Although the aetiology of
inflammatory bowel disease remains elusive, many agents are available for the control of symptoms and
inflammation. Knowledge of
drug pharmacology, indications and side effects is essential to ensure the best possible clinical care while minimising toxicity and inappropriate use.
Sulfasalazine consists of
sulfapyridine linked to
mesalazine (5-aminosalicylic acid) via an azobond. Its use is indicated in the treatment of mild to moderately active
ulcerative colitis and in the prevention of relapse in patients with quiescent disease. Patients with mild to moderate colonic or ileocolonic
Crohn's disease also benefit from this
drug, as do a proportion of patients with isolated small bowel disease.
Sulfasalazine has not been uniformly effective in preventing relapse in
Crohn's disease, although many clinicians continue its use in patients who respond initially. A high incidence of side effects which limit
therapy include intolerance,
hypersensitivity reactions and impairment of
male infertility. The newer aminosalicylates offer targeted delivery of
mesalazine to the bowel, with fewer side effects. Topical
mesalazine has proved extremely effective in patients with distal
ulcerative colitis; oral forms are effective in the treatment of mild to moderately active
ulcerative colitis and in relapse. Both types appear to be effective in the treatment of
Crohn's disease, and possibly in preventing relapse. There is no current clinical advantage of one
mesalazine preparation over another, nor is there an indication for their use in
sulfasalazine-treated patients who have satisfactory response without adverse effects.
Corticosteroids are indicated for more severe disease activity where the aminosalicylates have limited efficacy-specifically to induce remission in patients with severe or refractory
ulcerative colitis or
Crohn's disease. They should not be used to maintain disease remission or in the prevention of postoperative recurrence. Topical
corticosteroids allow their local use in distal
colitis with minimal systemic side effects. Long term use is limited by side effects, many of which are dose related, although alternate-day
therapy may lessen the incidence.
Immunosuppressive agents are beneficial for the treatment of refractory
inflammatory bowel disease unresponsive to other medications, and may also facilitate the withdrawal of
steroids in refractory patients.
Mercaptopurine has an added benefit in the treatment of
Crohn's disease fistulae; the role of
cyclosporin in bowel disease has not been established and its use cannot currently be recommended. The potential toxicity of
immunosuppressive agents warrants careful consideration of their use by both physician and patient.
Metronidazole is indicated for the treatment of mild to moderate
Crohn's disease, including perineal disease. Common side effects include
peripheral neuropathy and
nausea.(ABSTRACT TRUNCATED AT 400 WORDS)