famotidine vs theophylline
Side-by-side comparison of famotidine 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,...
Recommendation: These medicines are generally safe to use together.
Pepcid
Theo-24, Elixophyllin
Famotidine (Pepcid) reduces stomach acid. It is used to treat ulcers, heartburn, and acid reflux.
Theophylline is a medicine that helps you breathe easier. It treats the symptoms of asthma and other lung problems.
This medicine treats active duodenal ulcers and active gastric ulcers. It also treats heartburn (nonerosive GERD) and erosive esophagitis (damage to the esophagus from acid reflux). Famotidine can also treat conditions where the stomach makes too much acid, like Zollinger-Ellison syndrome. It can also lower the risk of duodenal ulcers coming back.
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.
Famotidine is an H2 receptor antagonist. This means it blocks histamine, a substance that tells your stomach to make acid. By blocking histamine, famotidine reduces the amount of acid your stomach produces.
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.
- • Headache
- • Dizziness
- • Constipation
- • Diarrhea
- • Nausea
- • Vomiting
- • Headache
- • Trouble sleeping (insomnia)
- Feeling sick to your stomach 7,259
- Feeling tired 6,866
- Long-term kidney problems 6,644
- Loose, watery stools 6,448
- Difficulty breathing 5,203
- Difficulty breathing 2,273
- Asthma 1,942
- Pneumonia 1,317
- Wheezing 1,306
- Vomiting 1,101
In elderly patients and those with kidney problems, famotidine can cause confusion, delirium, or hallucinations. If you are elderly or have kidney problems, your doctor may prescribe a lower dose. Famotidine can hide the symptoms of stomach cancer. If your symptoms don't improve, tell your doctor.
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.
It is not known if famotidine will harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. Famotidine may pass into breast milk, but it's not expected to harm the baby. Talk to your doctor about breastfeeding while taking this medicine.
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.
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How to Read This famotidine vs theophylline Comparison
famotidine is classified in the H2 Receptor Antagonist 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 split between OTC and prescription status, which affects access and supervision.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, famotidine has 32,420 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 famotidine does not affect the amount of theophylline that stays in your blood.. 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 famotidine 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.