isradipine vs theophylline

According to this portal's Publishing Organization, this page was last reviewed in August 2026 against our methodology. Figures and extracts on this site, including tables above 1,000 rows when the corpus is that large, are the publisher's responsibility.

Side-by-side comparison of isradipine 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

albuterol, systemic and inhaled mebendazole amoxicillin medroxyprogesterone ampicillin, with or without sulbactam methylprednisolone atenolol metronidazole azithromycin metoprolol caffeine, dietary ingestion nadolol cefaclor nifedipine co-trimoxazole (trimethoprim and sulfamethoxazole) nizatidine diltiazem norfloxacin dirithromycin ofloxacin enflurane omeprazole famotidine prednisone, prednisolone felodipine ranitidine finasteride rifabutin hydrocortisone roxithromycin isoflurane Sorbitol (purgative doses do not inhibit theophylline absorption) isoniazid sucralfate isradipine terbutaline,...

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

Isradipine is a drug that helps lower high blood pressure. It belongs to a class of drugs called calcium channel blockers.

theophylline

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

What It Treats
isradipine

Isradipine capsules are used to treat high blood pressure. You can take it alone or with a thiazide diuretic (water pill). It may take 2 to 4 weeks to see the full effect.

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
isradipine

Isradipine blocks calcium from entering certain cells. This action relaxes blood vessels, which lowers blood pressure. Lowering blood pressure helps prevent strokes, heart attacks, and kidney problems.

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
isradipine
  • Headache
  • Dizziness
  • Swelling in ankles or feet
  • Feeling your heart beat rapidly or irregularly
  • Fatigue
theophylline
  • Nausea
  • Vomiting
  • Headache
  • Trouble sleeping (insomnia)
FAERS Reports
isradipine
  • Drug Interaction 32
  • Dyspnoea 31
  • Hypertension 29
  • Acute Kidney Injury 26
  • Nausea 26
theophylline
  • Dyspnoea 2,273
  • Asthma 1,942
  • Pneumonia 1,318
  • Wheezing 1,306
  • Vomiting 1,101
Serious Warnings
isradipine

If you are taking cimetidine, your doctor should watch you closely for side effects when you start isradipine. If you are taking rifampicin, isradipine 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
isradipine

Tell your doctor if you are pregnant or plan to become pregnant. It is not known if isradipine will harm your unborn baby. Talk to your doctor about the risks and benefits of taking isradipine while breastfeeding.

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 isradipine vs theophylline Comparison

isradipine 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, isradipine has 144 submissions while theophylline has 7,940. 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 medication does not affect the speed at which your body breaks down theophylline or clears it from your blood.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for isradipine or theophylline.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.