Norphyllin SR prolonged release tablets contain the active ingredient aminophylline. Aminophylline is a mixture of a medicine called theophylline and a substance called ethylenediamine. The ethylenediamine makes the theophylline more soluble in water. The action of this medicine is actually due to the theophylline.
Theophylline is a type of medicine called a xanthine bronchodilator. It is used to open the airways. Theophylline works by causing the muscles surrounding the airways to relax, by a mechanism that is not fully understood. This allows the airways in the lungs to open.
In conditions where the airways tighten, such as asthma or chronic obstructive pulmonary disease (COPD, eg emphysema and chronic bronchitis) , it is difficult for air to get in and out of the lungs. By opening the airways, theophylline makes it easier to breathe.
Norphyllin SR tablets are designed to release the theophylline slowly over 12 hours. They are taken as a regular twice daily treatment to help keep the airways relaxed and open all the time. The tablets should be swallowed whole, as crushing or chewing them will stop the prolonged release action from working.
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.
Children must not take ephedrine (a decongestant found in some cough and cold remedies) while taking aminophylline.
The following medicines may increase the blood level of theophylline; your doctor may need to reduce your aminophylline dose if you take any of these in order to avoid side effects:
The following medicines may decrease the blood level of theophylline; your doctor may need to increase your aminophylline dose if you take any of these, in order to make sure it is effective:
Theophylline may decrease the blood levels of the following medicines, which may reduce their effects:
Aminophylline should not normally be taken with beta-blockers such as propranolol, as these can cause the airways to narrow, thus opposing the effects of theophylline.
There may be a risk of seizures if ketamine is taken with aminophylline.
Aminophylline may oppose the sedative effects of benzodiazepines, eg diazepam, clonazepam.
The level of thyroid hormones in the body affects the way the body handles theophylline. If you have high thyroid hormone levels and start treatment to lower them, eg with medicines such as carbimazole, propylthiouracil or radioactive iodine, your doctor may decrease your aminophylline dose. If you have low thyroid hormone levels and start treatment with thyroxine, your doctor may increase your aminophylline dose.
Aminophylline may potentially decrease the amount of potassium in the blood. If it is taken in combination with any of the following medicines, which can also lower potassium in the blood, the risk of a low blood potassium level (hypokalaemia) is increased:
A low blood potassium level can have serious effects, which is why people with severe asthma, who may be taking several of these medicines, should have their blood potassium level monitored regularly.
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Aminophylline injection is also available. It is used rarely to treat severe asthma attacks in hospital.