Skip to main content

Drug Interactions between allopurinol and theophylline

This report displays the potential drug interactions for the following 2 drugs:

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

allopurinol theophylline

Applies to: allopurinol and theophylline

Consumer information for this interaction is not currently available.

MONITOR: Allopurinol may inhibit the metabolism of xanthines (e.g., theophylline), possibly increasing serum concentrations and the risk of toxicity. When theophylline was coadministered with allopurinol, a 25% increase in steady-state theophylline serum concentrations were observed. This interaction may be more likely to occur with daily allopurinol doses of 600 mg or more. The mechanism may related to allopurinol's inhibition of xanthine oxidase, an enzyme involved in the metabolism of theophylline.

MANAGEMENT: Closer clinical and laboratory monitoring for adverse effects is advised if theophylline is used concomitantly with allopurinol. Additionally, theophylline levels should be more closely monitored following the initiation or discontinuation of allopurinol treatment, and the theophylline dosage adjusted as necessary in accordance with the prescribing information. Patients should be advised to report any signs of theophylline toxicity to their doctor (e.g., nausea, vomiting, diarrhea, headache, restlessness, insomnia, or irregular heartbeat).

Drug and food interactions

Moderate

allopurinol food

Applies to: allopurinol

Consumer information for this interaction is not currently available.

ADJUST DOSING INTERVAL: The tolerability of allopurinol may be improved by giving it after a meal. Additionally, when the dose is greater than 300 mg, dividing the total daily dose into smaller doses administered more often may be appropriate to help minimize gastrointestinal irritation.

MONITOR: Concomitant use of allopurinol with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: To improve tolerability, some manufacturers suggest administering allopurinol after a meal. Additionally, if the daily dose is greater than 300 mg, administering allopurinol in divided doses may help reduce gastrointestinal intolerance. Patients should also be counseled to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.

Moderate

theophylline food

Applies to: theophylline

Both smoking and excessive caffeine consumption can alter the blood levels of theophylline, which may affect the dosing. Tobacco and marijuana smoke (including secondhand exposure) generally reduces, while caffeine increases, blood levels. In addition, caffeine is a stimulant and may add to the side effects of theophylline such as headache, insomnia, and increases in blood pressure and heart rate. It is best to avoid smoking and to limit caffeine consumption during theophylline therapy. Talk to a healthcare professional if you have any questions or concerns. If you start smoking or undergo smoking cessation, your doctor may need to monitor your blood levels more closely to determine if you need a dose adjustment of theophylline. You should stop taking theophylline and seek medical attention if you experience potential signs and symptoms of excessive drug levels such as nausea, vomiting, persistent headache, insomnia, and rapid heartbeat. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

When theophylline is given with enteral (tube) feedings, blood levels may be decreased due to interference with its absorption. This may reduce the effectiveness of the medication. To minimize potential for interaction, you may interrupt the feeding for one hour before and one hour after the theophylline dose. You may need more frequent blood tests to monitor theophylline levels.

Switch to professional interaction data

Moderate

theophylline food

Applies to: theophylline

Ask your doctor before using theophylline together with caffeine. Using these medications together may increase some of the side effects of theophylline. This can cause nausea, vomiting, insomnia, tremors, restlessness, uneven heartbeats, and seizure (convulsions). Avoid drinks or foods that contain caffeine, such as coffee, tea, cola, and chocolate. You may need a dose adjustment or special test if you use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Switch to professional interaction data

Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.


Report options

Loading...
QR code containing a link to this page

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.