Polypharmacy: should we or shouldn't we?

Much has been written recently in The Psychiatrist about how psychiatrists should manage antipsychotic polypharmacy. Taylor ¹ could hardly be more emphatic: ‘evidence supporting antipsychotic polypharmacy has, if anything, diminished and evidence suggesting or demonstrating harm has grown’. He concludes that ‘mounting awareness of the probable futility of antipsychotic polypharmacy is reflected in the latest guidance issued by the National Institute for Health and Clinical Excellence’.

Lepping & Harbone ² draw attention to the need for a ‘more balanced view with regard to polypharmacy in a patient group that is often non-responsive’. We would like to address issues raised by Odelola & Ranceva. ³

First, Odelola & Ranceva speculate that the persistence of antipsychotic polypharmacy despite repeated guidance against it may indicate that this is one area where clinical practice is ahead of research evidence. They reiterate Lepping & Harbone's point that in the case of polypharmacy the evidence provides no support either way - hardly a ringing endorsement. Additionally, they praise the excellent recommendations by Langan & Shajahan. ⁴ In the context of their letter we would be concerned that this is potentially misleading. Langan & Shajahan urge extreme caution if one uses polypharmacy, supported by thorough explanatory documentation, rigorous monitoring and ongoing review. They conclude with the caveat that the ‘worrying relationship’ between the use of polypharmacy and mortality merits investigation and that it remains ‘more art than science’. The message to take home seems to be ‘avoid if possible’.

Among the routes to antipsychotic polypharmacy, nearly all of the researchers quoted here identify the failure to complete a switch from one agent to the other as a starting point for polypharmacy - this surely represents an opportunity for psychiatrists to tackle unplanned and inappropriate polypharmacy. The risks of high-dose prescribing should also be borne in mind.

The fact that there are probably increasing rates of polypharmacy prescribing should not be misinterpreted as evidence in support of it - once it was doubted by many that the world was spherical! Evidence suggests that the two polypharmacy scenarios outlined in the National Institute for Health and Clinical Excellence guidelines, ⁵ cross-tapering and adding an antipsychotic to clozapine, appear reasonable. Outside these scenarios the risks v. benefits demand serious concern. We would echo Odelola & Ranceva's call to be openminded about polypharmacy. This would extend to entertaining the possibility that the practice should be jettisoned in many cases. To cope with any overwhelming feelings of therapeutic nihilism, we would direct readers to Williams et al's editorial. ⁶