.
Organophosphatespesticides, nerve agents: Atropine — Blocks excess acetylcholine. Also give pralidoxime (2-PAM). Remember: SLUDGE symptoms (salivation, lacrimation, urination, defecation, GI distress, emesis).
Iron: Deferoxamine (Desferal) — Iron chelator — binds iron for excretion. Turns urine red/orange.
Lead: Succimer (Chemet) / CaEDTA — Chelation therapy for lead poisoning. Most common in children (lead paint).
TCAsamitriptyline, nortriptyline: Sodium bicarbonate (NaHCO₃) — Treats the cardiac toxicity (widened QRS, arrhythmias) of tricyclic overdose.
Methanol / Ethylene glycol: Fomepizole — Inhibits alcohol dehydrogenase, preventing formation of toxic metabolites.
Cyanidesmoke inhalation: Hydroxocobalamin (Cyanokit) — Binds cyanide for renal excretion. Turns skin/urine red.
tPA (alteplase): Aminocaproic acid (Amicar) — Inhibits fibrinolysis — stops bleeding caused by thrombolytics.

Exam Tip

The top 5 antidotes you'll see most often: Naloxone (opioids), Flumazenil (benzos), Protamine (heparin), Vitamin K (warfarin), and N-acetylcysteine (acetaminophen). If a question describes respiratory depression + pinpoint pupils → think opioid overdose → naloxone.

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Therapeutic Drug Levels

Ranges vary by lab, facility, and textbook — for exams, use the range given in the question. See the full NCLEX-PN lab-value reference & sources →

Narrow therapeutic index drugs — a small dose change can mean the difference between therapeutic and toxic.

Digoxin: 0.5–2.0 ng/mL · N/V, anorexia, bradycardia, yellow-green visual halos, dysrhythmias. Hypokalemia ↑ toxicity risk.
Lithium: 0.6–1.2 mEq/L (maintenance) · Fine tremor → coarse tremor → confusion → seizures → coma. Dehydration and low Na⁺ ↑ levels. Draw level 8–12 hrs post-dose.
Phenytoin (Dilantin): 10–20 mcg/mL · Nystagmus, ataxia, slurred speech, confusion. Gingival hyperplasia with chronic use.
Valproic acid (Depakote): 50–100 mcg/mL · Hepatotoxicity, pancreatitis, thrombocytopenia. Monitor LFTs.
Carbamazepine (Tegretol): 4–12 mcg/mL · Diplopia, dizziness, ataxia. Monitor CBC (aplastic anemia risk).
Vancomycin: Trough: 10–20 mcg/mL · Ototoxicity (hearing loss), nephrotoxicity (monitor BUN/Cr). Red Man Syndrome if infused too fast.
Gentamicin/Tobramycin: Trough: <2 mcg/mL · Ototoxicity (tinnitus, hearing loss), nephrotoxicity. Monitor peaks & troughs, BUN/Cr.
Theophylline: 10–20 mcg/mL · Tachycardia, N/V, seizures, restlessness. Caffeine-like effects. Avoid caffeine.
INR (warfarin): 2.0–3.0 standard · 2.5–3.5 mechanical valve · Bleeding: gums, bruising, blood in stool/urine. Antidote: vitamin K.
aPTT (heparin): 1.5–2.5× normal (≈46–70 sec) · Bleeding. Antidote: protamine sulfate. Watch for HIT (platelets drop).

Memory Trick for Lithium

Lithium level = "1.2 is the limit" for maintenance. Draw levels 8–12 hours after last dose. Toxicity is increased by dehydration, low sodium, and NSAIDs. Teach patient to maintain consistent salt and fluid intake.

Antibiotics

Know the class, the suffix, the key side effects, and the patient teaching.

