If you have a certain kind of ulcerative colitis, your doctor might suggest Canasa as a treatment option for you.

Canasa is a prescription medication that’s used to treat mild to moderate ulcerative proctitis in adults. It comes as a suppository that you take rectally.

Canasa contains the active ingredient mesalamine. An active ingredient is what makes a drug work. Mesalamine belongs to a group of drugs called aminosalicylates.

This article describes the dosage of Canasa, as well as its strength and how to take the drug. To learn more about Canasa, see this in-depth article.

Note: This article covers Canasa’s usual dosage, which is provided by the drug’s manufacturer. But when using Canasa, always take the dosage that your doctor prescribes.

This section describes common dosage information for Canasa. Before you start taking this medication, your doctor will discuss Canasa dosing instructions specific to your condition.

What is Canasa’s form?

Canasa comes as a suppository that you take rectally (insert into your rectum).

What strength does Canasa come in?

Canasa suppositories are available in one strength: 1,000 milligrams (mg).

What are the usual dosages of Canasa?

The information below describes dosages that are commonly used or recommended. But be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.

For treating mild to moderate ulcerative proctitis, the recommended Canasa suppository dosage is 1,000 mg once per day. Your doctor will likely advise you to take this drug at bedtime.

Is Canasa used long term?

It’s not known whether Canasa is safe to use for more than 6 weeks.

Canasa is usually taken for 3 to 6 weeks based on how well it’s working to relieve symptoms. Your doctor will let you know how long you should take Canasa.

Canasa comes as a suppository that you take rectally once per day at bedtime. You’ll do this for 3 to 6 weeks or as long as your doctor advises.

You should not cut or break the suppository before you insert it into your rectum.

After you insert the suppository, try to keep it in your rectum for 1 to 3 hours, or longer if you’re able.

Your doctor may advise that you drink plenty of fluids while taking Canasa.

For information on Canasa expiration, storage, and disposal, see this article.

Accessible drug containers and labels

If you find it hard to read the prescription label on your medication, tell your doctor or pharmacist. Some pharmacies may provide medication labels that:

  • have large print or use braille
  • feature a code that you can scan with a smartphone to change the text to audio

Your doctor or pharmacist may be able to recommend pharmacies that offer these accessibility features if your current pharmacy doesn’t.

If you miss a dose of Canasa, take a dose as soon as you remember. Skip the missed dose if it’s almost time for your next dose. Then take the next dose at the regular time. Avoid taking two suppositories to make up for a missed dose.

If you need help remembering to take your dose of Canasa on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Do not use more Canasa than your doctor prescribes. Using more than this can lead to serious side effects.

Symptoms of overdose

Symptoms caused by a Canasa overdose can include:

What to do in case you take too much Canasa

Call your doctor right away if you think you’ve taken too much Canasa. You can also call 800-222-1222 to reach the American Association of Poison Control Centers or use its online resource. But if you have severe symptoms, call 911 (or your local emergency number) immediately or go to the nearest emergency room.

The sections above describe the usual dosage of Canasa provided by the drug’s manufacturer. If your doctor recommends Canasa for you, they will prescribe the dosage that’s right for you.

Remember, you should not change your dosage of Canasa without your doctor’s recommendation. Only take Canasa exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage.

Here are a few questions you may want to ask your doctor:

  • Does my dosage of Canasa need to change if I’m taking other medications along with it?
  • What should I do if I can’t retain the Canasa suppository for the recommended time?
  • How long will I need to take Canasa for my condition?

For information about the possible side effects of Canasa, see this article.

For support and advice from others living with an inflammatory bowel disease (IBD) such as ulcerative proctitis, join the Bezzy IBD community. To get news on treatments and tips for managing your condition, sign up for Healthline’s IBD newsletter.


Would my doctor need to adjust my Canasa dosage if I have kidney problems?



Not necessarily. The manufacturer doesn’t recommend a Canasa dosage adjustment based on how your kidneys work. But having kidney problems may increase your risk of having side effects from Canasa.

Before you start Canasa treatment, your doctor will check how well your kidneys work. This will help them determine whether Canasa is safe for you to use. While you’re taking Canasa, your doctor will monitor your kidney function closely.

Always talk with your doctor if you have any questions about your Canasa dosage.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.