Minder kan meer zijn; terugdringen en rationaliseren van polyfarmacie bij schizofrenie

Though guidelines for the treatment of schizophrenia recommend monotherapy with antipsychotic drugs, about 30% of patients are treated with 2 or even more antipsychotics. This widespread use of antipsychotic polypharmacy may indicate some rationale for polypharmacy, despite the lack of evidence supporting its effectivity.
For some patients polypharmacy might offer a better option than guideline-recommended monotherapy. On the basis of pharmacological and clinical evidence we developed an individualized polypharmacy revision procedure, using shared decision making supported by an algorithm aiming at optimal effective and tolerable treatment only recommending polypharmacy in specific cases, where no alternatives are at hand. We expect patients who receive polypharmacy treatment to benefit from this individualized approach by improved personal and social performance, and experiencing less distress because of symptoms and side effects without increased relapse rates. This is a multicenter naturalistic open label randomized clinical trial comparing a polypharmacy revision strategy with active control using continued polypharmacy and personal and social performance as a primary outcome. Secondary outcomes are severity of symptoms, relapse rates, side effects, health related costs, consumer-involvement and the feasibility of the revision strategy (proportion of realized indicated monotherapies). To be included in the trial are patients with schizophrenia who are being treated with at least 2 antipsychotics and who are prepared to consider revision of their medication. Follow-up is one year after inclusion and randomization.

The widespread use of antipsychotic polypharmacy may reflect some rationale of polypharmacy despite the lack of evidence to support this. For some patients polypharmacy may be a better option than guideline recommended monotherapy. In view of pharmacologic and clinical evidence we developed an individualized polypharmacy revision procedure, using an algorithm aiming at optimal effective and tolerable treatment, only allowing rational polypharmacy in specific cases if no alternatives are at hand. We expect patients to benefit from this individualized approach by better personal and social performance, less bothering symptoms and/or side effects, without experiencing more relapses, compared to continued polypharmacy treatment.

April 1 2014: 3 months preparation (writing the protocol, instruction of clinicians using the
polypharmacy revision algorithm, formation of consumer advisory board),

July 1 2014 - July 1 2015: 12 months for selection of eligible patients, informed consent, inclusion and randomization,

July 1 2014 - July 1 2016: experimental phase: one year of follow-up with 3 six sixmonthly assessments per patient

July 1 2016 - Oktober 1 2016 End of trial, analysis and writing reports

All patients in the experimental group will be involved in an intention to treat strategy to rationalize and if possible reduce their polypharmacy during one year. To this purpose an algorithm has been developed assigning the appropriate treatment propositions. The algorithm will be used on the basis of intention to treat and shared decision-making. The shared decisions will determine the assigned medication regimens that are compared with ongoing polypharmacy in the control condition. This means that patients who do not chose to switch to monotherapy despite the algorithms recommendation remain in the analysis. The feasibility of the strategy is a secondary outcome measure. According to the algorithm the experimental group is distinguished into a clozapine treated and a non-clozapine treated group; the clozapine treated group is further
distinguished into formerly clozapine-monotherapy-tested patients, and not-clozapine-monotherapy-tested patients. While the latter group is switched to clozapine monotherapy, the first is assigned to polypharmacy: a combination of clozapine and either low-dose haloperidol, sulpiride or aripiprazole. The non-clozapine treated group is further distinguished into groups with and without adequate D2 blockade; the latter group is switched to monotherapy with an antipsychotic of their own choice in an adequate dosage regarding D2 blockade. If effective and without intolerable side effects, this antipsychotic monotherapy will be the assigned treatment. If not effective or intolerable side effects arise, these patients, as well as the patients with adequate D2 blockade, just like the clozapine treated group, are distinguished into formerly clozapine-monotherapy-tested patients, and not-clozapine-monotherapy-tested patients. While the latter group is switched to clozapine monotherapy, the first is assigned to clozapine polypharmacy with low dose haloperidol, sulpiride or aripiprazole.

This decision tree does acknowledge the rationale of polypharmacy if both adequate D2 blockade and clozapine monotherapy have proven to be ineffective, and in that case assigns polypharmacy in the form of combining clozapine and low-dose haloperidol, sulpiride or aripiprazol combinations, which are the most rational combinations to consider, though sulpiride with most evidence (Leucht et al, 2011, Sommer et al, 2011).The result of the algorithm will either be: non-clozapine antipsychotic monotherapy, clozapine monotherapy, clozapine polypharmacy with low-dose haloperidol, sulpiride or aripiprazole, or in special cases, e.g. when clozapine cannot be tolerated (either in monotherapy or in combination) and non-clozapine antipsychotic monotherapy does not suffice, polypharmacy with non-clozapine antipsychotics as a last resort. The control group will continue to take polypharmacy as before, also intention to treat