mexiletine 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 mexiletine and theophylline. 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
Concurrent use of mexiletine and theophylline may lead to increased plasma theophylline levels. One controlled study in eight normal subjects showed a 72% mean increase (range 35 to 136%) in plasma theophylline levels. Theophylline plasma levels returned to pre-mexiletine values within 48 hours after discontinuing mexiletine.
Mexitil
Theo-24, Elixophyllin
Mexiletine is a medicine used to treat life-threatening heart rhythm problems. It helps to stabilize your heartbeat.
Theophylline is a medicine that helps you breathe easier. It treats the symptoms of asthma and other lung problems.
Mexiletine is used to treat serious, life-threatening ventricular arrhythmias, like sustained ventricular tachycardia. These are problems with the rhythm of the lower chambers of your heart. It is generally not recommended for less severe arrhythmias or asymptomatic premature ventricular contractions.
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.
Mexiletine belongs to a class of drugs called antiarrhythmics. It works by slowing down the electrical signals in your heart. This helps to make your heartbeat more regular.
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.
- • Nausea
- • Vomiting
- • Heartburn
- • Dizziness
- • Lightheadedness
- • Nausea
- • Vomiting
- • Headache
- • Trouble sleeping (insomnia)
- Fatigue 31
- Ventricular Tachycardia 31
- Dyspnoea 26
- Nausea 24
- Poor Quality Sleep 24
- Dyspnoea 2,273
- Asthma 1,942
- Pneumonia 1,318
- Wheezing 1,306
- Vomiting 1,101
Mexiletine may increase the risk of death or cardiac arrest in some patients with a history of heart attack. It should only be used for life-threatening ventricular arrhythmias. This medicine can also cause liver problems, especially if you have congestive heart failure or ischemia.
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.
Tell your doctor if you are pregnant or plan to become pregnant. The effects of mexiletine during pregnancy are not fully known. Talk to your doctor about the risks and benefits of taking this medicine while pregnant or breastfeeding.
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.
How to Read This mexiletine vs theophylline Comparison
mexiletine is classified in the Class IB Antiarrhythmic 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, mexiletine has 136 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 minor interaction flagged in FDA labeling, attributed to mexiletine can slow down the removal of theophylline from your body, which makes the amount of theophylline in your blood go up.. 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 mexiletine or theophylline.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.