Medical Editor: John P. Cunha, DO, FACOEP
Canasa (mesalamine) is an anti-inflammatory drug used to treat ulcerative colitis, proctitis, and proctosigmoiditis. Canasa is also used to prevent the symptoms of ulcerative colitis from recurring. Common side effects of Canasa include:
- rectal pain,
- pain when inserting the suppository,
- stomach pain or cramps,
- sore throat,
- flu symptoms,
- tired feeling, or
- skin rash.
Tell your doctor if you have unlikely but serious side effects of Canasa including:
- worsening stomach pain or cramping,
- worsening bloody diarrhea, fever, and
- severe or prolonged headache.
The usual dosage of Canasa 1000 mg suppositories is one rectal suppository 1 time daily at bedtime. Other drugs may interact with Canasa rectal. Tell your doctor all prescription and over-the-counter medications and supplements you use. During pregnancy, Canasa should be used only when prescribed. This medication passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breastfeeding.
Our Canasa (mesalamine) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using mesalamine rectal and call your doctor at once if you have severe stomach pain, cramping, fever, headache, and bloody diarrhea.
Less serious side effects may include:
- mild nausea, vomiting, stomach cramps, diarrhea, gas;
- fever, sore throat, or other flu symptoms;
- rectal pain, constipation;
- headache or dizziness;
- tired feeling; or
- skin rash.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.
Read the entire detailed patient monograph for Canasa (Mesalamine)
The most serious adverse reactions seen in CANASA clinical trials or with other products that contain or are metabolized to mesalamine are:
- Renal Impairment [see WARNINGS AND PRECAUTIONS]
- Mesalamine-Induced Acute Intolerance Syndrome [see WARNINGS AND PRECAUTIONS]
- Hypersensitivity Reactions [see WARNINGS AND PRECAUTIONS]
- Hepatic Failure [see WARNINGS AND PRECAUTIONS]
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The most common adverse reactions in adult patients with mildly to moderately active ulcerative proctitis in double-blind, placebo-controlled trials are summarized in the Table 1 below.
Table 1: Adverse Reactions Occurring In More Than 1% of Mesalamine Suppository Treated Patients (Comparison to Placebo)
(n = 177)
(n = 84)
In a multicenter, open-label, randomized, parallel group study in 99 patients comparing the CANASA 1000 mg suppository administered nightly to that of the mesalamine 500 mg suppository twice daily. The most common adverse reactions in both groups were headache (14%), flatulence (5%), abdominal pain (5%), diarrhea (3%), and nausea (3%). Three (3) patients discontinued medication because of an adverse reaction; one of these adverse reactions (headache) was deemed possibly related to study medication. The recommended dosage of CANASA is 1000 mg administered rectally once daily at bedtime [see DOSAGE AND ADMINISTRATION].
In addition to the adverse reactions reported above in clinical trials involving CANASA, the adverse reactions listed below have been identified during post-approval use of CANASA and other mesalamine-containing products. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
- Body as a Whole: drug fever, fatigue, lupus-like syndrome, medication residue
- Cardiac Disorders: myocarditis, pericarditis, pericardial effusion [see WARNINGS AND PRECAUTIONS]
- Eye disorders: eye swelling
- Gastrointestinal Disorders: abdominal cramps, abdominal distension, anal pruritus, anorectal discomfort, constipation, feces discolored, flatulence, frequent bowel movements, gastrointestinal bleeding, mucus stools, nausea, painful defecation, pancreatitis, proctalgia, rectal discharge, rectal tenesmus, stomach discomfort, vomiting
- Hepatic Disorders: cholestatic jaundice, hepatitis, jaundice, Kawasaki-like syndrome including changes in liver enzymes, liver necrosis, liver failure
- Hematologic Disorders: agranulocytosis, aplastic anemia, thrombocytopenia
- Neurological/Psychiatric Disorders: Guillain-Barre syndrome, peripheral neuropathy, transverse myelitis
- Renal Disorders: interstitial nephritis, renal failure, minimal change nephropathy [see WARNINGS AND PRECAUTIONS]
- Respiratory, Thoracic and Mediastinal Disorders: hypersensitivity pneumonitis (including allergic alveolitis, eosinophilic pneumonitis, interstitial pneumonitis)
- Skin and Subcutaneous Tissue Disorder: alopecia, erythema, erythema nodosum, pruritus, psoriasis, pyoderma gangrenosum, urticaria
- Urogenital: reversible oligospermia
Read the entire FDA prescribing information for Canasa (Mesalamine)
© Canasa Patient Information is supplied by Cerner Multum, Inc. and Canasa Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.