Canasa400 mg

Mesalazine (5-aminosalicylic acid, 5-ASA) is an anti-inflammatory medicine used for:

• Treatment of mild to moderate ulcerative colitis, including proctitis and proctosigmoiditis
• Maintenance of remission in ulcerative colitis, to reduce the frequency of relapse
• Adjunctive or maintenance treatment in Crohn's disease, in some clinical settings, though evidence of benefit is less well established than for ulcerative colitis

Topical (rectal) mesalazine, used alone or in combination with oral therapy, is often the preferred first-line treatment for disease confined to the distal colon and rectum, and combining oral and rectal therapy is generally more effective than either route alone for appropriately located disease.

Contains mesalazine (5-aminosalicylic acid) as the active ingredient, available as oral enteric-coated or delayed/extended-release tablets and granules (various strengths), and as rectal formulations including suppositories, foam, and enemas.

Mesalazine is the active anti-inflammatory component of the older drug sulfasalazine, isolated to work directly in the gut without the sulfa-related component that caused many of sulfasalazine's side effects. It is the first-line treatment for mild to moderate ulcerative colitis, both for treating active flares and for maintaining remission afterward, and is available as oral tablets/granules and as rectal suppositories, foam, or enemas for disease affecting the lower colon and rectum. It has an excellent overall safety profile compared to other IBD medicines, though it carries a recognized, if uncommon, risk of kidney inflammation with long-term use, which is why periodic kidney function monitoring is recommended.

Therapeutic Class: Aminosalicylate (Gastrointestinal Anti-inflammatory)

Mesalazine formulations are specifically designed to delay release until the drug reaches the colon (via pH-dependent coatings, delayed-release mechanisms, or slow-release granules), since mesalazine works locally within the gut lining rather than through systemic absorption. It is partly metabolized in the intestinal mucosa and liver to N-acetyl-5-ASA, and is excreted mainly in the urine (in acetylated form) and, particularly during active disease with diarrhoea, a variable proportion in the faeces.

• Swallow oral tablets whole, without chewing or crushing, since this can disrupt the delayed-release coating designed to deliver the drug to the colon
• For rectal enemas, shake well before use; administer rectally, ideally at bedtime, and try to retain the enema for at least 20-40 minutes for optimal effect
• For rectal suppositories, insert into the rectum as directed; the suppository does not need to be removed afterward
• Avoid prolonged or excessive sun exposure while using mesalazine, particularly rectal formulations, given a reported association with photosensitivity in some patients
• Nonadherence to prescribed 5-ASA regimens has been shown to significantly increase relapse risk - take doses consistently, even when feeling well

The following should be assessed by a healthcare professional before combining with mesalazine:

• Azathioprine and 6-mercaptopurine: mesalazine may increase the myelosuppressive (blood-count-lowering) effects of these immunosuppressant medicines when used together; blood count monitoring is important if combined.
• Other nephrotoxic medicines (such as NSAIDs): may increase the risk of kidney effects when combined with mesalazine.
• Warfarin: mesalazine may enhance the anticoagulant effect in some patients; monitoring is advisable.
• Live vaccines: generally not a specific concern with mesalazine alone (unlike immunosuppressive IBD therapies), but should be discussed with your treating team given the underlying condition.

Common side effects

• Headache
• Nausea, abdominal pain, dyspepsia
• Flatulence
• Diarrhoea (can be difficult to distinguish from worsening colitis - see precautions)

Serious side effects (seek urgent medical attention)

• Mesalazine-induced nephritis and renal dysfunction: can occur with long-term use; periodic kidney function monitoring is recommended for patients on continuous oral maintenance therapy.
• Acute intolerance syndrome: cramping, acute abdominal pain, and bloody diarrhoea, sometimes with fever, headache, and rash, occurring in a small proportion of patients and difficult to distinguish from a colitis flare; discontinue promptly if suspected and seek medical advice.
• Rare but serious effects: pleuritis, pericarditis, myocarditis, pancreatitis, and cholestatic hepatitis have been reported.
• Serious skin reactions (rare): Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS syndrome, or acute generalized exanthematous pustulosis - fever, blistering or peeling skin, mouth sores, or widespread rash require immediate medical attention.
• Signs of a severe allergic reaction: difficulty breathing or swallowing, rapid heartbeat, swelling of the face or throat.

