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Midazolam is a short-acting water-soluble benzodiazepine (at pH less than 4), a member of a new class of imidazobenzodiazepine derivatives. At physiological pH the drug becomes much more lipid soluble. Water solubility minimises pain on injection and venous thrombosis compared with diazepam administered in organic solvent. Midazolam is a hypnotic-sedative drug with anxiolytic and marked amnestic properties. To date it has been used mostly by the intravenous route, for sedation in dentistry and endoscopic procedures and as an adjunct to local anaesthetic techniques. It has proved less reliable than thiopentone, but preferable to diazepam, as an intravenous induction agent and is unlikely to replace the other well established drugs. However, due to the cardiorespiratory stability following its administration, midazolam is useful for anaesthetic induction in poor-risk, elderly and cardiac patients. The short elimination half-life (1.5-3.5h) and the absence of clinically important long acting metabolites make midazolam suitable for long term infusion as a sedative and amnestic for intensive care, but clinical trials have yet to be completed. Thus, a combination of properties make midazolam a useful addition to the benzodiazepine group.

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Mesalazine (5-aminosalicylic acid; mesalamine), the active moiety of sulphasalazine (salazosulfapyridine), is available in specially formulated oral and rectal forms for the treatment of active ulcerative colitis of mild to moderate severity and for maintenance therapy during disease remission. Tablets or capsules coated with acrylic-based resin and tablets containing microgranules coated with ethylcellulose deliver mesalazine to the distal small intestine and colon, thus avoiding the need for the carrier, sulphapyridine, which is responsible for many of the adverse effects associated with sulphasalazine. Since mesalazine is released in the small intestine from some coated preparations in contrast to sulphasalazine, these oral formulations have therapeutic potential in Crohn's disease. A limited number of therapeutic trials suggest that orally administered mesalazine 1.5 to 2.4g daily is of similar efficacy to sulphasalazine 2 to 3g daily in patients with mild to moderate ulcerative colitis. The efficacy of mesalazine enemas has been more widely investigated, a dose of 1 to 4g once daily being consistently more effective than placebo and apparently similar to enemas of prednisone 25mg or oral sulphasalazine 3g. Initial results suggest that mesalazine 4g enemas may be more effective than those containing hydrocortisone 100mg. Mesalazine and sulphasalazine in approximately equivalent oral dosages are similarly effective in maintaining remission in ulcerative colitis. Orally administered coated mesalazine is generally well tolerated by about 85% of patients allergic to or intolerant of sulphasalazine, the remainder experiencing similar reactions to both drugs. Adverse effects of mesalazine enemas are confined to local irritation and effects resulting from enema-tip insertion. Thus, orally administered coated mesalazine is a suitable alternative to sulphasalazine in the treatment of patients with mild to moderate active distal ulcerative colitis and for maintaining remission particularly in patients allergic to or intolerant of sulphasalazine. In patients who find enema therapy acceptable, mesalazine enemas are effective and well tolerated.