Taking medicines

Last reviewed: April 2023

Next review date: April 2026

pills in a hand

If you have Crohn’s or Colitis, you may be prescribed medicine as part of your treatment.
This information is for anyone who wants to know more about medicines used to treat
Crohn’s and Colitis.

It looks at:

  • Medicines used to treat Crohn's and Colitis
  • Things to consider when deciding which medicine to take
  • Why some medicines have more than one name
  • What to do if you want to change or stop taking your medicine

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  • Key facts about taking medicines
    • Medicines are used to treat Crohn’s and Colitis symptoms. They can help prevent your condition from getting worse or causing complications.
    • It is important that you have all the information you need to make an informed choice before you decide to take a medicine.
    • Some people with Crohn’s or Colitis use more than one medicine at a time to manage their condition. This is known as combination therapy.
    • Some of the medicines prescribed for Crohn’s and Colitis come in several different forms. This is so that they can be taken in the way that helps them to work most effectively.
    • Let your IBD team know if you get any side effects or are struggling to take your medicine. It might take some time to find the right medicine for you.
  • Why are medicines used in Crohn’s and Colitis?

    Right now, there is no cure for Crohn’s or Colitis. But medicines can keep you feeling well for a long time.

    Medicines can be very effective in treating your symptoms. They can help to prevent your condition from getting worse or causing complications.

    At first, you may have medicines to reduce the inflammation in your gut and get your Crohn’s or Colitis under control. This is called induction therapy. When your Crohn’s or Colitis is under control, you will have maintenance therapy to keep it under control. Maintenance therapy is usually taken for a long time.

    Medicines do not work the same way for everyone. It is not always possible for your doctor to predict which treatment will suit you best. It is important to make sure you find a medicine that works for you. It may take some time to find the right medicine for you.

    For more information about the medicines used to treat Crohn’s and Colitis, see our treatments page.

    One thing I have learned is that if a type of medicine does not work, try not to stress. There are so many options out there, it may just take some time to find the right one for you.


    Living with Colitis

  • Where to find information about medicines

    All medicines come with a patient information leaflet. These are produced by the manufacturer of each medicine and approved by the MHRA. They include instructions on how to take the medicine and information on possible side effects. Copies of patient information leaflets can be found on the electronic medicines compendium website.

    The Association of the British Pharmaceutical Industry has details of companies that make prescription medicines. For companies that make over-the-counter medicines, visit the Proprietary Association of Great Britain website.

  • Taking more than one medicine (combination therapy)

    Many people with Crohn’s or Colitis use more than one medicine at a time to manage their condition. This is called combination therapy.

    Combination therapy is sometimes given for a short time to help control a flare-up. For example, you might be prescribed steroids together with 5-ASAs or an immunosuppressant such as azathioprine.

    Combination therapy can also be taken for a long time. There is evidence that taking certain medicines together can be more effective than taking them alone. A common combination therapy used is a biologic, such as infliximab, along with an immunosuppressant (azathioprine, mercaptopurine or methotrexate).

    Combining some medicines may make them more effective. But, taking more than one medicine can also increase the risk of side effects. It is important to discuss the risks and benefits of combination therapy with your IBD team and decide on the right treatment for you.

  • Deciding which medicine to take

    Your IBD team might give you a choice of different medicines to treat your Crohn’s or Colitis. Before deciding to take any medicine, it is important that you have all the information you need to make an informed choice.

    Our appointment guide has some questions you might want to ask your IBD team about the medicines being offered. It also has space to write down some questions of your own.

    You may want to ask about:

    • What the medicine is and why it is being offered to you
    • The possible benefits and risks, including side effects
    • Which form the medicine comes in and if you can choose which form you prefer
    • How frequently it should be taken
    • If it needs to be taken at a certain time of day
    • How to store the medicine safely
    • How long you need to take the medicine for
    • How to safely stop taking it
    • How long it usually takes to start working
    • Whether the medicine contains any ingredients you are allergic to

    If you are pregnant, breastfeeding or trying to conceive, it is also important you discuss this with your IBD team. Some medicines may not be suitable for you.

    For more details see our information on pregnancy and breastfeeding and reproductive health.

    Medicine Tool

    Use this tool to understand more about potential treatment options that suit your needs. The tool is designed to help you:

    • Understand the differences between types of medicines
    • Explore different treatment options based on your personal preferences
    • Feel empowered to discuss medicine options with your IBD team
  • Why do some medicines have several names?

    Many medicines have different names:

    • The generic name is the name of the active ingredient in the medicine
    • The brand name is created by the company that makes the medicine


    Every medicine has an approved generic or medical name, named after the active ingredient of the medicine. Many medicines are also known by a brand or trade name, chosen by the pharmaceutical company making and selling the medicine.