Penicillins-cillin · amoxicillin, ampicillin: Ask about allergy FIRST (cross-reactivity with cephalosporins). Anaphylaxis risk. Take full course.
Cephalosporinscef-, ceph- · cephalexin (Keflex), ceftriaxone: Cross-allergy with penicillin (5–10%). Monitor for allergic reactions. Avoid alcohol (disulfiram-like reaction with some).
Fluoroquinolones-floxacin · ciprofloxacin, levofloxacin: Risk of tendon rupture (especially Achilles) — stop and report tendon pain. Avoid in children. Photosensitivity. Take 2 hrs before/after antacids.
Aminoglycosides-mycin, -micin · gentamicin, tobramycin, amikacin: Monitor peak & trough levels. Ototoxicity (hearing loss, tinnitus) + nephrotoxicity (monitor BUN/Cr). Given IV/IM only.
Macrolides-thromycin · azithromycin (Z-pack), erythromycin: GI upset common. Monitor QT prolongation. Erythromycin: many drug interactions.
Tetracyclines-cycline · doxycycline, tetracycline: Avoid dairy/antacids (block absorption). Photosensitivity. Do NOT use in pregnancy or children <8 (tooth discoloration).
Sulfonamidessulfa- · sulfamethoxazole/TMP (Bactrim): Increase fluid intake (prevent crystalluria). Photosensitivity. Allergic reactions common. Avoid in late pregnancy.
Vancomycinstandalone — no class suffix: IV for MRSA. Infuse slowly (≥60 min) — Red Man Syndrome if too fast (flushing, rash → slow rate, give antihistamine). Monitor trough levels. Ototoxic + nephrotoxic.
Metronidazole (Flagyl)standalone: Used for C. diff, anaerobic infections, H. pylori. ABSOLUTELY NO ALCOHOL (disulfiram-like reaction — severe N/V, flushing, headache). Metallic taste.

TB Drugs — RIPE Therapy

Rifampin — turns body fluids orange/red (harmless), decreases oral contraceptive effectiveness, monitor LFTs
Isoniazid (INH) — hepatotoxic; give vitamin B6 (pyridoxine) to prevent peripheral neuropathy; avoid alcohol
Pyrazinamide — hepatotoxic, raises uric acid (gout risk)
Ethambutol — monitor vision (optic neuritis — report blurred vision or color changes)

Antibiotic Golden Rules

1) Always ask about allergies BEFORE giving. 2) Obtain culture BEFORE first dose (but don't delay treatment). 3) Take the FULL course (stopping early promotes resistance). 4) Monitor for superinfection (oral thrush, vaginal yeast — caused by killing normal flora).

Antivirals

Antivirals don't cure — they suppress viral replication.

Acyclovir (Zovirax)-cyclovir: Herpes (HSV), varicella, shingles. Increase fluids (nephrotoxicity risk). Most effective if started within 72 hrs of symptom onset.
Oseltamivir (Tamiflu)-amivir: Influenza A & B. Must start within 48 hrs of symptom onset. Reduces duration by 1–2 days.
Antiretrovirals (HIV)various: -vir, -avir, -udine: HAART/ART therapy (multiple drug combo). Monitor viral load & CD4 count. Never miss doses (resistance). Many drug interactions.
Ribavirin-virin: Hepatitis C (with other agents), RSV in children. TERATOGENIC — avoid pregnancy (both partners). Handle with gloves.

Key Principle

Antivirals SUPPRESS viral replication — they do not CURE the virus. The patient is still infectious. Teach: medication compliance is critical (especially HIV — missing doses causes drug resistance).

Antifungals

Suffix: -azole (for most) and amphotericin B (the "big gun").

Fluconazole (Diflucan)-azole (azoles): Oral/systemic candidiasis (yeast). Monitor liver function (hepatotoxic). Many drug interactions (CYP450 inhibitor).
Nystatinstandalone: Oral thrush — "swish and swallow" (or swish and spit). Topical for skin fungal infections. Minimal systemic absorption.
Amphotericin Bstandalone — "Ampho-terrible": Severe systemic fungal infections. HIGHLY nephrotoxic — monitor BUN/Cr, K⁺, Mg²⁺. Causes fever, chills, rigors during infusion. Premedicate with acetaminophen, diphenhydramine, meperidine. Infuse slowly.
Clotrimazole-azole: Topical: vaginal yeast infections, athlete's foot, jock itch. OTC available.

Exam Tip

Amphotericin B is called "Ampho-terrible" because of its severe side effects — primarily nephrotoxicity. If a question mentions a systemic antifungal with renal concerns → think amphotericin B. Always monitor kidney function and electrolytes (K⁺ and Mg²⁺ depletion).

Anxiolytics & Sedatives

Suffixes: -azepam, -olam (benzodiazepines). Know the risks and the antidote.

