EDITOR—Vidal et al are rightly concerned that information on dose adjustment is not as well supported by evidence as our knowledge about the effectiveness of modern interventions (p 263). 1 But, as they have found, the lack of robust data to guide clinicians on the precautions to take when using drugs is woeful. Therefore, their conclusions come as no surprise to compilers of drug information.

Because there are few accessible studies on dose adjustment in renal impairment, the British National Formulary (BNF) has to rely on summaries of product characteristics, which reflect data submitted for gaining marketing …