clonidine vs diltiazem
Side-by-side comparison of clonidine and diltiazem. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
Sinus bradycardia resulting in hospitalization and pacemaker insertion has been reported in association with the use of clonidine concomitantly with diltiazem or verapamil.
Recommendation: Your doctor should check your heart rate often to make sure it does not drop to a dangerous level.
Clonidine (Catapres) is a medicine used to treat high blood pressure. It can be used alone or with other blood pressure medicines.
Diltiazem is a medicine that helps lower high blood pressure and prevent chest pain. It belongs to a class of drugs called calcium channel blockers.
Clonidine is used to treat high blood pressure. High blood pressure can lead to heart disease, stroke, and kidney problems. This medicine helps to lower your blood pressure to a safer level.
Diltiazem is used to treat high blood pressure. It can be used alone or with other blood pressure medicines. Diltiazem also helps manage chronic stable angina (chest pain) and angina caused by spasms in the heart's blood vessels.
Clonidine works in the brain to lower blood pressure. It tells your blood vessels to relax and widen. This makes it easier for blood to flow through your body, which lowers blood pressure.
Diltiazem works by relaxing blood vessels, which lowers blood pressure. It also reduces the heart's workload, which can prevent chest pain. This medicine blocks calcium from entering heart and blood vessel cells.
- • Dry mouth (occurs in about 40 out of 100 people)
- • Drowsiness (occurs in about 33 out of 100 people)
- • Dizziness (occurs in about 16 out of 100 people)
- • Constipation (occurs in about 10 out of 100 people)
- • Feeling sleepy or sedated (occurs in about 10 out of 100 people)
- • Swelling in your ankles or feet
- • Headache
- • Dizziness
- • Slow heart rate
- • Constipation
- Pain 3,038
- Tiredness 2,922
- Feeling sick to your stomach 2,918
- Headache 2,799
- High blood pressure 2,597
- Shortness of breath 3,200
- Tiredness 2,637
- Feeling sick to your stomach 2,372
- Discomfort 2,364
- Feeling lightheaded 2,089
If you suddenly stop taking clonidine, your blood pressure may increase. This can cause serious problems. Talk to your doctor before stopping this medicine.
Diltiazem can interact with other heart medications. Tell your doctor if you take beta-blockers or digoxin. Using diltiazem with these drugs can cause heart problems. Your doctor may need to adjust your dosages.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if clonidine will harm your unborn baby. Talk to your doctor if you are breastfeeding.
Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. It is not known if diltiazem will harm your unborn baby. Diltiazem passes into breast milk, so talk to your doctor about breastfeeding while taking this medicine.
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How to Read This clonidine vs diltiazem Comparison
clonidine is classified in the Central Alpha-2 Agonist drug class, while diltiazem sits within the Calcium Channel Blocker class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, clonidine has 14,274 submissions while diltiazem has 12,662. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to both medicines slow down the heart, and taking them together can make the heart beat too slowly.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between clonidine and diltiazem - always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.