Benzodiazepines (the -azepam / -olam drugs)

Lorazepam (Ativan): Anxiety, status epilepticus (first-line), pre-op sedation
Diazepam (Valium): Anxiety, seizures, muscle spasms, alcohol withdrawal
Midazolam (Versed): Conscious sedation, pre-procedure
Alprazolam (Xanax): Anxiety, panic disorder

Key Nursing Considerations

Antidote: Flumazenil (Romazicon)
CNS depression — monitor respiratory rate, sedation level. Risk increases when combined with opioids or alcohol.
Do NOT stop abruptly — taper gradually (withdrawal can cause seizures)
Fall risk — sedation, dizziness, impaired coordination (especially in elderly)
Avoid in pregnancy (teratogenic)
Short-term use only — risk of physical and psychological dependence
Avoid alcohol and other CNS depressants

Non-Benzodiazepine Anxiolytic

Buspirone (BuSpar): Used for generalized anxiety disorder. Takes 2–4 weeks for full effect (not for PRN use). Does NOT cause sedation or dependence. Does NOT potentiate CNS depressants. Cannot be used for acute anxiety or panic.

Benzo + Opioid = Respiratory Arrest

Combining benzodiazepines with opioids dramatically increases the risk of fatal respiratory depression. This is one of the most dangerous drug interactions. If a patient is on both, monitor respiratory rate very closely. RR <12 → hold and notify provider.

Antidepressants

SSRIs are first-line. Know the black box warning and serotonin syndrome.

SSRIs-pram, -ine · fluoxetine (Prozac), sertraline (Zoloft), escitalopram (Lexapro), paroxetine (Paxil): First-line for depression/anxiety. Takes 2–6 weeks for full effect. Fewest side effects. Sexual dysfunction common. Do NOT combine with MAOIs.
SNRIs-faxine · venlafaxine (Effexor), duloxetine (Cymbalta): Depression + neuropathic pain + fibromyalgia. Monitor BP (can increase). Similar to SSRIs but dual-action.
TCAs-triptyline, -pramine · amitriptyline, nortriptyline, imipramine: Older class. Anticholinergic effects (dry mouth, urinary retention, constipation, blurred vision). Cardiotoxic in overdose (arrhythmias). Avoid in elderly.
MAOIs-ine (various) · phenelzine (Nardil), tranylcypromine (Parnate): LAST resort — dangerous food and drug interactions. Avoid tyramine-rich foods (aged cheese, wine, soy sauce, smoked meats, beer) → hypertensive crisis. NEVER combine with SSRIs/SNRIs (serotonin syndrome).

Black Box Warning — ALL Antidepressants

Increased risk of suicidal ideation in children, adolescents, and young adults (under 25), especially during the first few weeks of treatment. Monitor closely for mood changes, agitation, and suicidal thoughts. Educate family to watch for behavioral changes.

Serotonin Syndrome

A life-threatening condition caused by too much serotonin (usually from combining serotonergic drugs — SSRIs + MAOIs, SSRIs + triptans, etc.). Signs: agitation, confusion, rapid HR, hypertension, hyperthermia, muscle rigidity, clonus (involuntary muscle contractions), diaphoresis, diarrhea. Treatment: stop the offending drug, supportive care, cyproheptadine (serotonin antagonist).

Antipsychotics

First-gen vs second-gen — and the critical side effects EPS and NMS.

First-Generation (Typical)-azine: chlorpromazine, fluphenazine · haloperidol (Haldol): Main concern: HIGH risk of EPS and tardive dyskinesia. Used for schizophrenia (positive symptoms: hallucinations, delusions).
Second-Generation (Atypical)-pine, -done: olanzapine, risperidone, quetiapine, clozapine, aripiprazole: Main concern: Metabolic syndrome — weight gain, hyperglycemia, hyperlipidemia. Used for schizophrenia (positive AND negative symptoms), bipolar, treatment-resistant cases.

Extrapyramidal Symptoms (EPS) — Know All 4 Types

Acute dystoniahours to days: Severe muscle spasms (neck, eyes, tongue, jaw — torticollis, oculogyric crisis). Treatment: Benztropine (Cogentin) or diphenhydramine (Benadryl) IM.
Akathisiadays to weeks: Restlessness, inability to sit still, constant movement. Treatment: reduce dose, propranolol, or benzodiazepine.
Pseudoparkinsonismweeks to months: Tremor, rigidity, shuffling gait, mask-like face (mimics Parkinson's). Treatment: Benztropine (Cogentin) or amantadine.
Tardive dyskinesiamonths to years: Involuntary movements of face, tongue, jaw (lip smacking, tongue protrusion). Often IRREVERSIBLE. Prevention is key — monitor early. May need to stop drug.

