Canasa - General Information

An anti-inflammatory agent, structurally related to the salicylates, which is active in inflammatory bowel disease. It is considered to be the active moiety of sulphasalazine. (From Martindale, The Extra Pharmacopoeia, 30th ed)


Pharmacology of Canasa

Canasa (INN, BAN), also known as Mesalamine (USAN) or 5-aminosalicylic acid (5-ASA), is an anti-inflammatory drug used to treat inflammation of the digestive tract (Crohn's disease) and mild to moderate ulcerative colitis. Canasa is a bowel-specific aminosalicylate drug that is metabolized in the gut and has its predominant actions there, thereby having fewer systemic side effects. As a derivative of salicylic acid, 5-ASA is also an antioxidant that traps free radicals, which are potentially damaging by-products of metabolism.


Canasa for patients

CANASA® Rectal Suppositories (Mesalamine, USP) 500 and 1000 mg

Read this information carefully before you begin treatment. Also, read the information you get whenever you get more medicine. There may be new information. This information does not take the place of talking with your doctor about your medical condition or your treatment. If you have any questions about this medicine, ask your doctor or pharmacist.

What is CANASA®?

CANASA® (can-AH-sah) is a medicine used to treat ulcerative proctitis (ulcerative rectal colitis). CANASA® works inside your rectum (lower intesti ne) to help reduce bleeding, mucous and bloody diarrhea caused by inflammation (swelling and soreness) of the rectal area. You use CANASA® by inserting it into your rectum.

Who should not use CANASA®?

Do not use CANASA® if you are allergic to the active ingredient mesalamine (also found in drugs such as Rowasa, Asacol, Pentasa, Azulfidine, and Dipentum), if you are allergic to the inactive ingredients, or if you have had any unusual reaction to the ingredients.

Tell your doctor if you:

  • Have kidney problems. Using CANASA® may make them worse.
  • Have had inflamed pancreas (pancreatitis).
  • Are pregnant. You and your doctor will decide if you should use CANASA®.
  • Have ever had pericarditis (inflamed sac around your heart).
  • Are allergic to sulfasalazine. You may need to watch for signs of an allergic reaction to CANASA®.
  • Are allergic to aspirin.
  • Are allergic to other things, such as foods, preservatives, or dyes.

How should I use CANASA®?

Follow your doctor's instructions about how often to use CANASA® and how long to use it. For the 500 mg suppository, the usual dose is one suppository 2 times a day for 3-6 weeks. For the 1000 mg suppository, the usual dose is one suppository at bedtime for 3-6 weeks. We do not know if CANASA® will work for children or is safe for them.

Follow these steps to use CANASA®:

1. For best results, empty your rectum (have a bowel movement) just before using CANASA®.
2. Detach one CANASA® suppository from the strip of suppositories. 3. Hold the suppository upright and carefully peel open the plastic at the pre-cut line to take out the suppository.
4. Insert the suppository with the pointed end first completely into your rectum, using gentle pressure.
5. For best results, keep the suppository in your rectum for 3 hours or longer, if possible.

If you have trouble inserting CANASA®, 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.

If you miss a dose of CANASA®, use it as soon as possible, unless it is almost time for next dose. Do not use two CANASA®suppositories at the same time to make up for a missed dose.

Keep using CANASA® as long as your doctor tells you to use it, even if you feel better.

CANASA® can cause stains on things it touches. Therefore keep it away from clothing and other fabrics, flooring, painted surfaces, marble, granite, plastics, and enamel. Be careful since CANASA® may stain clothing.

What should I avoid while taking CANASA®?

Do not breast feed while using CANASA®. We do not know if CANASA® can pass through the milk and harm the baby. Tell your doctor if you become pregnant while using CANASA®.

What are the possible side effects of CANASA®?

  • The most common side effects of CANASA® are: headache, gas or flatulence, and diarrhea. These events also occurred when patients were given an inactive suppository.
  • Less common, but possibly serious side effects include a reaction to the medicine (acute intolerance syndrome) that includes cramps, sharp abdominal (stomach area) pain, bloody diarrhea, and sometimes fever, headache and rash. Stop use and tell your doctor right away if you get any of these symptoms.
  • In rare cases, the sac around the heart may become inflamed (pericarditis). Tell your doctor right away if you develop chest pain or shortness of breath, which are signs of this problem.
  • In rare cases, patients using CANASA® develop worsening colitis (pancolitis).
  • A very few patients using CANASA® may have mild hair loss.
  • Other side effects not listed above may also occur in some patients.

