Metformin prescription in psychiatry
Shui.chi Suetani, Stephen Parker, David Crompton, Frances Dark, Nicole Korman & Dan Siskind
The importance of physical health in people with SMD is now well recognised.2 Even though there is evidence to suggest that the rate of screening people with SMD for metabolic issues in Australia outperforms the international average, the rate of intervention still lags behind that of identification,3 with physical ill health among those with SMD often under-diagnosed.4 A practical tool to facilitate secondary prevention by limiting antipsychotic associated weight gain is of clear relevance to psychiatry.
There is further evidence that metformin may also have significant clinical benefit even for those individuals who are already prescribed clozapine. A recent meta-analysis by Siskind et al.5 found that people on metformin achieved significantly more weight loss compared to those on placebo. Given this, there is now a clinical trial in preparation in Queensland that is looking at the efficacy of metformin treatment in people with SMD.
It is relevant to highlight further some important issues associated with the prescription of metformin in psychiatry. First, there is the need for a comprehensive discussion with patients and their families about the implications of off-label prescription, and a clear documentation of the rationale and the ongoing management plan in the medical record. Furthermore, a registrar may require consultant approval before making an off-label prescription. Attention to the inclusion in registrar training programmes regarding the practical use of metformin may be of great benefit.
Another issue we have seen debated for several years is whether the psychiatrist should take a lead role in chronic physical health intervention or if this should be managed in primary care. While some psychiatrists may argue for taking a proactive interest in the physical health of our patients, others may see this as outside of our clinical expertise and professional comfort. This is an important issue we intend to further explore in future. Nevertheless, the proposed metformin prescribing tool is a useful resource in assisting psychiatrists and registrars to help address the persisting mortality and morbidity gaps among our patients.