Neuroleptic Malignant Syndrome (NMS) — MEDICAL EMERGENCY

A rare but life-threatening reaction to antipsychotics. Signs: HIGH fever (>104°F), severe muscle rigidity ("lead pipe"), altered mental status, autonomic instability (labile BP, tachycardia, diaphoresis), elevated CK. Treatment: STOP the drug, dantrolene, bromocriptine, cooling measures, aggressive IV hydration. Mortality is high without treatment.

Clozapine (Clozaril) — Special Monitoring

The most effective antipsychotic for treatment-resistant schizophrenia. BUT: requires regular CBC monitoring because of the risk of AGRANULOCYTOSIS (dangerously low WBCs → fatal infection). Monitor the ANC, not the WBC: clozapine generally is not started if baseline ANC is below 1,500/mm3. During therapy, ANC 1,000–1,499 usually means continue with increased monitoring; interrupt for ANC 500–999 and resume when ANC is ≥1,000; discontinue for ANC below 500. The FDA has removed the clozapine REMS requirement. Weekly blood draws required initially.

Cardiac Drugs

Know the suffix, know the assessment before you give it.

Beta-blockers-olol · metoprolol, atenolol, propranolol, carvedilol: ↓HR, ↓BP, ↓cardiac workload. Hold if HR <60 or SBP <90. Never stop abruptly (rebound HTN/MI). Mask hypoglycemia in diabetics. In asthma, avoid the nonselective agents (propranolol, carvedilol) — they block beta-2 and can trigger bronchospasm; the cardioselective ones (metoprolol, atenolol) are used with caution.
ACE Inhibitors-pril · lisinopril, enalapril, captopril, ramipril: First-line for HF & HTN. Dry cough (switch to ARB). Angioedema → STOP immediately. Monitor K⁺ (hyperkalemia). Avoid in pregnancy.
ARBs-sartan · losartan, valsartan, irbesartan: Alternative when ACE causes cough. Same benefits, no cough. Monitor K⁺. Avoid in pregnancy.
CCBs-dipine (dihydropyridines) · amlodipine, nifedipine · also: diltiazem, verapamil: Vasodilation → ↓BP. -dipine drugs mainly affect vessels. Diltiazem/verapamil also ↓HR. SE: peripheral edema, constipation, flushing.
Statins-statin · atorvastatin (Lipitor), simvastatin, rosuvastatin: ↓LDL cholesterol. Take at bedtime (cholesterol synthesis peaks at night). Monitor liver function. Report muscle pain (rhabdomyolysis risk → check CK). Avoid grapefruit (some statins).
Digoxinstandalone: ↑Contractility, ↓HR. Apical pulse × 1 full minute before giving — hold if <60. Therapeutic: 0.5–2.0 ng/mL. Low K⁺ ↑ toxicity. Toxicity: N/V, halos, bradycardia. Antidote: Digibind.
Nitratesnitro- · nitroglycerin: Vasodilator for angina. SL: if no relief 5 min after 1st dose → call 911 (may take up to 3 total, 5 min apart). Hold if SBP <90. Headache = expected. NO PDE-5 inhibitors (Viagra). Store in dark glass, replace q6mo.
Anticoagulantsheparin → aPTT · warfarin → INR: Heparin antidote: protamine. Warfarin antidote: Vit K. INR goal: 2.0–3.0. Avoid leafy greens with warfarin. Monitor for bleeding (gums, bruising, blood in stool/urine).

→ Go deeper with the full Cardiovascular Medications guide.

Respiratory Drugs

Rescue vs maintenance — and always rinse after inhaled steroids.

SABAs (rescue)-terol (short-acting) · albuterol (ProAir, Ventolin): Rescue inhaler — use FIRST during asthma attack. SE: tachycardia, tremors. If using >2x/week → poorly controlled asthma.
LABAs (maintenance)-terol (long-acting) · salmeterol (Serevent), formoterol: Maintenance only — NEVER for acute attacks. Always used WITH an inhaled corticosteroid.
Inhaled corticosteroids-sone, -ide · fluticasone (Flovent), budesonide: Maintenance — reduces inflammation. RINSE MOUTH after use (prevents oral thrush). Not for acute attacks.
Anticholinergics-tropium · ipratropium (Atrovent), tiotropium (Spiriva): Bronchodilator for COPD. Slower onset than albuterol. Often combined with albuterol (DuoNeb).
Leukotriene modifiers-lukast · montelukast (Singulair): Oral maintenance for asthma. Take at bedtime. Not for acute attacks. Monitor for behavioral changes (rare).

