Assessing clinical trials--trial discipline.

In this article several questions about trial discipline are raised that must be answered satisfactorily before the clinical study begins. It is important to decide whether a fixed-dose or a variable-dose regimen is appropriate-they are different treat- Pktpce ments-to realise that including a vehicle treatment (or placebo) may be unethical and is not a necessary part of clinical trial methodology. Consideration should be given to ways of enhanc-llw-p ing or monitoring compliance with treatment and follow-up of patients. The routine for examining patients should be carefully \ ; determined and, when appropriate, a time table drawn up. Intraocular pressure, for example, shows diurnal variation and '/ so should be measured at fixed times by one tonometrist. Blood ElIDEMIOLOGY pressure should also be recorded under standard conditions- u.'ATE for example, sitting blood pressure after two minutes' sitting and specified cut-off for diastolic pressure.