Theophylline and Verapamil: Drug Interaction Guide

Quick answer: This combination requires caution. Theophylline and Verapamil can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Theophylline interacts with Verapamil

Verapamil inhibits CYP1A2 and CYP3A4-mediated metabolism of theophylline, raising serum levels by approximately 20-50% and increasing the risk of nausea, tachyarrhythmia, and seizures.

What you should do

Monitor theophylline serum levels after initiating or stopping verapamil and adjust the theophylline dose to remain within 10-20 mg/L.

Key facts

Severity

Moderate — caution required

Mechanism

Verapamil inhibits CYP1A2 and CYP3A4-mediated metabolism of theophylline, raising serum levels by approximately 20-50% a...

Action

Monitor theophylline serum levels after initiating or stopping verapamil and adjust the theophylline dose to remain with...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Theophylline and Verapamil together?

With caution. Monitor theophylline serum levels after initiating or stopping verapamil and adjust the theophylline dose to remain within 10-20 mg/L.

What is the severity of this interaction?

The interaction between Theophylline and Verapamil is classified as Moderate — caution required. Verapamil inhibits CYP1A2 and CYP3A4-mediated metabolism of theophylline, raising serum levels by approximately 20-50% and increasing the risk of nausea, tachyarrhythmia, and seizures.

What should I do if I'm prescribed both?

Monitor theophylline serum levels after initiating or stopping verapamil and adjust the theophylline dose to remain within 10-20 mg/L. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.