Theo-Dur (Theophylline)

(℞) Prescription Required

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Theophylline SR 100mg

Product of Canada
Manufactured by: Teva Pharmaceuticals
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Theophylline SR 100mg
Product of Canada
Manufactured by Teva Pharmaceuticals
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Theophylline SR 200mg

Product of Canada
Manufactured by: Apotex Inc
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Theophylline SR 200mg
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Manufactured by Apotex Inc
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Theo-Dur 200mg

Product of Australia
Manufactured by: iNova
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Theo-Dur is also marketed as Nuelin SR
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Theo-Dur 200mg
Product of Australia
Manufactured by iNova
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Theo-Dur (Theophylline) Dosage and Side Effects

THEO-DUR is used to treat airflow obstruction symptoms such as wheezing, shortness of breath, and chest tightness related to asthma and lung diseases, including emphysema and chronic bronchitis.

Warnings and Precautions

THEO-DUR can also worsen some conditions, so you shouldn't use it if you have:

  • Ulcers
  • Seizure disorders
  • Some forms of cardiac arrhythmias (abnormal heart rate)

Under certain conditions, the drug can remain in your body longer than normal and build up to unsafe levels, resulting in fatal toxic reactions.

In these cases, you should not take THEO-DUR unless the benefits clearly outweigh the risk, and then your doctor will have to carefully decide on your dosage and monitor your blood for levels of the drug.

The conditions that can lead to a deadly toxic reaction include:

  • Being younger than 1 year old, or older than 60 years
  • Congestive heart failure and right-sided heart failure (cor pulmonale) that typically arises from high blood pressure
  • A buildup of fluid in the lungs (acute pulmonary edema)
  • Liver disease, acute hepatitis, or cirrhosis (scarring of the liver)
  • Reduced kidney function
  • Cystic fibrosis
  • A fever of 102 Fahrenheit or more that lasts 24 hours, or a low fever that lasts longer than a day
  • A high-carbohydrate, low-protein diet
  • Thyroid disease
  • A state of physical shutdown called shock
  • Sepsis (blood infection) with multi-organ failure
  • The flu
  • Tobacco and marijuana smoking
  • Stopping smoking
  • Taking or stopping certain drugs while on THEO-DUR

You need to be very careful about other drugs you are on or stop taking because of the same potentially fatal toxic reaction.

Pregnancy and THEO-DUR

Studies in animals have shown that the drug can cause birth defects, but no adequate and well-controlled studies have been conducted in pregnant women.

THEO-DUR should only be used during pregnancy if the potential benefits to the mother outweigh the risks to her unborn child.

THEO-DUR is excreted in breast milk, potentially causing irritability and other signs of mild toxicity in breastfeeding infants.

It's not likely to cause serious side effects in infants unless the breastfeeding mother has very high concentrations of the drug in her body.

Nonetheless, if you are breastfeeding your child, you shouldn't take THEO-DUR unless the potential benefits outweigh the risks, and then only under the guidance of your doctor.

Side Effects

Common Side Effects of THEO-DUR

Although these effects are common, they can be serious and are likely to mean your doctor should change your dosage.

Tell your doctor if you experience any of the following, and if the effect becomes severe, get immediate medical help:

  • Nausea and vomiting
  • Headache
  • Upset stomach
  • Loss of appetite
  • Fast, strong heartbeat
  • Irregular heartbeat (arrhythmia): usually there are no symptoms, but it can cause a fluttering feeling, dizziness, shortness of breath, chest pain, heartbeats that feel too fast or slow, or fainting
  • Symptoms similar to how you feel when you've had too much coffee, such as trouble falling asleep (insomnia), restlessness, and irritability.
  • Skin rash

Severe Side Effects of THEO-DUR

You need immediate emergency medical treatment if you are experiencing:

  • Seizures

Rare Side Effects of THEO-DUR

Tell your doctor right away or get emergency medical help if you experience any of the following more rare side effects:

  • Stomach pain
  • Anxiety
  • Diarrhea
  • Dizziness
  • Tremors
  • Urination issues, including frequent or infrequent urination and hyperuricemia (high levels of uric acid)
  • Allergic reaction
  • Reflux

Interactions with this medication

Some drugs can affect your body's ability to process THEO-DUR, potentially causing it to build up to unsafe levels and become toxic.

In addition, THEO-DUR interacts with a wide variety of other drugs, so it's especially important to tell your doctor about any medications, illegal or recreational drugs, herbal remedies, and supplements you're taking, even if you are smoking tobacco.

The following drugs are especially important to tell your doctor about before you take THEO-DUR:

  • Adenosine (Adenoscan)
  • Allopurinol (Zyloprim)
  • Aminoglutethimide (Cytadren)
  • Carbamazepine (Tegretol)
  • Cimetidine
  • Ciprofloxacin (Cipro)
  • Clarithromycin (Biaxin)
  • Diazepam (Valium)
  • Disulfiram (Antabuse)
  • Enoxacin
  • Ephedrine
  • Erythromycin (Ery-tab)
  • Estrogen-containing oral contraceptives
  • Flurazepam (Dalmane)
  • Fluvoxamine (Luvox)
  • Halothane (Fluothane)
  • Interferon
  • Isoproterenol (Isuprel)
  • Ketamine (Ketalar)
  • Lithium
  • Lorazepam (Ativan)
  • Methotrexate (Trexall)
  • Mexiletine (Mexitil)
  • Midazolam
  • Moricizine
  • Pancuronium (Pavulon)
  • Pentoxifylline (Trenal)
  • Phenobarbital
  • Phenytoin (Dilantin)
  • Propafenone (Rythmol)
  • Propranolol (Inderal)
  • Rifampin (Rifadin)
  • Ritonavir
  • Roflumilast (Daliresp)
  • St. John's wort
  • Sulfinpyrazone (Anturane)
  • Tacrine (Cognex)
  • Thiabendazole (Mintezol)
  • Ticlopidine (Ticlid)
  • Troleandomycin (Tao)
  • Verapamil (Calan)

THEO-DUR and Alcohol

Drinking alcohol while taking THEO-DUR may cause the drug to remain in your body for up to 30 percent longer, which can lead to serious toxic effects.

Therefore, you should not drink alcohol when taking THEO-DUR.

Proper Use of this medication

A sudden overdose from taking too much THEO-DUR all at once is rare.

A chronic overdose, however, is not rare, especially if you have been taking a dose that is a little too high for a long time, or if your dose has recently been increased.

An overdose of THEO-DUR may cause slow heart rate, abnormal heart rate, seizures, circulatory system failure, and death.

If you suspect an overdose, you should contact a poison-control center or emergency room immediately.

Missed Dose of THEO-DUR

Missing a dose of THEO-DUR may cause your asthma or bronchitis symptoms to reappear.

If you remember your missed dose within 6 hours of your regular dosing time, take your missed dose immediately.

Take half a dose if you remember the missed dose between 6 and 18 hours after your regular time.

If more than 18 hours have passed since your missed dose, skip it and take your next dose at your regular dosing time.

Never double-up a dose of THEO-DUR.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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