    Read more about brand names versus generics on the NHS website.

    For example, the medicine adalimumab (generic name) is also known as Humira (brand name). Some medicines are sold in a generic form as well as in a branded form. If several companies make and sell the same medicine, it will have several different brand names. For example, different brand names for mesalazine include

    • Asacol
    • Zintasa
    • Octasa
    • Pentasa
    • Salofalk
    • Mezavant

    Does it matter which medicine I have?

    Medicines usually contain active and inactive ingredients. The active ingredient is the generic medicine. The inactive ingredients help to make the medicine into its tablet, cream or liquid form. They can also be used to give tablets a particular colour or affect how long the tablets take to dissolve in the gut. The inactive ingredients can be slightly different in each brand’s version of the medicine. Your medicine should have the same effect as long as your dose contains the same amount of active ingredient.

    For most medicines, these small differences are unlikely to create any problems. For a small number of medicines, the differences in formulation may mean one brand will suit you better than others. For example, some of the different brands of mesalazine come in formulations that target different parts of the gut. For this reason, your doctor may decide to prescribe a particular brand rather than the generic version.


    A biosimilar is a medicine which is very similar to the original biologic medicine. The first brand to produce a certain biologic medicine is known as the “originator.” Other brands of the same medicine are known as “biosimilars.”

    Biologic medicines are made using living cells. The process to make biologics is complicated. Each manufacturer has its own unique process and cells to make the medicine. The medicines made can never be exactly identical because they are made using different cells. So, we have biosimilars, which are similar but not identical to the original biologic medicine.


    Example of biosimilars - infliximab

    Remicade was the first brand of infliximab, so it is the originator. Flixabi, Inflectra, Remsima and Zessly are biosimilars of Remicade but work in the same way. They are very similar to Remicade with the same treatment effects. 


    For a biosimilar to be approved for use, it has to meet strict standards to show it is as safe and effective as the original biologic medicine.

    For more information on biosimilars see our information on biologic medicines.

  • Why do medicines come in different forms?

    Some of the medicines prescribed for Crohn’s and Colitis come in several different forms. This is so that they can be taken in the way that helps them to work most effectively. This is usually by mouth (oral), but they may be applied directly to the body (topical) or taken by infusion or injection.

    Oral medicines

    Many medicines used to treat Crohn’s and Colitis come in a tablet, capsule or granule form. These can be swallowed by mouth. Anything taken by mouth will start to dissolve very quickly. Many of the tablets and capsules have a special ‘gastro-resistant’ coating. This helps stop the tablet from being broken down by the acid in your stomach. It makes sure the medicine is released in the right part of your gut– usually the small bowel or colon.

    Some tablets and capsules should be swallowed whole and not broken or crushed. Some medicines need to be taken before or with food. Your IBD team or pharmacist will let you know how your medicine should be taken. Details can also be found on the information leaflet that comes with your medicine.

    Topical treatment

    Topical treatments are applied directly to the affected part of the body.

    Topical treatment is usually recommended if the inflammation is in the lower part of the colon or rectum. Steroids and aminosalicylates (5-ASAs) are sometimes given topically, using a suppository or enema.


    One way of delivering topical treatment to inflammation in these areas is to use a suppository. This is a small bullet-shaped capsule of medicine. It is usually covered in a waxy substance that will dissolve at body temperature. Follow the instructions on the leaflet inside your medicine packet. Suppositories are inserted directly into your bottom (anus). As it dissolves, it releases the medicine in the right area.


    Another way of getting a medicine directly into the rectum and colon is to take it as an enema. These can come as a liquid or a rectal foam. Enemas and rectal foams are put into the rectum through your bottom (anus) using an applicator. Rectal foams and enemas work better when you keep the liquid or foam inside your bottom for as long as possible. Follow the instructions on the leaflet that comes with your medicine. It will have instructions on how to use the rectal foam or enema.

    Some people may find using suppositories and enemas slightly uncomfortable and they can take a while to get used to. If you are struggling to use suppositories or enemas, speak to your IBD team.

    Ointments and creams

    If the inflammation is on the surface of the skin, an ointment or cream may be helpful. Tacrolimus is a medicine available in ointment form and may be used to treat perianal Crohn’s.

    Injections and infusions

    Some medicines have to be given by injection or infusion because they may be poorly absorbed or ineffective if taken by mouth (orally). Injections usually come as pre-filled syringes or pens.

    There are different types of injections:

    • Subcutaneous: an injection given under the skin, usually in your thigh or stomach.
    • Intramuscular: an injection given into a muscle.
    • Intravenous (IV): into a vein. Intravenous infusions are given through a drip into a vein, usually in your arm. You go to a hospital or clinic to have it.