Pregnancy

Mesalazine is generally considered safe for use during pregnancy, and maintaining disease control during pregnancy is important, since active ulcerative colitis itself carries risks to both mother and baby; use should be guided by your treating gastroenterologist.

Breastfeeding

Mesalazine is generally considered compatible with breastfeeding by gastroenterology guidelines, given its predominantly local action and low systemic absorption; discuss any specific concerns with your treating team.

• Renal function monitoring: periodic kidney function testing is recommended for patients on continuous oral maintenance therapy, given the recognized, if uncommon, risk of mesalazine-induced kidney inflammation with long-term use.
• Acute intolerance syndrome: be alert for cramping, acute abdominal pain, and bloody diarrhoea that could represent this reaction rather than worsening colitis; if suspected, contact your doctor and consider discontinuing mesalazine.
• Sulfa allergy: unlike sulfasalazine, mesalazine does not contain the sulfa component and can generally be used in patients with a sulfa allergy; however, some patients who have had a hypersensitivity reaction to sulfasalazine may also react to mesalazine or related compounds, so any prior reaction should be discussed with your doctor.
• Do not crush or chew delayed/extended-release tablets, since this can disrupt the mechanism designed to deliver the medicine to the affected part of the gut.
• Nonadherence significantly increases relapse risk; take mesalazine consistently as prescribed, even during periods of remission.

Mesalazine has a wide margin of safety, and significant toxicity from moderate overdose is uncommon; excessive doses may be expected to cause more pronounced gastrointestinal effects (nausea, vomiting, diarrhoea) and, with very large or sustained overdose, an increased risk of kidney effects. Suspected significant overdose should be evaluated by a healthcare professional; treatment is generally supportive.

Store oral tablets and granules at room temperature, protected from moisture and light. Store rectal suppositories and enemas as directed on the specific product's label, often at room temperature or refrigerated depending on the formulation; check the specific product's instructions.

• Renal impairment: Contraindicated in severe impairment; use with caution and regular monitoring in mild to moderate impairment.
• Hepatic impairment: Contraindicated in severe impairment; use with caution in milder impairment.
• Children: Used for ulcerative colitis in children above the specific product's minimum age (commonly 2-3 years and older, or 5 years and older depending on the product), with weight-based dosing determined by the treating paediatric gastroenterologist.
• Elderly: No specific dose adjustment is generally required based on age alone, though renal function should be monitored, given age-related decline in kidney function.

Mesalazine is used both for treating an active ulcerative colitis flare (typically at a higher dose for several weeks until remission is achieved) and for long-term, ongoing maintenance therapy at a lower dose to reduce the risk of relapse, since ulcerative colitis is a chronic, relapsing-remitting condition. Continuous, long-term use is common and generally well tolerated, with periodic kidney function monitoring as recommended by the treating gastroenterologist.

Drug Class: 5-aminosalicylic acid (5-ASA) derivative

The exact mechanism by which mesalazine reduces inflammation in the gut lining has not been fully established, but it is believed to act locally within the intestinal lining (rather than through a systemic effect) to reduce the production of inflammatory chemical messengers, including prostaglandins and leukotrienes, and may also influence gut bacterial gene expression. This local anti-inflammatory action reduces the inflammation, ulceration, and bleeding characteristic of ulcerative colitis.

Mesalazine is used in children with ulcerative colitis, typically from around 2-5 years of age depending on the specific product, with dosing based on body weight (commonly 15-20 mg/kg for treatment in children aged 5-15 years, up to a maximum of about 1 g in some formulations, or as otherwise directed by the treating paediatric gastroenterologist). It is contraindicated in very young children (under 2-3 years, per specific product labeling).