If you notice any other side effects, check with your doctor or pharmacist.

How should I store CANASA®?

Store CANASA® below 25 °C (77 °F), do not freeze it. Keep it away from direct heat, light, or humidity. Keep it out of the reach of children.

General advice about prescription medicines

Medicines are sometimes prescribed for conditions that are not mentioned in patient information leaflets. Do not use CANASA® for a condition for which it was not prescribed. Do not give CANASA® to other people, even if they have the same symptoms you have.

This leaflet summarizes the most important information about CANASA®. If you would like more information, talk with your doctor. You can ask your pharmacist or doctor for information about CANASA® that is written for health professionals.


Canasa Interactions

No information provided.


Canasa Contraindications

CANASA® 500 mg and 1000 mg Suppositories are contraindicated in patients who have demonstrated hypersensitivity to mesalamine (5-aminosalicylic acid) or to the suppository vehicle [saturated vegetable fatty acid esters (Hard Fat, NF)], or to salicylates (including aspirin).


Additional information about Canasa

Canasa Indication: For the treatment of active ulcerative proctitis.
Mechanism Of Action: Although the mechanism of action of mesalazine is not fully understood, it appears to be topical rather than systemic. Mucosal production of arachidonic acid metabolites, both through the cyclooxygenase pathways, i.e., prostanoids, and through the lipoxygenase pathways, i.e., leukotrienes and hydroxyeicosatetraenoic acids, is increased in patients with chronic inflammatory bowel disease, and it is possible that mesalamine diminishes inflammation by blocking cyclooxygenase and inhibiting prostaglandin production in the colon.
Drug Interactions: Azathioprine The 5-ASA derivative increases the toxicity of thiopurine
Mercaptopurine The 5-ASA derivative increases the toxicity of thiopurine
Thioguanine The 5-ASA derivative increases the toxicity of thiopurine
Food Interactions: Not Available
Generic Name: Mesalazine
Synonyms: 5-aminosalicylate; 5-aminosalicylic acid; 5-ASA; Mesalamine
Drug Category: Anti-Inflammatory Agents, Non-Steroidal
Drug Type: Small Molecule; Approved

Other Brand Names containing Mesalazine: Asacol; Asacolitin; Canasa; Claversal; Fisalamine; Lixacol; Mesasal; Pentasa; Rowasa; Salofalk;
Absorption: 20 to 30% absorbed following oral administration. 10 to 35% absorbed from the colon (rectal suppository) - extent of absorption is determined by the length of time the drug is retained in the colon.
Toxicity (Overdose): Oral, mouse: LD50 = 3370 mg/kg; Oral, rat: LD50 = 2800 mg/kg; Skin, rabbit: LD50 = >5 gm/kg. There have been no documented reports of serious toxicity in man resulting from massive overdosing with mesalamine. Under ordinary circumstances, mesalamine absorption from the colon is limited.
Protein Binding: About 80% of N-Ac-5-ASA is bound to plasma proteins, whereas 40% of mesalamine is protein bound.
Biotransformation: Rapidly and extensively metabolized, mainly to N-acetyl-5-ASA (Ac-5-ASA) in the intestinal mucosal wall and the liver. Ac-5-ASA is further acetylated (deactivated) in at least 2 sites, the colonic epithelium and the liver.
Half Life: The mean elimination half-life was 5 hours for 5-ASA and six hours for N-acetyl-5-ASA following the initial dose. At steady state, the mean elimination half-life was seven hours for both 5-ASA and N-acetyl-5-ASA.
Dosage Forms of Canasa: Suspension Rectal
Tablet, extended release Oral
Tablet, delayed release Oral
Tablet, coated Oral
Suppository Rectal
Enema Rectal
Chemical IUPAC Name: 5-amino-2-hydroxybenzoic acid
Chemical Formula: C7H7NO3
Mesalazine on Wikipedia:
Organisms Affected: Humans and other mammals