    If you are having injections, you will usually need to have an infusion at the hospital for your first dose. This is followed by injections given at home. Your doctor or nurse can teach you how to inject yourself at home. Or they could teach a family member or friend to do it for you.

    Steroids may be given by infusion to get a quick response if you are having a severe flare-up.

  • Can other medicines affect Crohn’s and Colitis medicines?

    It is possible that other medicines might interact with your Crohn’s or Colitis medicine. This could make your treatment less effective, or change the side effects you get. Read our individual medicine information or the patient information leaflet that came with your medicine to see if there are any interactions with your medicine. You can also find copies of patient information leaflets on the electronic medicines compendium website.


    It is very important to tell your doctor and IBD team about any other medicines, treatments or therapies you are taking. This includes

    • Medicines for other conditions
    • Over-the-counter medicines such as cold and flu tablets
    • Complementary or alternative medicines, including herbal medicines. Always let your doctor or IBD team know if you are planning to take herbal medicines. They may interact with the medicines used to treat your Crohn’s or Colitis. Read more about complementary and alternative medicine on the NHS website.


    It is a good idea to take a list of all your medicines, including dosages, to your appointments. Our appointment guide has space to note down what medicines you are taking or have tried before.

  • Does it matter if I do not take my medicine?

    It can be hard to get into a routine of remembering to take your medicines every day. At first, when your medicine has an immediate effect on your symptoms, you may find it easy to remember to take your doses exactly as instructed. However, once you feel better and your condition is on your mind less, you may be less focused on taking your medicine and may forget a dose.

    You may be tempted to stop taking your medicine altogether, thinking you do not need it now that your symptoms are improving. A lot of people get fed up with having to take medicine every day, maybe even several times a day. These are understandable feelings. However, continuing to take your medicine, even when you feel well (maintenance therapy) can reduce the risk of having a flare-up. Sticking to your treatment plan can help keep your symptoms under control.

    Let your IBD team know if you are struggling to take your medicine. They may be able to offer an alternative. This could be taking medicine in a different form, or taking a more convenient dose that fits better with your daily life.

    Always talk to your IBD team if you are thinking about stopping or reducing treatment. Some medicines, such as steroids, will need to be reduced gradually.

    If you do miss taking a dose, the patient information leaflet that comes with your medicine should tell you what to do. If you are unsure, check with your IBD team.

    If you are having trouble remembering to take your medicine each day, try setting an alarm or using a reminder app.

    I would encourage anyone to be honest with your team if a new medicine does not feel right. They are there to help you and will want to find the best option for you.

    Living with Colitis 

  • Can I change the dose of my medicine?

    If you have Ulcerative Colitis, and are experiencing a flare-up, you may be able to temporarily increase the dose of 5-ASAs you take. If you decide to do this, it is important to let your IBD team know as soon as possible. Find out more in our flare-ups information.


    It might take some time to find a medicine dose that works for you. It is important that you do not stop taking any prescribed medicines without discussing it with your IBD team, even if your symptoms improve. It is also important to take the full dose you have been prescribed.

    Some medicines need to be taken in a certain way – for example, at particular times of day, on an empty stomach, or with or after food. If your lifestyle or daily routine makes it difficult for you to do this, let your IBD team know. Depending on which medicine you take, your IBD team may be able to change your dose to something that works better for you. This might be by:

    • Simplifying your dose so you only need to take your medicine once a day
    • Changing the form of your medicine, such as changing from infusions to injections.
  • How safe are Crohn's and Colitis medicines?

    Before new medicines are used in the UK, they go through strict research and clinical trials on thousands of people. This process can take many years. Read about how we talk about the effectiveness of medicines for more information on clinical trials.

    In the UK, medicines and medical devices are licensed by the Medicines and Healthcare Products Regulatory Agency (MHRA).

    The MHRA makes sure all medicines are effective and meet strict safety standards. The MHRA demands very high standards from medicines manufacturers. It will only issue a licence when it is satisfied that a medicine meets all its safety and quality requirements. Visit the MHRA website for more information about the work that it does.

  • Side effects

    All medicines are made and prescribed to help you get benefits, such as reducing your symptoms and preventing flare-ups. All medicines can also cause unwanted effects called side effects, but not everyone gets them. It is important to understand the possible side effects of your medicine. These may be mild and go away once your body has adjusted to the medicine. Or they may be more severe and mean you have to stop taking the medicine and need further treatment.

    I find it useful to keep an ongoing record of any side effects and the frequency that they occur so I can discuss them clearly and accurately with my IBD team later.

