Canasa-Suppository (Mesalamine) , also known as 5-aminosalicylic acid is used to treat ulcerative proctitis, a type of bowel disease. It does not cure ulcerative proctitis, but it may decrease the number of stools, the amount of mucus/blood in the stools, and the rectal bleeding caused by irritation/swelling of the colon/rectum. Mesalamine is an aminosalicylate anti-inflammatory drug. It is believed to work by blocking the production of certain natural chemicals that may cause pain and swelling. Canasa affects a substance in the body that causes inflammation, tissue damage, and diarrhea. Canasa is used to treat ulcerative colitis, proctitis, and proctosigmoiditis. Rectal mesalamine is in a class of medications called anti-inflammatory agents. It works by stopping the body from producing a certain substance that may cause inflammation.It may also be used for purposes not listed in the medication guide.

Do not take a rectal suppository or enema by mouth. Use it only in your rectum. For best results, use Canasa at bedtime. Try to empty your bowel and bladder before using rectal medicine. Wash your hands before and after using rectal medicine. Remove the wrapper before inserting the suppository. Avoid handling the suppository too long or it will melt. Lie on your back with your knees up toward your chest. Gently insert the suppository into your rectum about 1 inch, pointed tip first. Stay lying down for a few minutes while the suppository melts. You should feel little or no discomfort. Avoid using the bathroom for at least an hour. Shake the rectal enema liquid well just before each use. To use the enema, lie on your left side with your left leg extended and your right leg slightly bent. Remove the cap from the applicator tip and gently insert the tip into your rectum. Slowly squeeze the bottle to empty the contents into the rectum. After using the enema, lie down on your left side for at least 30 minutes to allow the liquid to distribute throughout your intestines. Avoid using the bathroom, and hold in the enema at least 1 hour, or all night if possible.

• tell your doctor and pharmacist if you are allergic to mesalamine, salicylate pain relievers such as aspirin, choline magnesium trisalicylate, diflunisal, magnesium salicylate. Tell your doctor if you are allergic to sulfites (substances used as food preservatives and found naturally in some foods) or any foods, dyes, or preservatives. Ask your pharmacist for a list of the ingredients.

• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: aspirin and other nonsteroidal anti-inflammatory drugs tell your doctor if you have or have ever had myocarditis (swelling of the heart muscle), pericarditis (swelling of the sac around the heart), asthma, allergies, or liver or kidney disease.

• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding

• you should know that mesalamine may cause a serious reaction. Many of the symptoms of this reaction are similar to the symptoms of ulcerative colitis, so it may be difficult to tell if you are experiencing a reaction to the medication or a flare Call your doctor if you experience some or all of the following symptoms: stomach pain or cramping, bloody diarrhea, fever, headache, weakness, or rash.

Rectal mesalamine may cause side effects.

Tell your doctor if any of these symptoms are severe or do not go away:

• leg or joint pain, aching, tightness or stiffness

• heartburn

• dizziness

• hemorrhoids 

• acne

• pain in the rectum

• slight hair loss

Some side effects can be serious. If you experience any of the following symptoms or those listed in the SPECIAL PRECAUTIONS section, call your doctor immediately:

• chest pain

• shortness of breath

Mesalamine may cause other side effects. Call your doctor if you have any unusual problems while you are using this medication.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from light, excess heat and moisture (not in the bathroom). You may store mesalamine suppositories in the refrigerator, but do not freeze them. Once you open the foil package of mesalamine enemas use all the bottles promptly, as directed by your doctor.