Theophylline helps relieve symptoms such as cough, wheeze and shortness of breath.
Make sure that you receive the same brand of theophylline each time you collect your prescription.
Swallow the tablets or capsules whole - do not crush or chew them.
If you are a smoker or drink alcohol, ask your doctor for advice, as these can affect the levels of theophylline in your blood.
|Type of medicine||Xanthine bronchodilator|
|Used for||Lung-related problems such as asthma and chronic obstructive pulmonary disease (COPD); sometimes used to treat heart failure|
|Also called||Nuelin SA®; Slo-Phyllin®; Uniphyllin Continus®|
|Available as||Modified-release tablets and capsules|
Theophylline is an oral bronchodilator medicine which is prescribed for people with breathing problems, such as asthma and chronic obstructive pulmonary disease (COPD). It is a medicine that you take by mouth, as a tablet or capsule.
Theophylline works by opening up the air passages in your lungs so that air can flow into your lungs more freely. This makes breathing easier and helps relieve symptoms such as coughing, wheezing and shortness of breath.
It is important always to stick to the same brand of theophylline. This is because the amount of theophylline absorbed by your body varies greatly between brands. If you start taking a different brand to the one you normally have, you may be getting too much or too little theophylline.
Before taking theophylline
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking theophylline it is important that your doctor or pharmacist knows:
- If you are pregnant, trying for a baby or breastfeeding.
- If you have a heart condition or have had a heart attack.
- If you have kidney or liver problems.
- If you have an overactive thyroid gland (hyperthyroidism).
- If you have high blood pressure.
- If you have a stomach ulcer.
- If you drink alcohol, or smoke.
- If you have epilepsy.
- If you are currently unwell with a high temperature (fever).
- If you have a rare inherited blood disorder called porphyria.
- If you have been told you have low levels of potassium in your blood.
- If you are taking or using any other medicines or inhalers. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine.
How to take theophylline
- Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about theophylline and a full list of side-effects which you may experience from taking it.
- Theophylline is usually taken twice a day, although some doctors may prescribe just one dose a day. Take the tablets/capsules exactly as your doctor tells you to.
- For twice daily doses, always try to take your doses 12 hours apart and at the same times each day. For example, at 8 am and 8 pm each day.
- Your dose may be adjusted over the first few weeks depending on the results of some blood tests. This allows your doctor to make sure that you have the dose that helps your condition and avoids any unwanted symptoms. Your doctor or pharmacist will explain to you the directions for taking your doses, and this information will also be printed on the label of the pack of tablets/capsules to remind you.
- If you have been given the Nuelin SA® brand of tablets, you should take your doses during a meal or just after a snack. For other brands of theophylline, it is not important whether you take your doses before or after food.
- If you have been given theophylline tablets (Nuelin SA® or Uniphyllin Continus®), you should swallow the tablets whole with a drink of water. Do not crush or chew the tablets.
- If you have been given theophylline capsules (Slo-Phyllin®), you can swallow the capsules whole with a drink of water, or you can open the capsule and sprinkle the contents on to a spoonful of soft food, such as yoghurt. This is particularly helpful if it is for a child. The yoghurt should then be swallowed whole without chewing the granules of medicine.
- If you forget to take a dose, leave out the missed dose and take the next dose at the normal time. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- Continue to take theophylline unless your doctor tells you otherwise. Bronchodilators like theophylline are usually prescribed long-term.
- Try to keep your regular appointments with your doctor. This is so your doctor can review your condition on a regular basis. Your doctor will want to test your blood from time to time to make sure that you are receiving the correct dose and also to check the levels of potassium in your blood.
- The amount of theophylline in your blood should be kept within a certain range. It can vary if you are unwell, or if you start or stop smoking, take other medicines, or drink more alcohol than usual. This is because these things interfere with the way theophylline is handled by your body. Some of these things will increase the amount of theophylline in your body, leading to side-effects. Others will reduce it, leading to your treatment not being as effective as it should be.
- If at any time you find that your symptoms are getting worse, contact a doctor or nurse for advice straightaway.
- If you want to buy any medicines, check with a pharmacist that they are safe for you to take. Some medicines (including the herbal remedy St John's wort) can affect the levels of theophylline in your blood and should not be taken alongside it without your doctor knowing.
- Some vaccines, such as the flu vaccine, may also affect theophylline levels. Make sure you tell your doctor about any vaccinations you have.
- If you are due to have an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking, as some anaesthetics can interfere with theophylline.
- Theophylline can be very toxic in overdose. If you suspect that someone has taken more than they should (and especially if it is a child), go to the accident and emergency department of your local hospital straightaway. Take the container with you, even if it is empty.
Can theophylline cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with theophylline. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.
|Common theophylline side-effects||What can I do if I experience this?|
|Feeling sick (nausea), upset stomach||Stick to simple foods - avoid rich or spicy meals. Try taking your doses after meals|
|A fast heartbeat, difficulty sleeping, feeling shaky or dizzy, being sick (vomiting)||If these symptoms continue or are severe, speak with your doctor or pharmacist, as they could be signs your dose is too high|
|Headache||Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headaches continue, let your doctor know|
If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.
How to store theophylline
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty, so the doctor knows what has been taken.
This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
Further reading and references
Manufacturer's PIL, Slo-Phyllin® Capsules; Merck Serono Ltd, The electronic Medicines Compendium. Dated April 2018.
Manufacturer's PIL, Uniphyllin Continus® Tablets; Napp Pharmaceuticals, The electronic Medicines Compendium. Dated October 2013.
British National Formulary, 78th Edition (Sep 2019); British Medical Association and Royal Pharmaceutical Society of Great Britain, London.