    Living with Colitis 

    It is worth talking to your doctor or IBD team about any worries you have about side effects or the amount of medicine you are taking. They may be able to reassure you or suggest changes that you will find helpful. Sometimes a change in brand or form of medicine would suit you better and reduce side effects.

    You can find out more about the side effects for medicines used to treat Crohn’s and Colitis in our medicine information.

    We encourage you to report any side effects to the Medicines and Healthcare Products Regulatory Agency (MHRA). You can do this through the Yellow Card scheme online or by downloading the MHRA Yellow Card app. This helps collect important safety information about medicines.

  • Special precautions

    Taking certain medicines used to treat Crohn’s and Colitis may mean you need to take extra care in your daily life. For example, medicines that affect the immune system can make it harder for your body to fight off infections. If you are not sure whether your medicine affects your immune system, read our medicine information or ask your IBD team.


    You should avoid live vaccines if you are taking a medicine that weakens your immune system. If you are not sure if this includes you, read the “vaccinations” section in the relevant medicine information or ask your IBD team.

    You can have non-live vaccines such as the flu, pneumococcal and COVID-19 vaccines.

    Live vaccines used in the UK include:

    • TB vaccine
    • Shingles vaccine – but a non-live version is also available
    • Chickenpox vaccine
    • Measles, mumps and rubella vaccines
    • Nasal flu vaccine used in children – but the injected flu vaccine used in adults is not live
    • Rotavirus vaccine
    • Yellow fever vaccine
    • Oral typhoid vaccine – but the injected typhoid vaccine is not live

    If someone that you live with is due to have a live vaccine

    Live vaccines contain weakened strains of virus or bacteria. There is a small risk that people who have received live vaccines could spread (transmit) the weakened form of the virus to close contacts who are immunosuppressed and cause an infection. Most of the live vaccine viruses used in the UK do not transmit to contacts or can be minimised by following simple precautions such as:

    • Careful hand washing before direct contact with the person who has had the vaccine, and before preparing food.
    • Covering any rashes until the rash is dry and crusted.

    Sun safety

    Some medicines used to treat Crohn’s and Colitis can increase how sensitive your skin is to sunlight. In some cases, they can increase your risk of developing skin cancers.

    Find out more in the “special precautions” section in our individual medicines information.

    You can protect your skin from the sun by using sunscreen, covering your skin and wearing a hat when you are out in the sun. You should avoid using sun beds. The NHS has more information on sun safety.

    The patient information leaflet that comes with your medicine will also tell you whether you need to take any special precautions.

  • Travelling with medicines

    If you are travelling overseas, make sure you take enough medicine for your whole trip, plus extra in case of delays. Some places have restrictions on what medicines you are allowed to bring into the country. Check with the embassy of the country you are visiting before you travel. Keep your medicines in their original packaging, along with the patient information leaflet. You might also need a copy of your prescription and a covering letter from your doctor.

    When you are travelling, it is important to be aware of the temperature your medicines need to be stored at. Copies of patient information leaflets can be found on the electronic medicines compendium website.

    Our information on travelling with Crohn’s or Colitis has more details on transporting and storing your medicines while travelling.

  • Who can I talk to about my treatment?

    Find an IBD nurse specialist

    Many hospitals have an IBD nurse specialist for information and support. Check our online map to find an IBD nurse specialist in your area.

    It can be very helpful to build a good relationship with your IBD team, so that you can ask about your options and discuss any concerns and worries. Talking about your feelings and symptoms will help them understand your needs and what is or is not working well for you. Our appointment guide can help you note down how you are feeling, and any questions you might have for your IBD team at your next appointment.

    You can also talk to your GP or local pharmacist. Pharmacists can often answer any questions you have about medicines.

    I was diagnosed with Colitis when I was 15 and was anxious that my studies and social life would be affected. The nurses, doctors, and my parents were all incredibly supportive and always had a next step for me even when a medicine would not work the way we wanted it to. It is really important to not lose hope when medicines are not working. There will be a plan and the IBD team will keep trying options.

    Living with Colitis

  • Other organisations
  • About this information

    We follow strict processes to make sure our information is based on up-to-date evidence and easy to understand.

    Please email us at evidence@crohnsandcolitis.org.uk if:

    • You have any comments or suggestions for improvements
    • You would like more information about the sources of evidence we use
    • You would like details of any conflicts of interest

    You can also write to us at Crohn’s & Colitis UK, 1 Bishop Square, Hatfield, AL10 9NE, or contact us through our Helpline: 0300 222 5700


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We know it can be difficult to live with, or support someone living with these conditions. But you’re not alone. We provide up-to-date, evidence-based information and can support you to live well with Crohn’s or Colitis.

Our helpline team can help by:

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