Inhaler Order

If a patient uses both a bronchodilator and an inhaled steroid: use the bronchodilator FIRST (opens airways), wait 1–2 minutes, then use the steroid (penetrates deeper). Always use a spacer with MDIs.

→ Go deeper with the full Respiratory Medications guide.

Endocrine Drugs

The most tested endocrine drugs: insulin, metformin, levothyroxine, and steroids.

Metformin (Glucophage)Biguanide — Type 2 DM (first-line): Does NOT cause hypoglycemia alone. Hold before contrast dye (48 hrs). Rare: lactic acidosis (report muscle pain). Avoid alcohol.
Glipizide/GlyburideSulfonylureas — Type 2 DM: Suffix: -ide. Stimulates pancreas to release insulin. CAN cause hypoglycemia. Take 30 min before meals.
InsulinType 1 (always) & Type 2 DM: Rapid (lispro): 15 min onset. Regular: 30 min. NPH: 1–2 hrs. Lantus: no peak, 24 hrs. Only Regular goes IV. Clear before cloudy. Never mix Lantus.
Levothyroxine (Synthroid)Thyroid replacement: Hypothyroidism — lifelong. Take AM, empty stomach, 30–60 min before food. Monitor HR (tachycardia = too much). Consistent dosing.
Methimazole / PTUAnti-thyroid: Hyperthyroidism. Blocks thyroid hormone production. Monitor WBCs (agranulocytosis — report sore throat/fever). PTU preferred in 1st trimester pregnancy.
PrednisoneCorticosteroid: Anti-inflammatory, immunosuppressant. Take with food. Taper slowly — never stop abruptly. SE: hyperglycemia, immunosuppression, osteoporosis, weight gain, mood changes, adrenal suppression.

Pain & Anti-Inflammatory Drugs

Opioids, NSAIDs, and the ceiling dose concept.

Opioidsmorphine, hydrocodone, oxycodone, fentanyl, hydromorphone, codeine, tramadol: Antidote: naloxone. Hold if RR <12. SE: constipation (always give bowel regimen), sedation, respiratory depression, urinary retention, N/V, itching. Constipation does NOT develop tolerance. High abuse potential (Schedule II).
NSAIDsibuprofen, naproxen, ketorolac (Toradol), celecoxib (Celebrex): Take with food (GI irritation/bleeding). Avoid in renal disease. Monitor for bleeding. Avoid pre-op. Celecoxib = COX-2 selective (less GI risk but CV risk). Ketorolac: max 5 days.
Acetaminophen (Tylenol)standalone: No anti-inflammatory effect. Max 3–4 g/day. Hepatotoxic in excess. Antidote: N-acetylcysteine. Avoid with alcohol/liver disease. Check all combo drugs (many contain acetaminophen).
Gabapentin/Pregabalingabapentin (Neurontin), pregabalin (Lyrica): Neuropathic pain, fibromyalgia, seizures. SE: drowsiness, dizziness. Do NOT stop abruptly (seizure risk). Not a controlled substance (gabapentin — pregabalin is Schedule V).

Opioid Safety Check

Before giving ANY opioid: check respiratory rate. If RR <12 → HOLD and notify provider. Keep naloxone at bedside for high-risk patients. Constipation is the ONE opioid side effect that does NOT develop tolerance — always provide a bowel regimen.

→ Go deeper with the full Pain & Anesthesia Medications guide.

Master Suffix Table

Your cheat code for identifying drug classes on sight.

