Canasa treats ulcerative proctitis. Try to empty your bowel and bladder just before using Canasa. It may be best to use this medicine at bedtime.

Canasa Overview


Canasa is a prescription medication used to treat ulcerative proctitis. Canasa helps relieve the symptoms of ulcerative proctitis (swelling in the rectum). Canasa belongs to a group of drugs called aminosalicylates. These work by stopping the body from producing a certain substance that may cause pain or inflammation.

Canasa comes in a rectal suppository. It is usually instilled once a day at bedtime.

Common side effects of Canasa include rectal pain and fever. It can also cause dizziness. Do not drive until you know how it affects you. 

Patient Ratings for Canasa

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What are you taking Canasa for?

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  • Other
  • Colitis, Ulcerative
  • Proctitis
  • Sigmoid Diseases

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  • A couple weeks
  • A month or so
  • A few months
  • A year or so
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Canasa Cautionary Labels


Uses of Canasa

Canasa is a prescription medication used to treat ulcerative proctitis (swelling in the rectum). 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.




Canasa Drug Class

Canasa is part of the drug class:

Side Effects of Canasa

Serious side effects have been reported with Canasa. See “Canasa Precautions” section.

Common side effects of Canasa include:

  • dizziness
  • rectal pain
  • fever
  • rash
  • acne
  • colitis

This is not a complete list of Canasa side effects. Ask your doctor or pharmacist for more information.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Canasa Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements.

No investigations of interaction between Canasa and other drugs have been performed. However, the following interactions between mesalamine medications and other drugs have been reported:

  • medicines that can damage the kidneys, including non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil) and aspirin (Ecotrin)
  • azathioprine (Imuran)
  • 6-mercaptopurine (Purinethol)
  • antacids such as Maalox, Mylanta, Mag-Ox, Caltrate, Tums, or Rolaids

Ask your doctor or pharmacist for more information.


Canasa Precautions

Serious side effects have been reported with Canasa including:

  • Kidney problems. Tell your doctor if you take non-steroidal anti-inflammatory drugs or have kidney disease. Your doctor will check your kidney function with a simple blood test before you start using Canasa.
  • Mesalamine may worsen ulcerative colitis. Tell your doctor if you experience the following symptoms:
    • cramping
    • acute abdominal pain
    • bloody diarrhea
    • fever
    • headache
    • rash
  • Hypersensitivity reaction. An allergic reaction is possible with Canasa. Tell your doctor if you are allergic to sulfasalazine (Azulfidine) or Canasa. Serious reactions can lead to heart problems, like myocarditis or pericarditis.
  • Liver failure is possible with Canasa. Tell your doctor if you have liver disease.
  • Upper GI tract obstruction. Pyloric stenosis or an obstruction in the digestive tract could prevent Canasa from reaching the colon and treating ulcerative colitis.
  • Pericarditis (inflammation of the lining around the heart). Tell your doctor if you experience symptoms of pericarditis including chest pain, rapid heartbeat, difficulty breathing, and fever. Your doctor may want to temporarily stop use of Canasa.

Do not use Canasa if you:

  • have kidney disease
  • are allergic to mesalamine or any ingredients in Canasa
  • are allergic to salicylates (including aspirin)

Canasa Food Interactions

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of mesalamine, there are no specific foods that you must exclude from your diet when receiving this medication.


Inform MD

Before using Canasa, tell your doctor about all your medical conditions. Especially tell your doctor if you:

  • have had an allergic reaction to sulfasalazine (Azulfidine), salicylates (such as aspirin), or Canasa
  • are taking nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil) and aspirin (Ecotrin) or other drugs that affect the kidneys
  • are taking azathioprine (Imuran) or 6-mercaptopurine (Purinethol)
  • have cramping, abdominal pain, bloody diarrhea, fevers, headaches, or rashes
  • have a history of myocarditis or pericarditis
  • have had inflamed pancreas (pancreatitis)
  • are allergic to other things, such as foods, preservatives, or dyes
  • have kidney, liver, or heart disease
  • have a history of stomach blockage
  • repeatedly see intact, partially intact, and/or capsule shells in the stool
  • are pregnant or breastfeeding

Tell your doctor about all the medicines you take including prescription and non-prescriptions medicines, vitamins, and herbal supplements.

Canasa and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.  

The FDA categorizes medications based on safety for use during pregnancy. Five categories – A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Canasa falls into category B. Studies in animals have failed to demonstrate a risk to the unborn baby and there are no well-controlled studies in pregnant women.

Canasa and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed.

The active ingredient in Canasa is excreted in human breast milk. The effect of Canasa on the nursing infant is not known.


Canasa Usage

Use Canasa exactly as prescribed. Do not change the dose or stop using Canasa without talking to your doctor.

  • Canasa rectal suppositories is instilled once a day at bedtime.
    • For best results, empty your rectum (have a bowel movement) just before using the suppository.
    • Detach one suppository from the strip of suppositories.
    • Hold the suppository upright and carefully peel open the plastic at the pre-cut line to take out the suppository.
    • Insert the suppository with the pointed end first completely into your rectum, using gentle pressure.
    • For best results, keep the suppository in your rectum for 3 hours or longer, if possible.
    • If you have trouble inserting the suppository, you may put a little bit of lubricating gel on the suppository.
    • Do not handle the suppository too much, since it may begin to melt from the heat from your hands and body.

Canasa Dosage

Use this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

  • Canasa (mesalamine suppository)
    • The dosage is one 1000 mg rectal suppository once daily at bedtime.

Canasa Overdose

If you take too much this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.


Other Requirements

  • Store Canasa below 25°C (77°F), may be refrigerated. Keep away from direct heat, light or humidity.
  • Rectal suppositories: these can cause stains on things it touches. Therefore keep it away from clothing and other fabrics, flooring, painted surfaces, marble, granite, plastics, andenamel. Be careful since the suppository may stain clothing.
  • Keep this and all medicines out of the reach of children.