A multicenter double-blind randomized crossover study comparing the impact of dorsal subthalamic nucleus deep brain stimulation versus standard care on apathy in Parkinson's disease: a study protocol.

BACKGROUND: Neuroimaging studies suggest an association between apathy after deep brain stimulation (DBS) and stimulation of the ventral part of the subthalamic nucleus (STN) due to the associative fibers connected to the non-motor limbic circuits that are involved in emotion regulation and motivation. We have previously described three patients with severe apathy that could be fully treated after switching stimulation from a ventral electrode contact point to a more dorsal contact point. OBJECTIVES: To determine whether more dorsal stimulation of the STN decreases apathy compared to standard care in a multicenter randomized controlled trial with a crossover design. METHODS: We will include 26 patients with a Starkstein Apathy Scale (SAS) score of 14 or more after subthalamic nucleus (STN) deep brain stimulation (DBS) for refractory Parkinson's disease. This is a multicenter trial conducted in two teaching hospitals and one university medical center in the Netherlands after at least 3 months of STN DBS. Our intervention will consist of 1 month of unilateral dorsal STN stimulation compared to treatment as usual. The primary outcome is a change in SAS score following 1 month of DBS on the original contact compared to the SAS score following 1 month of DBS on the more dorsal contact. Secondary outcomes are symptom changes on the Movement Disorders Society-Unified Parkinson's Disease Rating Scale motor part III, Montgomery-Åsberg Depression Rating Scale, 39-item Parkinson's disease questionnaire, Parkinson's disease impulsive-compulsive disorders questionnaire, changes in levodopa-equivalent daily dosage, apathy rated by the caregiver, and burden and quality of life of the caregiver. TRIAL REGISTRATION: ClinicalTrials.gov NL8279. Registered on January 10, 2020.

[Carbamazepine and quetiapine: a neglected, but highly relevant interaction]. / Carbamazepine en quetiapine: een onderbelichte, maar zeer relevante interactie.

We describe a case of concomitant use of carbamazepine and quetiapine, with a highly relevant interaction that requires attention. The combination of these drugs can be prescribed in psychiatry, for example in bipolar disorder, but also in other disciplines. Pharmacotherapy is one of the cornerstones in the treatment of bipolar disorders, and a combination of drugs is frequently used. Carbamazepine, an anti-epileptic drug that is effective as a mood stabilizer, and quetiapine, a second-generation antipsychotic, are both recommended in the Dutch guideline. Besides monotherapy is a combination of both drugs possible. It is striking that carbamazepine and quetiapine have a strong pharmacokinetic interaction via the metabolizing liver enzyme, CYP3A4. This interaction results in a factor 10 reduction of quetiapine blood levels. This may result in a possible loss of clinical efficacy of quetiapine.