Mesalazine works by reducing inflammation of the large intestine (colon and rectum) and therefore improves symptoms related to ulcerative proctitis and colitis. There are many different preparations and brands of mesalazine (Salofalk, Asacol, Pentasa, Mezavant, Colazide, Ipocol, Mesren). Some brands have proven advantages in certain patients but overall they are similar. I tend to recommend Salofalk granules first-line because of once daily dosing.
There is very good evidence from many clinical trials over more than 20 years that mesalazine is of significant benefit in patients with ulcerative procto-colitis. It works best in patients with mild to moderate exacerbations (or relapses) and in maintaining remission (keeping you well). It decreases the chance of a relapse from about 70% to 30% each year.
Mesalazine may be taken as tablets (or granules) by mouth (and must be swallowed whole and not chewed), or inserted into the bottom (rectum) as foam or liquid enemas or suppositories (for patients with proctitis only).
The benefits of mesalazine treatment may not be evident for 4 weeks.
Patients who respond to mesalazine usually remain on it for many months and perhaps several years as long as the blood test monitoring remains satisfactory.
Fortunately many patients do not suffer any side effects with this treatment. Nausea, headache, diarrhoea and abdominal pain are the most common (1:10) side effects. Rare side effects include: pancreatitis, kidney failure, unexplained bruising, bleeding, sore throat, fever or rashes. Should you develop any of these troublesome symptoms please tell either your GP or me. Mesalazine should be avoided in patients with aspirin hypersensitivity.
You will need to have blood tests (full blood count, liver & kidney function) about 3 months after starting drug and then after each year because of the drug’s rare adverse effects on the bone marrow (it suppresses production of white cells & platelets) and kidney damage (interstitial nephritis). If the blood tests become abnormal, your doctor will advise you to stop the drug and normally, the test results return to normal.
Negligible amounts cross placenta or are found in breast milk; therefore it appears safe during pregnancy and breast feeding.
Keep all medicines out of the reach of children. Never give any medication prescribed for you to anyone else. It may harm them even if their symptoms are the same as yours.