NCLEX pharmacology cheat sheet: endings, checks, antidotes and levels

A sourced pharmacology cheat sheet for nursing exams: drug name endings, what to check before a dose, adverse effects, antidotes and therapeutic levels.

Key points

The ending of a generic name points to its class.
Digoxin and beta blockers: check the pulse. Below 60, hold and call.
Naloxone reverses opioids. Protamine reverses heparin. Vitamin K reverses warfarin.
Do not stop corticosteroids, clonidine or phenytoin abruptly.

This sheet covers the pharmacology facts that licensing-exam questions return to: what a drug's name tells you, what to check before a dose, which adverse effect to watch for, and which antidote reverses it. Every row comes from an open nursing or medical reference, listed at the end.

Sources checked 6 October 2026.

Drug name endings and their classes

Generic names share endings, called stems, that mark the drug's class. The World Health Organization assigns them. Learn the ending and you can place a drug you have never seen.

Ending	Class	Example
-pril	ACE inhibitors	captopril
-sartan	Angiotensin II receptor blockers	losartan
-olol	Beta blockers	metoprolol
-dipine	Calcium channel blockers	amlodipine
-vastatin	Statins (HMG-CoA reductase inhibitors)	atorvastatin
-semide	Loop diuretics of the furosemide type	furosemide
-parin	Heparins, including low molecular weight heparins	enoxaparin
-xaban	Factor Xa inhibitors	rivaroxaban
-prazole	Proton pump inhibitors	omeprazole
-tidine	H2 receptor antagonists	famotidine
-setron	Serotonin (5-HT3) antagonist antiemetics	ondansetron
-terol	Bronchodilators	salmeterol
-azepam	Benzodiazepines of the diazepam type	lorazepam
-oxetine	Serotonin or noradrenaline reuptake inhibitors	fluoxetine
-triptan	Migraine drugs (serotonin 5-HT1 agonists)	sumatriptan
-cillin	Penicillins	amoxicillin
cef-	Cephalosporins	cefazolin
-oxacin	Quinolone antibacterials	ciprofloxacin
-cycline	Tetracyclines	doxycycline
-conazole	Systemic antifungals	fluconazole
-gliptin, -gliflozin	Antihyperglycemics	sitagliptin, empagliflozin
-caine	Local anesthetics	lidocaine

What to check before you give it

Drug	Before the dose
Digoxin	Count the apical pulse for a full minute. Withhold the dose and notify the prescriber if it is below 60. Check the potassium: hypokalemia raises the risk of toxicity.
Beta blockers (metoprolol)	Check the apical pulse and blood pressure. Withhold and call the provider if the heart rate is below 60, unless other limits are ordered.
Clonidine and other antihypertensives	Check the blood pressure and pulse before each dose.
Warfarin	Check the PT or INR. The therapeutic INR is 2.0 to 3.5, depending on the reason for treatment.
IV heparin	Check the PTT. Read the vial strength carefully: fatal errors have come from the wrong heparin product.
Nitroglycerin	Ask about sildenafil or a similar drug in the last 24 hours. Together they can cause a dangerous fall in blood pressure.
Metformin	Check kidney function. Expect it to be held for a scan that uses iodinated contrast.
Insulin	Check the blood glucose. Know the signs of hypoglycemia and your protocol for treating it.
Aminoglycosides (gentamicin)	Check that peak and trough levels are ordered. Watch kidney function.
Lithium	Check the lithium level and the sodium. Dehydration, sodium loss and diuretics raise the risk of toxicity.

