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(theophylline - potassium iodide - guaifenesin - mepyramine)

How does this medication work? What will it do for me?

This is a combination medication that contains 4 medications: theophylline, potassium iodide, guaifenesin, and mepyramine. Theophylline belongs to the group of medications called bronchodilators; potassium iodide and guaifenesin belongs to the group of medications called expectorants; and mepyramine belongs to the group of medications called antihistamines.

The ingredients of this medication are used together to treat the symptoms of bronchial asthma, chronic bronchitis, emphysema, and other diseases involving constriction of the airways.

This medication helps to ease the cough, wheezing, shortness of breath, and troubled breathing associated with these conditions by allowing relaxation of the tubes (bronchi) of the airways, decreasing mucus thickness, and allowing for easier removal of mucus from the breathing passages. These actions allow increased amounts of air to flow through the airways.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

How should I use this medication?

The recommended adult dose of this medication is 10 mL 4 times daily. For children 6 years of age and over, the dose is 2.5 mL to 5 mL 3 times daily (every 8 hours). For children under 6 years of age, the dose is 2.5 mL per 6.8 kg of body weight 2 to 3 times daily at 8-hour intervals.

Use an oral syringe to measure each dose of the syrup, as it gives a more accurate measurement than household teaspoons.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

Do not take more of this medication than prescribed, even if your breathing does not get better with your prescribed dose. This is because the levels of this medication in the body at which signs of overdose occur are not as high as with most other medications. If your breathing does not improve, or gets worse, call your doctor at once.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

If this medication causes stomach upset, your doctor or pharmacist may suggest that you take it with food.

Store this medication at room temperature and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

What form(s) does this medication come in?

ratio-Theo-Bronc syrup is no longer being manufactured for sale in Canada. For brands that may still be available, search under theophylline - potassium iodide - guaifenesin - mepyramine. This article is being kept available for reference purposes only. If you are using this medication, speak with your doctor or pharmacist for information about your treatment options.

Who should NOT take this medication?

Do not take this medication if you:

  • are allergic to theophylline or related medications (i.e., xanthines), guaifenesin, potassium iodide, mepyramine, or any ingredients of this medication
  • have an ulcer in the stomach or intestines
  • have heart disease or any condition where stimulation of the heart muscle might be harmful
  • have hyperthyroidism (overactive thyroid)

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • dizziness
  • drowsiness
  • fast heartbeat
  • headache
  • nausea
  • nervousness
  • trouble sleeping

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • heartburn

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • symptoms of a severe allergic reaction (e.g., hives; difficulty breathing; swelling of the face, mouth, tongue, or throat)
  • symptoms of theophylline toxicity (too much theophylline in the blood):
    • confusion or change in behaviour
    • dark or bloody vomit
    • diarrhea
    • excitement or irritability alternating with drowsiness
    • extreme thirst
    • fast, pounding, or irregular heartbeat
    • fever
    • increased urination
    • loss of appetite
    • nervousness or restlessness (continuing)
    • ringing in the ears
    • seeing flashes of light
    • seizures
    • trembling (continuing)
    • trouble sleeping
    • vomiting

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Carcinoid syndrome: This medication may interfere with the diagnosis of carcinoid syndrome. If you are being tested for carcinoid syndrome your doctor may suggest that you stop taking this medication 24 hours before testing.

High blood pressure: This medication may worsen high blood pressure. If you have high blood pressure, discuss with doctor whether any special monitoring is needed.

Smoking: One of the ingredients of this medication, theophylline, is cleared faster from the body if you smoke. Make sure you tell your doctor if you smoke or change the amount that you smoke (less or more) while you are taking this medication.

Theophylline blood levels: If you have reduced liver or kidney function, are over 55 years of age (especially if you are male and have chronic lung problems), have heart failure or are taking certain medications (e.g., erythromycin, clarithromycin, cimetidine, fluvoxamine), you may not clear theophylline from your body as quickly as most people and your doctor may want to check the level of theophylline in your blood. Your doctor may also want to check your blood levels if you have the flu, a viral infection, or a fever.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: Theophylline and potassium iodide pass into breast milk. It is not known if mepyramine and guaifenesin pass into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Children are especially sensitive to some of the side effects of this medication. You must be particularly careful in giving the correct dose of this medication to a child. If you are not sure about how to measure the dose for a child or are not sure how much you are supposed to give, do not give this medication until you have spoken to a doctor or pharmacist.

What other drugs could interact with this medication?

There may be an interaction between theophylline - potassium iodide - guaifenesin - mepyramine and any of the following:

  • ACE inhibitors (e.g., enalapril, lisinopril, ramipril, trandolapril)
  • allopurinol
  • angiotensin II receptor blockers (e.g., candesartan, irbesartan, losartan, valsartan) adenosine
  • barbiturates (e.g., phenobarbital)
  • benzodiazepines (e.g., clonazepam, diazepam, lorazepam)
  • carbamazepine
  • certain beta-blockers (e.g., propranolol, sotalol, timolol)
  • cimetidine
  • ciprofloxacin
  • clarithromycin
  • digoxin
  • diuretics (e.g., hydrochlorothiazide, furosemide, amiloride, spironolactone, triamterene)
  • droperidol
  • epinephrine
  • eplerenone
  • erythromycin
  • fluvoxamine
  • influenza vaccine
  • ketoconazole
  • lithium
  • marijuana
  • mexiletine
  • nefazodone
  • norfloxacin
  • ofloxacin
  • pancuronium
  • phenytoin
  • probenecid
  • protease inhibitors (e.g., atazanavir, ritonavir, saquinavir)
  • pseudoephedrine
  • quinidine
  • thyroid hormones
  • ticlopidine
  • tobacco
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

All material copyright MediResource Inc. 1996 – 2024. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source:

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