NCLEX Pharmacology Made Easy: Drug Classes, Suffixes, and Must-Know Medications

Pharmacology is one of the most challenging subjects for NCLEX candidates, yet it’s impossible to avoid—medication questions appear throughout the exam across all content areas. The good news? You don’t need to memorize every drug. By understanding drug classes, learning suffix patterns, and focusing on high-yield medications, you can confidently tackle any pharmacology question on the NCLEX.

The Smart Approach to NCLEX Pharmacology

Instead of memorizing hundreds of individual drugs, focus on:

• Drug class characteristics: How drugs in each class work
• Suffix patterns: What drug name endings tell you
• Prototype drugs: The “model” drug for each class
• Nursing implications: What nurses need to monitor and teach
• Safety priorities: What could cause harm

Essential Drug Suffixes You Must Know

Drug names follow patterns. Learn these suffixes and you’ll recognize drug classes instantly:

Cardiovascular Medications

Anti-Infective Medications

CNS Medications

Other Common Suffixes

High-Priority Drug Classes for NCLEX

1. Anticoagulants

Drugs: Heparin, Warfarin (Coumadin), Enoxaparin (Lovenox), Rivaroxaban (Xarelto)

Key Points:

• Heparin: Monitor PTT, antidote is protamine sulfate
• Warfarin: Monitor PT/INR (goal usually 2-3), antidote is Vitamin K
• Lovenox: No routine monitoring, given subQ
• All: Watch for bleeding signs, teach to avoid injury

NCLEX Favorites:

• Which lab to monitor?
• Signs of toxicity/bleeding
• Patient teaching (avoid vitamin K-rich foods with warfarin)
• Antidotes

2. Cardiac Glycosides (Digoxin)

Key Points:

• Hold if HR less than 60 (adult) or less than 100 (infant)
• Therapeutic level: 0.5-2.0 ng/mL
• Toxicity signs: Visual disturbances (halos), bradycardia, nausea
• Low potassium increases toxicity risk
• Antidote: Digoxin immune fab (Digibind)

3. Insulin

Types and Onset:

• Rapid-acting: Lispro, Aspart (onset 15 min) – clear
• Short-acting: Regular (onset 30-60 min) – clear
• Intermediate: NPH (onset 2-4 hours) – cloudy
• Long-acting: Glargine, Detemir (24 hours) – clear, do NOT mix

Key Points:

• Only Regular insulin can be given IV
• When mixing: Clear before cloudy (Regular before NPH)
• Rotate injection sites
• Hypoglycemia signs and treatment

4. Opioid Analgesics

Drugs: Morphine, Hydromorphone (Dilaudid), Fentanyl, Oxycodone

Key Points:

• Monitor respiratory rate (hold if less than 12)
• Common side effects: Constipation, sedation, nausea
• Antidote: Naloxone (Narcan)
• Use pain scale for assessment

5. Antidepressants

SSRIs: Fluoxetine (Prozac), Sertraline (Zoloft)

• Takes 2-4 weeks for therapeutic effect
• Watch for serotonin syndrome
• Don’t stop abruptly

MAOIs: Phenelzine, Tranylcypromine

• Avoid tyramine-rich foods (aged cheese, wine, cured meats)
• Hypertensive crisis risk

6. Antipsychotics

Typical (First-gen): Haloperidol (Haldol)

• Risk of EPS (extrapyramidal symptoms)
• Tardive dyskinesia with long-term use

Atypical (Second-gen): Risperidone, Olanzapine

• Lower EPS risk, but metabolic effects
• Monitor weight, blood sugar

Medication Safety: Never Events

Know these critical safety points:

• High-alert medications: Insulin, opioids, anticoagulants, chemotherapy
• Look-alike/sound-alike drugs: Double-check orders
• The 6 Rights: Right patient, drug, dose, route, time, documentation
• Drug allergies: Always verify before administration

Dosage Calculations

You must be able to calculate:

Basic Formula

Dose Desired ÷ Dose on Hand × Quantity = Amount to Give

IV Drip Rates

(Volume × Drop Factor) ÷ Time in Minutes = Drops per Minute

Weight-Based Dosing

Patient Weight (kg) × Dose per kg = Total Dose

Know that 1 kg = 2.2 lbs

Study Strategies for Pharmacology

1. Learn drug classes, not individual drugs: If you know how ACE inhibitors work, you can answer questions about any -pril drug
2. Use flashcards: Great for suffixes and quick facts
3. Practice calculation problems daily: Accuracy is essential
4. Focus on nursing implications: The NCLEX cares about what nurses DO, not just what drugs are
5. Know your antidotes: Warfarin→Vitamin K, Heparin→Protamine, Opioids→Narcan, Digoxin→Digibind, Benzodiazepines→Flumazenil

Practice Questions Mindset

When you encounter a drug you don’t recognize:

1. Look at the suffix – can you identify the drug class?
2. Apply your knowledge of that drug class
3. Focus on safety and nursing implications
4. Use the process of elimination

You don’t need to know every drug—but you DO need to know the principles that keep patients safe.