Theo Dur (Theophylline SR) Shopper Approved

Prescription Prescription Required FormationFormulation: 12H ER Scored Tablet

Theo Dur

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Prescription Prescription Required FormationFormulation: 12H ER Scored Tablet

Theophylline SR

(Generic Alternative)

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Theophylline SR is an oral medication used to treat lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). Theo-Dur contains the active ingredient theophylline, which belongs to a group of medicines known as bronchodilators. It works by relaxing the muscles in the bronchial tubes, allowing air to flow more easily through them.

Theophylline must be used regularly to prevent wheezing and shortness of breath. It does not work right away and should not be used to relieve sudden breathing problems. If sudden shortness of breath occurs, use your quick-relief inhaler as prescribed.

Uses and Dosage

Theophylline SR comes in the form of a 12-hour scored tablet to be taken by mouth as directed by your doctor, usually once or twice daily. Different manufacturers may have different recommendations for taking the tablet, so it is important to ask your doctor or pharmacist about the best time(s) to take your brand of theophylline and if you should take the drug with or without food.

Do not crush or chew the tablets, as doing so can release all the drugs at once, increasing the risk of side effects. Also, do not split the tablets unless your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing.

The dosage of Theo-Dur is based on your medical condition, response to treatment, age, weight, and other medications you may be taking. Your doctor may also conduct lab tests to measure your theophylline blood levels. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Be sure to tell your doctor and pharmacist about all the products you use, including prescription drugs, nonprescription drugs, and herbal products.

Certain dietary changes, such as high protein/low carbohydrate or high carbohydrate/low protein, may change the effect of theophylline. Tell your doctor if you have any major changes in your diet, as your doctor may need to adjust your dose accordingly.

Take the tablet regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not increase your dose, take this drug more often, or stop taking it without first consulting your doctor. Suddenly stopping the medication can lead to withdrawal symptoms and a worsening of lung symptoms.

Side Effects

Common Side Effects of Theo Dur (Theophylline SR):

  • Diarrhea
  • Difficulty falling asleep or staying asleep
  • Headache
  • Irritability
  • Restlessness
  • Stomach pain
  • Upset stomach

Serious Side Effects of Theo Dur (Theophylline SR):

  • Increased or rapid heart rate
  • Irregular heartbeat
  • Rash
  • Seizures
  • Vomiting

Form and Strength

Theo Dur (Theophylline SR) is available in the following forms and strengths:

Theophylline SR: 12H ER Scored Tablet

  • 100 mg
  • 200 mg
  • 300 mg


  • Patients who are allergic to theophylline or any of its ingredients should not take Theo-Dur.
  • Closely follow dosing instructions and not exceed the recommended dose, as this can lead to serious side effects.
  • Patients with a history of seizures, heart disease, liver disease, or stomach ulcers should use Theo-Dur with caution.
  • Certain medications can interact with Theo-Dur and increase the risk of side effects, so patients should inform their doctor of any other medications they are taking.
  • Patients with a history of caffeine consumption, smoking, or excessive alcohol intake should use Theo-Dur with caution or avoid it altogether.
  • Patients with thyroid problems, diabetes mellitus, or high blood pressure should also use Theo-Dur with caution or avoid it altogether.
  • Theo-Dur may cause side effects such as nausea, vomiting, headaches, and stomach pain, which may become serious or persist over time. Patients who experience any serious or persistent side effects while taking Theo-Dur should notify their doctor immediately.
  • For patients to avoid drinking alcohol or taking medications that contain alcohol while taking Theo-Dur, as this can increase the risk of side effects or decrease the effectiveness of the medication.
  • Theo-Dur may interact with certain foods, such as broccoli, Brussels sprouts, chocolate, and tea, which contain substances that can increase the risk of side effects.
  • Theo-Dur can cause changes in heart rate and blood pressure and may put patients at risk for arrhythmias or heart attacks, so patients with heart disease or a history of heart problems should use Theo-Dur with caution.
  • Patients who are pregnant or breastfeeding should consult with their doctor before taking Theo-Dur.

Frequently Asked Questions (FAQ)

How often should I take Theo-Dur?

The dosing instructions for Theo-Dur vary depending on the patient's condition. Patients should follow the dosing instructions provided by their doctor or pharmacist.

Is Theo-Dur addictive?

No, Theo-Dur is not considered to be addictive.

What should I do if I miss a dose of Theo-Dur?

If you miss a dose of Theo-Dur, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up.

Can I stop taking Theo-Dur if my symptoms improve?

No, patients should not stop taking Theo-Dur without first consulting with their doctor. Suddenly stopping the medication can lead to withdrawal symptoms and a worsening of lung symptoms.


Additional information

Generic name:

Theophylline SR


12H ER Scored Tablet


100mg, 200mg, 300mg

Quantities Available:



Additional Information Book

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Online Pharmacies Canada has provided information from third parties intended to increase awareness and does not contain all the information about Theo Dur (Theophylline SR). Talk to your doctor or other qualified medical practitioners for medical attention or advice, or if you have any concerns about Theo Dur (Theophylline SR).