Canasa (mesalamine) is a brand-name prescription medication. The Food and Drug Administration (FDA) has approved it to treat ulcerative proctitis in adults.

Canasa comes as a suppository that’s inserted rectally. It belongs to a class of drugs called aminosalicylates. And it’s available in a generic form called mesalamine.

For information about the dosage of Canasa, including its strength and how to take it, keep reading. For a comprehensive look at Canasa, see this article.

This article describes typical dosages of Canasa provided by the drug’s manufacturer. When taking Canasa, always follow the dosage prescribed by your doctor.

Talk with your doctor about the best dosage of Canasa for you.

Canasa form

Canasa comes as a suppository that’s inserted rectally.

Canasa strength

Canasa comes in one strength: 1,000 milligrams (mg).

Typical dosages

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for ulcerative proctitis

The recommended dosage of Canasa to treat ulcerative proctitis is 1,000 mg inserted rectally once per day at bedtime. You will typically take this medication for a period of 3 to 6 weeks to treat your condition.

Long-term treatment

Typically, you’ll only take Canasa for a short time. This medication hasn’t been studied in people taking it for longer than 6 weeks. So, in most cases, your doctor will only recommend taking Canasa for a period of 3 to 6 weeks.

Talk with your doctor about the best treatment plan for you and how long you should take Canasa.

Canasa comes as a suppository that’s inserted rectally. You should take your dose of Canasa at bedtime for 3 to 6 weeks, as directed by your doctor.

Be sure to insert the whole Canasa suppository. Do not break it apart. You should try to retain the suppository for at least 1 to 3 hours after inserting it.

It’s important to note that Canasa suppositories can stain some surfaces, including clothing and other materials such as flooring or granite. So be careful what surfaces you allow Canasa suppositories to touch, since they may stain.

If you’d like step-by-step instructions on how to use Canasa, see the manufacturer’s website.


If you’re having trouble reading your prescription label, talk with your doctor or pharmacist. Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you’re having trouble opening medication bottles, ask your pharmacist about putting Canasa in an easy-open container. They also may recommend tools that can make it easier to open bottles.

If you miss your dose of Canasa, you should take it as soon as possible. However, if it’s almost time for your next dose, skip the dose that you missed and continue with your regular schedule. Do not take two doses of Canasa at once to make up for a missed dose.

To help make sure that you don’t miss a dose, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.

If you use more Canasa than your doctor prescribes, you may develop serious side effects.

It’s important that you do not use more Canasa than your doctor advises.

Symptoms of an overdose

Overdose symptoms of Canasa can include:

If you take more than the recommended amount of Canasa

Call your doctor right away if you believe you’ve taken too much Canasa. Another option is to call the American Association of Poison Control Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

The dosages in this article are typical dosages provided by the drug’s manufacturer. If your doctor recommends Canasa for you, they will prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes for you.

As with any drug, never change your dosage of Canasa without your doctor’s recommendation. If you have questions about the dosage of Canasa that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Canasa. These additional articles might be helpful to you:

Disclaimer: Medical News Today 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.