Premedication with lorazepam before bone marrow biopsy.

Fifty patients were randomised in a double blind placebo controlled study to examine the influence of lorazepam (4 mg orally) before bone marrow aspiration and trephine biopsy. Assessment was made by a visual analogue linear pain scale compiled after the procedure and again 24 hours later. There was no difference in the pain recalled immediately after the procedure between the two groups, but the next day the patients who had received lorazepam showed amnesia with a 60% (p less than 0.01) reduction in the pain scale; 36% of the patients in this group had no recall of the procedure at all. There was no amnesic effect in the group taking placebo. Side effects were few, and it is concluded that lorazepam is a useful premedication agent before bone marrow biopsy.