Pentasa (TM) Mesalazine is one of the newer Aminosalicylates , a class of drug used as an anti-inflammatory.

Indication: treatment of mild to moderate ulcerative collitis and Crohn's disease (intestinal infammatory conditions)

Mesalazine is a bowel specific drug, that is metabolized in the gut and has its predominant actions there- thereby having fewer systemic side effects.

Mesalamine, also known as 5-aminosalicylic acid (5-ASA), is an anti-inflammatory drug used to treat inflammation of the rectum, mild to moderate ulcerative colitis and inflammation of the lower colon . Chemically, it is 5-amino-2-hydroxybenzoic acid. The empirical formula is C 7 H 7 NO 3 and its molecular weight is 153.14.

It is sold in the U.S. under the names:

• CANASA: Rectal suppository with 500 mfg of mesalamine in a base of Hard Fat NF.
• ROWASA: Rectal suppository & suspension enema .
• PENTASA: Suspension enema.
• ASACOL: Suspension enema & 400mg tablets

Known side effects

• Cramping
• Sudden severe stomach pain
• Bloody diarrhea
• Fever
• Severe headache
• Rash
• Nausea
• Hepatic impairment
• Agranulocytosis,Aplastic anaemia, Neutropenia, Thrombocytopenia- any sore throats, bruising or excesssive bleeding should be reported to the prescribing physician and a Full blood count (rbc and wbc) as well as liver function test be performed
• Myocarditis
• Methaeoglobinaemia

Dosing depends on preparation- the UK guidelines from the British National Formulary are: Asacol: 400mg tablets- 6 tablets daily for an acute attack, tablets for prophylaxis. Not recommended for children

NB- preparations that lower stool pH (such as lactulose, a laxative) will affect the binding of Mesalazine in the bowel and will therfore reduce its efficacy.

Pentasa 4g daily for an acute attack, 1.5g daily for prohpylaxis

Sources for more information- British National Formulary, Davidsons Practice of Medicine, Oxford Textbook of Medicine, any other text book of medicine-