Examples: Imuran®, Azathioprine (generic)
Azathioprine is part of a group of medicines called immunosuppressants. They work by reducing the inflammatory action of your disease. In order for it to work well, this medicine should be taken regularly.
Azathioprine should be taken on an empty stomach, either one hour before or three hours after meals. The amount you will need to take will depend on your weight and the activity of your disease, and it is usually given daily, sometimes in divided doses. It may take weeks or months for your condition to improve, therefore do not be discouraged if results are not immediate. Please note that azathioprine does not help everyone who takes it.
Due to the potential risk of the drug interacting with other medicines, you should inform your doctor and/or pharmacist about any medication you are currently taking, or any new medicines you have been prescribed.
This includes any medications bought from the pharmacy without a prescription as well as herbal and complementary medicines (e.g St. John’s Wort). To ensure you remember everything, it may be helpful to bring a list of current medications with you when you see the doctor, nurse or pharmacist. You should also inform us if you are allergic to the substance 6- mercaptopurine or any other medication.
Before starting azathioprine, you must inform your doctor if you have/had any kidney problems, liver problems or severe bone marrow disease. We also need to be aware if you have Lesch – Nyhan syndrome, TPMT deficiency or an inflamed pancreas. You should also inform us if you have an uncontrolled infection or a tendency to catch infections easily.
Due to a potential risk to the foetus, both men and women of child bearing potential should use effective contraception whilst on azathioprine and for three months after stopping the drug. Azathioprine may interfere with the effectiveness of intrauterine contraceptive devices (IUCDs), so extra contraceptive measures are recommended. Please inform your doctor as soon as possible if you plan to become pregnant or think that you may be pregnant.
Azathioprine passes into breast milk, therefore please inform your doctor if you are breast-feeding and on treatment. You may be advised to stop breast-feeding while on treatment.
Your body’s resistance to infection can be reduced while you are taking azathioprine. Therefore you should avoid close contact with people who have viral infections, in particular chicken pox or shingles. If you develop either of these, you should inform your doctor immediately. You should also ask your doctor or pharmacist before having any vaccinations.
You may also be more at risk of catching infections of the skin, mouth, stomach and intestines, lungs and urinary tract. Please inform your doctor about any symptoms of infection which last for more than three days (for example, sore throat, cough, fever).
Cooked chilled foods should be reheated thoroughly, and salad washed well; avoid ready prepared supermarket salads. Do not eat soft cheese made from unpasteurized milk.
Azathioprine may also affect your performance of skilled tasks (e.g. driving). Avoid driving if you find you are affected.
Men and women are advised not to drink more than 14 units of alcohol per week, spread evenly over three or more days, on a regular basis. 14 units is equivalent to six pints of average strength beer or 10 small glasses of low-strength wine.
Take care to avoid too much sun (including sunbeds) whilst taking this medicine and use a sunscreen with a high protection factor e.g. SPF 50.
It is very important that you are regularly checked whilst using azathioprine. Therefore, before starting treatment an initial blood test will be carried out. A blood test is then usually needed every two weeks for six weeks, then monthly for three months and then at least every 12 weeks. This may vary depending on your condition. Your weight, blood pressure, cholesterol and blood sugar will also be checked regularly. It will be your responsibility to ensure that you attend regularly for your blood tests. It is important that you do not miss these and that you do not take azathioprine unless you are having blood tests regularly.
As with most medicines, azathioprine may cause side-effects, although this is not the case for everyone.
Possible side-effects include:
Sudden worsening of general health, such as:
Please refer to the leaflet included with the medicine for further information, or contact the pharmacy department on: 020 7566 2362
Author: Edward Hindle, advanced specialist pharmacist (OITS)
Revision number: 2
Approval date: July 2018
Review date: July 2021