Canasa (Mesalamine) Medication

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We don't sell this generic-version medication.
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Canasa is a rectal suppository prescribed for the treatment of adults with mild to moderately active ulcerative proctitis (ulcerative rectal colitis). 

Classified as an aminosalicylate drug, Canasa works by reducing inflammation in the colon’s epithelial cells. It accomplishes this by blocking the enzyme cyclooxygenase (COX) and inhibiting prostaglandin production, both of which contribute to generating an inflammatory response. 

Uses and Dosage 

Before using Canasa and with each prescription refill, thoroughly review its medication guide and patient information leaflet. Consult your doctor or pharmacist for any questions or clarifications. 

Canasa is strictly for rectal use and should be administered whole, not cut or broken.  

Canasa’s dosage is determined based on the patient’s medical condition, response to the treatment, and prescription strength. For the 1000-milligram strength, it is usually inserted rectally once daily at bedtime. If using a lower strength, the doctor may direct the patient to use the medication 1 to 3 times daily, following their instructions carefully. 

To properly use Canasa, follow these steps: 

  1. Prior to bedtime, ensure that you have a bowel movement. 
  2. Detach one suppository from the strip. 
  3. Upright the suppository and cautiously tear open the plastic packaging along the pre-scored line. 
  4. Insert the suppository’s pointed end into your rectum with gentle pressure until fully inserted. 
  5. Try to retain the suppository in your rectum for one to three hours or longer for optimal results. 
  6. Thoroughly wash your hands after each administration. 

Excessive handling of the suppository should be avoided to prevent it from melting due to the body’s heat.  

Canasa may cause staining of clothing, fabrics, and surfaces. Take necessary precautions to avoid staining when using this medication. 

Staying well hydrated is crucial while undergoing Canasa treatment. Remember to drink ample fluids during this time. 

Keep using Canasa until you complete the full prescription, even if you feel improvement at the beginning of treatment. Do not discontinue use without consulting your doctor. 

Keep Canasa at 68°F to 77°F (20°C to 25°C), shielded from heat, light, and humidity. It may also be refrigerated. 

Side Effects 

Listed below are the side effects associated with the use of Canasa. Tell your doctor promptly if you experience any persistent or worsened side effects. 

Common Side Effects 

  • Rectal pain 
  • Pain when inserting the suppository 
  • Headache 
  • Gas 
  • Nausea 
  • Vomiting 
  • Stomach pain or cramps 
  • Diarrhea 
  • Constipation 
  • Fever 
  • Sore throat 
  • Flu symptoms 
  • Dizziness 
  • Tired feeling 
  • Skin rash 

Serious Side Effects 

  • Worsening stomach pain or cramping 
  • Worsening bloody diarrhea or fever 
  • Severe or prolonged headache 

Inform your doctor right away if you experience any of the above-listed severe symptoms. 

Allergic Reactions 

Severe allergic reactions to Canasa are uncommon but seek immediate medical attention if you experience symptoms such as: 

  • Fever 
  • Rash 
  • Swollen lymph nodes 
  • Severe dizziness, 
  • Face/tongue/throat itching or swelling  
  • Difficulty breathing 

This list does not contain all the potential side effects of Canasa. If you experience any other effects not listed above, notify your doctor promptly. 


Before starting treatment with Canasa, inform your doctor and pharmacist if you have any known hypersensitivities, especially to: 

  • Mesalamine 
  • Other aminosalicylates (e.g., balsalazide, olsalazine) 
  • Aalicylates (e.g., aspirin, salsalate) 
  • Sulfasalazine 
  • Other medicines 
  • Any ingredients present in Canasa suppository 

To ensure Canasa is safe for you, disclose to your physician your medical background, specifically regarding any history of: 

  • Kidney problems 
  • Liver disease 
  • Pancreas problems (pancreatitis) 
  • Inflammation of the sac around the heart (pericarditis) 

Inform your doctor and pharmacist about all the medications you are taking, including prescription and over-the-counter drugs, dietary supplements, and herbal products, to minimize the possibility of drug interactions that could impact Canas’s efficacy or raise the likelihood of adverse effects. 

The use of Canasa may affect some laboratory tests, leading to inaccurate results. To prevent such incidents, inform your healthcare provider and lab personnel about your use of this medication. 

If you have skin issues like atopic dermatitis or eczema, Canasa might increase your sensitivity to the sun. Restrict your exposure to sunlight, avoid tanning beds and sunlamps, and wear protective clothing and sunscreen when outdoors. If you experience sunburn, skin blisters, or redness, inform your doctor immediately. 

If you have chickenpox, flu, or any undiagnosed illness, or if you have received a live virus vaccine (such as varicella vaccine), consult a doctor before taking aspirin or aspirin-related medications (such as salicylates) due to the risk of Reye’s syndrome, a rare but serious illness. Canasa is similar to aspirin and should also not be taken by children and teenagers under 18 years old in these circumstances. 

Notify your physician if you are pregnant or planning to conceive, as the potential risks of Canasa to an unborn child are uncertain. 

Inform your doctor if you plan to breastfeed, as mesalamine can pass into breast milk. Discuss the best feeding option for your baby if you are already using Canasa. 

Additional information

Generic name:



Rectal Suppository


500mg, 1000mg

Quantities Available:

30, 90

Quality Prescription Drugs has provided information from third parties intended to increase awareness and does not contain all the information about Canasa (Mesalamine). Talk to your doctor or a qualified medical practitioner for medical attention, advice, or if you have any concerns about Canasa (Mesalamine).