Mesalazine is an anti-inflammatory drug belonging to the aminosalicylate class. It is the active component of sulfasalazine and is primarily used for the induction and maintenance of remission in patients with mild to moderate ulcerative colitis (UC) and, in some formulations, Crohn’s Disease. Mesalazine works locally in the bowel, exerting its therapeutic effects directly on the inflamed lining of the colon and rectum, reducing inflammation, and preventing flare-ups of the disease. This formulation often refers to a single, high-dose tablet or extended-release preparation designed for convenient, less frequent dosing.

Mesalazine contains mesalazine, also known as mesalamine or 5-aminosalicylic acid (5-ASA). It is used to treat inflammatory bowel disease, most commonly ulcerative colitis , and in some cases Crohn’s Disease affecting the large bowel. These conditions cause long-lasting inflammation of the intestinal lining, which can result in symptoms such as frequent diarrhea, stomach pain, rectal bleeding, and an urgent need to use the toilet.

Mesalazine reduces inflammation by blocking the production of chemical messengers, including prostaglandins and leukotrienes, that trigger swelling and irritation in the gut. By lowering inflammation, the medicine relieves symptoms, promotes healing of the intestinal lining, and helps prevent flare‑ups

Mesalazine is used both to bring symptoms under control during active disease and to help keep the condition stable over time. Even when symptoms improve or disappear, it is important to continue taking the medicine as prescribed, as stopping treatment too early can allow inflammation to return.

People taking mesalazine are usually monitored by their doctor to ensure the treatment remains safe. This may include occasional blood and urine tests, as the medicine can rarely affect kidney function. Patients should seek medical advice if they notice new or worsening symptoms such as ongoing abdominal pain, blood in the stool, skin rashes, fever, or changes in urination.

With regular use and appropriate medical follow-up, Mesalazine plays an important role in controlling inflammation, reducing relapses, and improving day-to-day life for people living with inflammatory bowel disease.

Mesalazine is indicated for:

Induction of Remission in Mild to Moderate Ulcerative Colitis (UC):

Used to control active inflammation and bring the disease into a quiescent state.

Maintenance of Remission in Ulcerative Colitis:

Essential for preventing future flare-ups and maintaining long-term health.

Treatment of Mild to Moderate Crohn’s Disease:

Some formulations are indicated for specific sites of Crohn’s disease, though it is generally less effective than for UC.

Targeted Action:

Delivers the anti-inflammatory agent directly to the inflamed areas of the colon, maximising efficacy and minimising systemic exposure.

First-Line UC Treatment:

Highly effective and well-established as the primary treatment for mild to moderate Ulcerative Colitis.

Safety Profile:

Generally well-tolerated, particularly compared to systemic corticosteroids, making it suitable for long-term maintenance therapy.

Reduced Cancer Risk:

Prolonged use of Mesalazine has been associated with a reduced risk of colorectal cancer in patients with chronic UC.

When taken as directed, Mesalazine is generally safe. Side effects are usually rare, mild, and temporary.

Common Side Effects (Mild and temporary):

• Nausea and Vomiting

• Constipation

• Stomach upset

• Slight drowsiness

Serious Side Effects (Stop taking the medicine and seek urgent medical attention if you experience):

• Severe Allergic Reaction (Anaphylaxis): Rash, swelling of the face, throat, or tongue, difficulty breathing, or dizziness.

• Serious Skin Reactions (Very Rare): Redness, blistering, peeling of the skin (e.g., Stevens-Johnson Syndrome)

• Signs of Liver Damage (Overdose Risk): Yellowing of the skin or eyes (jaundice), persistent nausea, unexplained fatigue, or pain in the upper right abdomen.

• Dosage: The total daily dosage varies based on whether the goal is induction (typically higher doses, e.g., 2.4g to 4.8g daily) or maintenance (typically lower doses, e.g., 1.2g to 2.4g daily). The tablets are usually taken once or twice daily.
• Administration: Swallow the tablet whole. Do not chew, crush, or break the extended-release or coated tablets, as this will compromise the specialised delivery system and cause the drug to be released too early in the stomach, reducing efficacy and increasing systemic side effects.
• Consistency: Take Mesalazine exactly as directed, even after symptoms improve, to maintain remission and prevent relapse.

Mesalazine (5-ASA) is believed to act topically, meaning its therapeutic effect occurs primarily at the site of inflammation within the gastrointestinal wall.

1. Targeted Delivery: The specialised coating on oral Mesalazine formulations ensures that the drug bypasses the stomach and small intestine, releasing high concentrations of the active ingredient directly into the colon.
2. Anti-Inflammatory Action: Once released, Mesalazine acts by locally inhibiting the production of inflammatory mediators within the intestinal wall.
3. Mediator Suppression: It inhibits the activity of cyclooxygenase and lipoxygenase pathways, thereby suppressing the production of prostaglandins and leukotrienes, which are key drivers of inflammation in IBD.
4. Free Radical Scavenging: Mesalazine is also thought to act as an antioxidant by scavenging reactive oxygen species and free radicals, which contribute to tissue damage during active inflammation.

• Long-Term Use: Even if you feel well, continue taking Mesalazine exactly as prescribed. Stopping the medication prematurely is the leading cause of relapse in UC.

• Kidney Monitoring: Regular blood tests to check kidney function (creatinine levels) are necessary throughout the entire course of therapy.

• Watch for Fever and Rash: If you develop a fever, severe headache, or rash shortly after starting Mesalazine, contact your doctor immediately, as this could be a sign of the rare "Acute Intolerance Syndrome."

• Don't Crush: Never crush, chew, or break the tablets, as this destroys the complex delivery system essential for its function.

• Store at room temperature (typically below 25°C or 77°F).

• Keep the container tightly closed and protect the tablets from moisture and light.

• Keep out of reach of children.

• General: Food may affect the dissolution rate of some formulations, so always follow the specific instructions on whether to take your specific Mesalazine formulation with or without food.
• Diet: While no direct food interactions exist, maintaining a diet that supports IBD management is crucial for the drug's overall effectiveness.

• Azathioprine or 6-Mercaptopurine (Immunosuppressants): Concomitant use with Mesalazine may increase the risk of blood disorders (myelosuppression). Requires strict monitoring of complete blood counts (CBC).

• Nonsteroidal Anti-inflammatory Drugs (NSAIDs): Combining Mesalazine with NSAIDs (like Ibuprofen or Naproxen) may increase the risk of kidney toxicity.

• Lactulose or Other Stool Softeners (pH-modifying agents): These can alter the pH in the colon, potentially interfering with the delivery mechanism of some pH-dependent Mesalazine formulations.

• Renal Impairment (Kidney Disease): Increased risk of nephrotoxicity.

• Hepatic Impairment (Liver Disease): Increased risk of hepatotoxicity.

• Pyloric Stenosis (Narrowing of the stomach outlet): May affect the release and delivery mechanism of specialised oral formulations.

• Known Salicylate Hypersensitivity: CONTRAINDICATED.

For maintenance therapy in UC, the daily dose typically ranges from 1.2g to 2.4g (one to two 1200mg tablets). For active UC, the dose may be increased up to 4.8g daily, split into multiple doses.

Overdose is rare due to the drug's targeted release mechanism, but symptoms can include nausea, vomiting, dizziness, and signs of salicylate toxicity (ringing in the ears, rapid breathing). Action Required: Seek immediate emergency medical attention. Treatment involves supportive measures, including monitoring renal and hepatic function, and potentially forced diuresis or hemodialysis in severe cases.

If you miss a dose of Mesalazine, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not double the dose to make up for a missed one.