Medicines & Supplements A to Z > Mesalazine


Last updated on 25/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Mesalazine

ALTERNATIVE NAME: Mesalamine, 5-aminosalicylic acid, 5-ASA

CHINESE NAME: 美沙拉嗪, 5-氨基水楊

BRAND NAME(S) IN HONG KONG: Asacol, Salofalk, Pentasa

DRUG CLASS: Gastrointestinal drugs

SUB CLASS: Aminosalicylates

USED FOR: Ulcerative Colitis

– 250mg, 500mg (tablets)
– 250mg, 500mg, 1g (suppositories)
– 10mg/ml, 4g/100ml, 4g/60ml (enema)
– 250mg, 400mg, 500mg (enteric-coated tablets)
– 1.5g, 2g, 3g, 4g (enteric-coated prolonged-release granules)
– 1.2g (enteric-coated prolonged release tablets)
– 1g (prolonged-release tablets)

What is Mesalazine for?

Inflammatory bowel disease is a collection of diseases where patients have inflamed large intestines. People often feel stomach pain, having bloody stool, diarrhea and weight loss. Mesalazine is used to suppress inflammation in ulcerative proctitis, a type of inflammatory bowel disease which normally takes place in the latter part of the large intestines.

How to use it?

Mesalazine is available in tablets, enteric-coated tablets, enteric-coated prolonged-release tablets, enteric-coated prolonged-release granules and prolonged-release tablets for oral use. For rectal use, suppositories and enemas are available. 

Swallow the tablets or capsules as a whole. Mezavant and Pentasa tablets should be taken with meals while Salofalk tablets should be taken an hour before meals with much liquid. For other oral formulations, it can be taken with or without food.

For rectal formulations, use as directed by the physician or pharmacist.

Ulcerative Colitis
Child above 6 years of age and weighed more than 40 kg, adult and elderly

Asacol enema:Rectosigmoid region: 1 g daily for 4-6 weeks. 

Descending colon: 2 g daily for 4-6 weeks. 

Asacol suppository: 0.75-1.5 g daily in divided doses.
Pentasa suppository or enema:Acute treatment: 1 g daily for 2-4 weeks. 

Maintenance: 1 g daily.

Salofalk enema:2 g once daily at bedtime.
Asacol 400 mg tablet:Acute attack: Initially, 2.4 g daily in divided doses. 

Maintenance of remission: 1.2-2.4 g once daily or in divided doses.

Mezavant prolonged-release tablet:Acute attack: Initially, 2.4-4.8 g once daily. 

Maintenance of remission: 2.4 g once daily. 

Pentasa tablet or prolonged-release tablet:Acute attack: Initially, up to 4 g daily in 2 or 3 divided doses. 

Maintenance of remission: Initially, 2 g once daily, then adjusted individually.

Pentasa prolonged-release granules:Acute attack: Initially, up to 4 g daily in 2-4 divided doses. 

Maintenance of remission: 2 g once daily.

Salofalk tablet:Initially, 1.5-3 g daily in 3 divided doses.

Maintenance of remission: 1.5 g daily in 3 divided doses.

Salofalk granule:Initially, 1.5-3 g once daily or in 3 divided doses. 

Maintenance of remission: 1.5 g daily in 3 divided doses.


Child above 6 years of age and weighed less than 40 kg

Salofalk tablets or granules:Acute attack: Initially, 30-50 mg/kg daily in divided doses, then adjusted individually. Max: 75 mg/kg daily. 

Maintenance of remission: Initially, 15-30 mg/kg daily in divided doses, then adjusted individually.

What are the side effects of Mesalazine?

Common side effects of Mesalazine include arthralgia, cough, dizziness, nephrolithiasis and gastric discomfort. Myalgia, agranulocytosis, inflammations and cholestasis are less likely to occur. 

Who should not take Mesalazine?

– Patients with blood clotting problems
Pregnant and breastfeeding women
– People who are allergic to Mesalazine and any components of the formulations

Pharmacist Tips:

– IBD patients should avoid dairy products, sugary and fatty food.
– Seek medical attention if symptoms worsen, such as bleeding, fever and exacerbated abdominal pain.
– Ensure you receive adequate hydration so as to prevent nephrolithiasis.

Common dosing schedule:
Refer to the package insert or table above for the schedule. Beware of the brands, dosage form and strength you are using. It may lead to a different schedule from the others.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Mesalazine may interact with:
– Antacids, e.g. Aluminium hydroxide, Calcium carbonate, Magnesium hydroxide
– Cardiac glycosides, e.g. Digoxin, Digitoxin
– Myelosuppressive agents, e.g. Cladribine, Methotrexate, Cyclophosphamide
– NSAIDs, e.g. Ibuprofen, Aspirin, Ketoprofen

Mesalazine may interact with many other medications. Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Mesalazine in Hong Kong? 

In Hong Kong, Mesalazine is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Mesalazine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.