-olol: Beta-blocker · metoprolol, atenolol, propranolol
-pril: ACE inhibitor · lisinopril, enalapril, captopril
-sartan: ARB · losartan, valsartan, irbesartan
-dipine: Calcium channel blocker · amlodipine, nifedipine
-statin: HMG-CoA reductase inhibitor (cholesterol) · atorvastatin, simvastatin
-azepam / -olam: Benzodiazepine · lorazepam, diazepam, alprazolam
-azine: First-gen antipsychotic (phenothiazine) · chlorpromazine, fluphenazine
-pine / -done: Second-gen antipsychotic (atypical) · olanzapine, risperidone, quetiapine
-pram / -ine: SSRI antidepressant · escitalopram, fluoxetine, sertraline
-faxine: SNRI antidepressant · venlafaxine, duloxetine
-triptyline: TCA antidepressant · amitriptyline, nortriptyline
-cillin: Penicillin antibiotic · amoxicillin, ampicillin
-floxacin: Fluoroquinolone antibiotic · ciprofloxacin, levofloxacin
-mycin / -micin: Aminoglycoside antibiotic · gentamicin, tobramycin
-thromycin: Macrolide antibiotic · azithromycin, erythromycin
-cycline: Tetracycline antibiotic · doxycycline, tetracycline
-azole: Antifungal · fluconazole, clotrimazole
-cyclovir: Antiviral (herpes) · acyclovir, valacyclovir
-terol: Beta-2 agonist (bronchodilator) · albuterol, salmeterol
-sone / -ide: Corticosteroid (inhaled) · fluticasone, budesonide, prednisone
-tropium: Anticholinergic bronchodilator · ipratropium, tiotropium
-lukast: Leukotriene modifier · montelukast
-dronate: Bisphosphonate (osteoporosis) · alendronate, risedronate
-prazole: Proton pump inhibitor · omeprazole, pantoprazole
-tidine: H2 blocker · famotidine, ranitidine
-setron: Antiemetic (5-HT3 antagonist) · ondansetron

? A drug ends in "-sartan." What class is it, and what side effect does it NOT cause that the similar class does?

"-sartan" = ARB (angiotensin receptor blocker). ARBs work like ACE inhibitors but do NOT cause the persistent dry cough associated with ACE inhibitors. Both classes can cause hyperkalemia and are contraindicated in pregnancy.

Frequently Asked Questions

Common student questions on this topic.

How do I remember common drug suffixes and their classes?

Memorize these high-yield suffixes: -olol = beta blocker (metoprolol). -pril = ACE inhibitor (lisinopril). -sartan = ARB (losartan). -statin = cholesterol-lowering (atorvastatin). -dipine = calcium channel blocker (amlodipine). -azole = antifungal (fluconazole). -cycline = tetracycline antibiotic. -floxacin = fluoroquinolone. -cillin = penicillin. -prazole = PPI (omeprazole). -pam/-lam = benzodiazepine.

What is the difference between an opioid agonist and antagonist?

Agonists activate opioid receptors → analgesia, sedation, respiratory depression, constipation (morphine, fentanyl, hydrocodone, oxycodone). Antagonists block them → reverse the effects (naloxone for overdose). Mixed agonist-antagonists (buprenorphine, butorphanol) have a ceiling effect for both analgesia and respiratory depression. Naloxone has a short half-life — may need repeat doses for long-acting opioids.

What antibiotic classes have what coverage?

General rules: Penicillins (amoxicillin) and cephalosporins (cefazolin) — broad gram-positive, some gram-negative. Tetracyclines (doxycycline) — atypical organisms; avoid in pregnancy and children < 8 (tooth staining). Fluoroquinolones (ciprofloxacin) — broad spectrum; risk of tendon rupture. Macrolides (azithromycin) — atypical respiratory pathogens. Vancomycin — gram-positive including MRSA; risk of red-man syndrome (infuse slowly). Aminoglycosides (gentamicin) — gram-negative; risk of nephro- and ototoxicity.

Why are some antibiotics taken on an empty stomach and others with food?

Some antibiotics are better absorbed on an empty stomach: penicillins, tetracyclines, levothyroxine (not an antibiotic but follows similar rule). Take 1 hour before or 2 hours after meals. Tetracyclines and fluoroquinolones bind to calcium, iron, and magnesium — avoid dairy products and antacids close to dosing. Some antibiotics need food to reduce GI upset: nitrofurantoin, metronidazole. Always check the specific drug.

What is the difference between H1 and H2 blockers?

H1 blockers (antihistamines) block histamine in tissues — used for allergies, hives, motion sickness. First-generation (diphenhydramine/Benadryl) cross the blood-brain barrier — sedating. Second-generation (loratadine, cetirizine) are less sedating. H2 blockers block histamine receptors on stomach parietal cells — reduce acid production. Used for GERD, peptic ulcers. Names end in -tidine (famotidine, ranitidine). Often combined with PPIs for severe acid disease.

What are the major types of insulin and their onsets?