Adverse effects to watch for

Drug or class	Watch for
ACE inhibitors	Cough, hyperkalemia, low blood pressure, angioedema. Swelling of the face or trouble breathing is an emergency. Avoid salt substitutes.
Beta blockers	Slow heart rate, low blood pressure, worsening heart failure. They mask the usual signs of hypoglycemia in clients with diabetes.
Loop diuretics (furosemide)	Dehydration, low blood pressure, hypokalemia. Given too fast by IV, furosemide can damage hearing.
Statins (atorvastatin)	Muscle pain, tenderness or weakness, which can mean rhabdomyolysis. Liver function is monitored. No grapefruit juice.
Heparin	Bleeding. Heparin-induced thrombocytopenia: the platelet count falls by 30% or more.
Warfarin	Bleeding. Harm to the fetus in pregnancy.
Opioids (morphine)	Respiratory depression is the main risk. Also sedation, low blood pressure, constipation, nausea.
Aminoglycosides	Kidney damage, hearing damage, nerve damage.
Nitroglycerin	Low blood pressure, headache, flushing, dizziness.
Corticosteroids, long term	High blood glucose, infection risk, osteoporosis, adrenal suppression.
Phenytoin	Gum overgrowth. A rash can be the first sign of a severe skin reaction: stop the drug and report it.
SSRIs and SNRIs	Serotonin syndrome: agitation, fast heart rate, high temperature, overactive reflexes. Watch for suicidal thoughts when the drug or the dose is new.
MAOIs	Hypertensive crisis with foods that contain tyramine or with stimulant drugs.
Metformin	It does not cause hypoglycemia on its own, unlike sulfonylureas. It is contraindicated in kidney disease.

Nitroglycerin under the tongue has its own teaching: one tablet every 5 minutes, up to three tablets in 15 minutes. If the chest pain is not relieved after the first tablet, the client calls 911.

Antidotes and reversal agents

Drug or poison	Antidote
Opioids	Naloxone
Benzodiazepines	Flumazenil, used with caution
Heparin	Protamine sulfate
Warfarin	Vitamin K. Fresh frozen plasma or prothrombin complex concentrate when urgent
Acetaminophen	N-acetylcysteine
Digoxin	Digoxin-specific Fab fragments
Beta blockers	Glucagon
Calcium channel blockers	Calcium, and high-dose IV insulin with glucose
Iron	Deferoxamine
Isoniazid	Pyridoxine (vitamin B6)
Organophosphates	Atropine and pralidoxime
Methotrexate	Leucovorin (folinic acid)
Methanol or ethylene glycol	Fomepizole
Tricyclic antidepressants	Sodium bicarbonate
Sulfonylureas	Octreotide

Therapeutic drug levels

These are the ranges MedlinePlus lists. Laboratories differ slightly, and a few classroom ranges differ too. Where they do, the table says so. Learn the range your course teaches and read the range on the lab report.

Drug	Therapeutic range
Digoxin	0.8 to 2.0 ng/mL
Lithium	0.5 to 1.2 mEq/L (mmol/L), drawn 12 hours after a dose. Open RN teaches 0.8 to 1.2 and warns that toxicity can occur near 1.5.
Phenytoin	10 to 20 mcg/mL
Theophylline	8 to 20 mcg/mL
Carbamazepine	4 to 12 mcg/mL
Valproic acid	50 to 100 mcg/mL
Gentamicin	Peak 5 to 10 mcg/mL. Trough 0.5 to 2 mcg/mL

Drugs you do not stop abruptly

Long-term corticosteroids. Stopping suddenly risks an Addisonian crisis. The dose is tapered.
Clonidine. Stopping suddenly can cause rebound hypertension.
Phenytoin. Stopping suddenly can cause status epilepticus.

How to use this sheet

Take one table a day. Cover a column and recall it before you look.
Follow each table with practice questions on the same drugs, and read the rationales.
Pharmacology is 13 to 19% of the NCLEX-RN, 10 to 16% of the NCLEX-PN and 14 to 20% of REx-PN. The study plan builder gives it hours to match.

This sheet lists facts. To learn the reasons behind them, use Medibara's lessons. Each one is a short video on a single topic that gives you the mechanism, the nursing action and the signs to watch for, and questions on it follow in your exam's format. The lesson on potassium and the ECG shows what low potassium does to the heart and warns that digoxin toxicity arrives faster. That is the reason the digoxin row above tells you to check the potassium. You can play the lesson in the demo on the Medibara home page.

When a rationale and this sheet seem to disagree, ask Cappy, the tutor in the app. It answers from the lesson and shows where the answer comes from. Start learning on Medibara.

For potassium and the heart, see hyperkalemia ECG changes and hypokalemia ECG changes. For memory aids, see nursing mnemonics.

Sources