Controlled-release morphine (MST Contin) in advanced cancer. The European experience

The published data relating to the clinical evaluation and use in Europe of oral controlled-release morphine tablets (MST Continus, [MST] Napp Laboratories, United Kingdom) in the treatment of chronic cancer pain are reviewed. There are three evaluable published reports of double-blind randomized controlled studies and a number of prospective open studies and retrospective reviews. There are also several published pharmacokinetic studies and substantial accumulated clinical experience with MST since its introduction in the United Kingdom in 1981. A critical review of the evidence indicates that MST is effective in patients with opioid-responsive pain; that for almost all patients twice-daily administration is sufficient; that the potency ratio compared with standard (immediate-release) oral morphine formulations is one to one; and that the side effect profile is similar. An immediate-release morphine preparation is preferable during the dose titration period when frequent dose adjustment may be required. However, once patients have been stabilized MST is much more convenient and simpler to use than conventional morphine elixirs or tablets and is the preferred formulation for maintenance treatment.