Rapid-acting (lispro/Humalog, aspart/Novolog, glulisine): onset 15 min, peak 1–2 hr, duration 3–5 hr. Give right before meals. Short-acting (regular insulin): onset 30 min, peak 2–4 hr, duration 5–8 hr. The only insulin that can be given IV. Intermediate (NPH): onset 1–2 hr, peak 4–12 hr, duration 14–24 hr — cloudy, must be mixed. Long-acting (glargine/Lantus, detemir): onset 1–2 hr, no peak, duration 24 hr — clear, never mix. Mixing rule: clear before cloudy (Regular before NPH).

What is the difference between Schedule II and Schedule IV controlled substances?

The Controlled Substances Act classifies drugs by abuse potential. Schedule I: no accepted medical use (heroin, LSD). Schedule II: high abuse potential, accepted medical use (oxycodone, morphine, fentanyl, methylphenidate). No refills allowed — new written or e-prescription required. Schedule III: moderate abuse (codeine combinations, ketamine). Schedule IV: low abuse (benzodiazepines, tramadol). Up to 5 refills in 6 months. Schedule V: lowest abuse (low-dose codeine cough syrup).

What pregnancy categories should I know?

The old FDA categories (still tested): A = no risk in human studies (rare). B = animal studies show no risk OR animal risk not confirmed in humans (acetaminophen, penicillin). C = animal risk shown OR no studies — use only if benefit outweighs risk (many common drugs). D = evidence of human risk, but benefit may justify in serious conditions (phenytoin, lithium). X = contraindicated, risk outweighs any benefit (warfarin, isotretinoin, methotrexate, statins).

What is the difference between absorption, distribution, metabolism, and excretion?

The four phases of pharmacokinetics ("ADME"): Absorption — how the drug enters the bloodstream (fastest IV, slowest oral). Distribution — how it moves to tissues (affected by protein binding, blood flow, lipid solubility). Metabolism — mostly liver (cytochrome P450 system); creates active or inactive metabolites. Excretion — mostly kidneys. Impaired liver or kidney function → adjust doses. Old age slows both.

What is the difference between a therapeutic effect and a side effect?

Therapeutic effect = the intended drug action (lisinopril lowering BP). Side effect = an unintended but usually predictable response (lisinopril dry cough). Adverse effect = a more severe unintended response (lisinopril angioedema). Allergic reaction = immune-mediated response (rash, hives, anaphylaxis). Toxicity = effects from excessive drug levels (digoxin toxicity). Document and report severity appropriately.

What is the difference between a generic and a brand name drug?

The generic name is the official chemical name (acetaminophen, metoprolol) — typically lowercase. The brand name is the trademarked name created by the manufacturer (Tylenol, Lopressor) — capitalized. Generic drugs are bioequivalent to brand drugs and typically much cheaper. Some narrow-therapeutic-range drugs (warfarin, levothyroxine, digoxin) should not be switched between brand and generic without monitoring, due to small variations in absorption.

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Drug Classifications & Key Medications

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Antidotes — Know These Cold

Therapeutic Drug Levels

Antibiotics

TB Drugs — RIPE Therapy

Antivirals

Antifungals

Anxiolytics & Sedatives

Benzodiazepines (the -azepam / -olam drugs)

Key Nursing Considerations

Non-Benzodiazepine Anxiolytic

Antidepressants

Antipsychotics

Extrapyramidal Symptoms (EPS) — Know All 4 Types

Cardiac Drugs

Respiratory Drugs

Endocrine Drugs

Pain & Anti-Inflammatory Drugs

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Frequently Asked Questions

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Drug Classifications & Key Medications Cheatsheet

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Drug Classifications & Key Medications

Want to see what you already know?

In This Guide

Antidotes — Know These Cold

Therapeutic Drug Levels

Antibiotics

TB Drugs — RIPE Therapy

Antivirals

Antifungals

Anxiolytics & Sedatives

Benzodiazepines (the -azepam / -olam drugs)

Key Nursing Considerations

Non-Benzodiazepine Anxiolytic

Antidepressants

Antipsychotics

Extrapyramidal Symptoms (EPS) — Know All 4 Types

Cardiac Drugs

Respiratory Drugs

Endocrine Drugs

Pain & Anti-Inflammatory Drugs

Master Suffix Table

Frequently Asked Questions

Quick-Reference Cheatsheet

Drug Classifications & Key Medications Cheatsheet

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Cardiovascular Medications

OB/Maternity Medications

Pain & Anesthesia Medications

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