👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Pharmacological Therapies🔖 Free to read, print, and share
Also known as: Cardizem · Tiazac · calcium channel blocker
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Use this quick-reference guide to spot, treat, and prevent Diltiazem on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
📌 Uses
HTN, angina, A-fib/SVT rate control
Blocks Ca → ↓ HR, ↓ contractility
🩺 Signs
Bradycardia, hypotension, edema
Dizziness, constipation, flushing
🚩 Report
HR < 60 → hold dose
SBP < 90, new SOB/swelling
📌 Avoid
NEVER w/ IV beta-blocker → asystole
Heart block, HFrEF caution
No grapefruit juice → ↑ levels
🎓 Teach
Check pulse before each dose
Rise slowly, ↑ fiber/fluids
📚 Diltiazem — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Diltiazem is a non-dihydropyridine calcium channel blocker used for rate control in atrial fibrillation and flutter, supraventricular tachycardia, hypertension, and angina. It slows AV node conduction, reduces heart rate, and relaxes vascular smooth muscle to lower blood pressure. Both IV and oral forms are used.
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Key points
Understand these first
Slows AV nodal conduction and heart rate, making it effective for rate control in atrial fibrillation.
Lowers blood pressure through arterial vasodilation and can cause bradycardia and hypotension.
Should not be combined with IV beta blockers because of additive risk of profound bradycardia and heart block.
Contraindicated in second- or third-degree heart block (without a pacemaker) and in cardiogenic shock.
Grapefruit juice increases drug levels by inhibiting metabolism.
Extended-release tablets must be swallowed whole, not crushed or chewed.
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Nursing priorities
What to do, in order
Check apical heart rate and blood pressure before administration; hold and notify the provider if heart rate is below 60 or systolic BP is below 90 mmHg.
Place the patient on continuous ECG monitoring during IV administration.
Assess for signs of heart failure and peripheral edema with ongoing therapy.
Teach patients to swallow extended-release forms whole and to avoid grapefruit.
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Red flags — report now
Escalate immediately
Hold and report heart rate below 60 beats per minute or systolic BP below 90 mmHg.
Report new heart block, severe bradycardia, syncope, or worsening heart failure.
Never give concurrently with IV beta blockers due to the risk of cardiac standstill.
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Patient teaching
What patients must know
Take your pulse as instructed and report a rate below 60 or feelings of fainting.
Swallow extended-release tablets whole; do not crush, chew, or split them.
Avoid grapefruit and grapefruit juice while on this medication.
Rise slowly to prevent dizziness from low blood pressure.
Do not stop the drug abruptly, as angina or rapid heart rate can rebound.
❓ Diltiazem: NCLEX FAQs
What are the priority nursing interventions for Diltiazem?
Check apical heart rate and blood pressure before administration; hold and notify the provider if heart rate is below 60 or systolic BP is below 90 mmHg. Place the patient on continuous ECG monitoring during IV administration. Assess for signs of heart failure and peripheral edema with ongoing therapy. Teach patients to swallow extended-release forms whole and to avoid grapefruit.
What are the warning signs of Diltiazem a nurse must report?
Hold and report heart rate below 60 beats per minute or systolic BP below 90 mmHg. Report new heart block, severe bradycardia, syncope, or worsening heart failure. Never give concurrently with IV beta blockers due to the risk of cardiac standstill.
What do I need to know about Diltiazem for the NCLEX?
Slows AV nodal conduction and heart rate, making it effective for rate control in atrial fibrillation. Lowers blood pressure through arterial vasodilation and can cause bradycardia and hypotension. Should not be combined with IV beta blockers because of additive risk of profound bradycardia and heart block. Contraindicated in second- or third-degree heart block (without a pacemaker) and in cardiogenic shock.
What patient teaching is important for Diltiazem?
Take your pulse as instructed and report a rate below 60 or feelings of fainting. Swallow extended-release tablets whole; do not crush, chew, or split them. Avoid grapefruit and grapefruit juice while on this medication. Rise slowly to prevent dizziness from low blood pressure.
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Quick Tip
Slows AV nodal conduction and heart rate, making it effective for rate control in atrial fibrillation.