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felodipine vs theophylline

Side-by-side comparison of felodipine and theophylline. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

major Known Drug Interaction

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Recommendation: No dosage adjustment is typically required, but you should still report any unusual symptoms to your healthcare provider.

Drug Class
felodipine Calcium Channel Blocker
theophylline Methylxanthine Bronchodilator
Type
felodipine Prescription
theophylline Prescription
Summary
felodipine

Felodipine is a drug that lowers your blood pressure. Lowering blood pressure reduces the risk of strokes and heart attacks.

theophylline

Theophylline is a medicine that helps you breathe easier. It treats the symptoms of asthma and other lung problems.

What It Treats
felodipine

Felodipine treats high blood pressure (hypertension). Lowering your blood pressure helps prevent strokes and heart attacks. It's important to also manage other risk factors like cholesterol, diabetes, and smoking. You may need more than one medicine to control your blood pressure.

theophylline

Theophylline treats the symptoms of long-term asthma and other lung diseases. These include emphysema and chronic bronchitis, which make it hard to breathe. This medicine helps to open up your airways so you can breathe easier.

How It Works
felodipine

Felodipine is a calcium channel blocker. It works by relaxing and widening your blood vessels. This makes it easier for blood to flow, which lowers blood pressure.

theophylline

Theophylline is a bronchodilator. It works by relaxing the muscles in your airways. This allows more air to flow in and out of your lungs.

Common Side Effects
felodipine
  • Swelling in your ankles or feet
  • Headache
  • Flushing (redness of face)
  • Feeling tired
theophylline
  • Nausea
  • Vomiting
  • Headache
  • Trouble sleeping (insomnia)
FAERS Reports
felodipine
  • Feeling tired 1,050
  • Difficulty breathing 953
  • Feeling lightheaded 946
  • Loose stools 846
  • Feeling sick to your stomach 846
theophylline
  • Difficulty breathing 2,273
  • Asthma 1,942
  • Pneumonia 1,317
  • Wheezing 1,306
  • Vomiting 1,101
Serious Warnings
felodipine

If you take certain medicines like ketoconazole, itraconazole, or erythromycin, talk to your doctor. These drugs can greatly increase the amount of felodipine in your blood, leading to unwanted effects. Also, if you take anticonvulsants like phenytoin, carbamazepine, or phenobarbital, felodipine may not work as well.

theophylline

If your theophylline levels get too high in your blood, it can cause serious side effects. These include severe vomiting, irregular heartbeats, and seizures. These can be life-threatening.

Pregnancy
felodipine

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if felodipine will harm your unborn baby. Talk to your doctor about breastfeeding while taking felodipine.

theophylline

It is not known if theophylline can harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if theophylline passes into breast milk, so talk to your doctor if you are breastfeeding.

Also Compare, Nearby Drugs

How to Read This felodipine vs theophylline Comparison

felodipine is classified in the Calcium Channel Blocker drug class, while theophylline sits within the Methylxanthine Bronchodilator 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, felodipine has 4,641 submissions while theophylline has 7,939. 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 major interaction flagged in FDA labeling, attributed to this blood pressure drug does not change the amount of theophylline that stays in your blood or how the liver handles it.. 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 felodipine and theophylline - 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.