A Comparative Study between Olanzapine and Risperidone Regarding Drug-Induced Electrocardiographic Changes

Oxidative Stress and Emergence of Psychosis

Treatment and prevention strategies for schizophrenia require knowledge about the mechanisms involved in the psychotic transition. Increasing evidence suggests a redox imbalance in schizophrenia patients. This narrative review presents an overview of the scientific literature regarding blood oxidative stress markers’ evolution in the early stages of psychosis and chronic patients. Studies investigating peripheral levels of oxidative stress in schizophrenia patients, first episode of psychosis or UHR individuals were considered. A total of 76 peer-reviewed articles published from 1991 to 2022 on PubMed and EMBASE were included. Schizophrenia patients present with increased levels of oxidative damage to lipids in the blood, and decreased levels of non-enzymatic antioxidants. Genetic studies provide evidence for altered antioxidant functions in patients. Antioxidant blood levels are decreased before psychosis onset and blood levels of oxidative stress correlate with symptoms severity in patients. Finally, adjunct treatment of antipsychotics with the antioxidant N-acetyl cysteine appears to be effective in schizophrenia patients. Further studies are required to assess its efficacy as a prevention strategy. Redox imbalance might contribute to the pathophysiology of emerging psychosis and could serve as a therapeutic target for preventive or adjunctive therapies, as well as biomarkers of disease progression.

QT shortening: a proarrhythmic safety surrogate measure or an inappropriate indicator of it?

OBJECTIVE

To examine whether QT interval shortening is an overlooked adverse event as compared to QT prolongation through a review of preclinical, clinical and post-marketing adverse event data available to the regulator for centrally and nationally authorized medicinal products.

METHODS

Potential safety signals of QT shortening related to authorized medicinal products were detected from Eudravigilance using proportional reporting ratios. Active substances identified as having unexpected signals of QT shortening were assessed in depth using the Bradford-Hill criteria for causation. Preclinical, clinical and adverse event data related to each active substance was used in the assessments. Post marketing adverse event cases were reviewed for imputability using the French method.

RESULTS

80 adverse event cases of electrocardiogram QT shortening were detected from 13 different active substances which included antipsychotics and antiepileptics (Clozapine, Ziprasidone, Quetiapine, Olanzapine, Carbamazepine), cardiovascular drugs (Atenolol, Digoxin, Ramipril, Simvastatin), anti-inflammatories and analgesics (Ibuprofen, Paracetamol) and other substances Calcium Carbonate (Mineral Supplement/Antacid) and Fingolimod (Immunosuppressant). By comparison 404 active substances were found have a potential safety signal of Electrocardiogram QT prolongation. Following in depth review none of the 13 active substances identified were found to be clearly associated with QT shortening using the minimum level of evidence for regulatory action. In the preclinical data reviewed we observed cases of morphological changes to the action potential (AP) where the Action Potential Duration at 90% (APD₉₀) was not affected.

CONCLUSIONS

From a regulatory perspective one cannot refute the possibility of a clinically relevant risk from QT shortening through the current testing requirements. Lack of further investigations into any potential morphological changes to the AP, or APD₉₀ shortening beyond a specified threshold in our opinion does not fully exclude the possibility of proarrhythmic effects of active substances.

Treating Negative Symptoms in Schizophrenia: an Update

Interest in the negative symptoms of schizophrenia has increased rapidly over the last several decades, paralleling a growing interest in functional, in addition to clinical, recovery, and evidence underscoring the importance negative symptoms play in the former. Efforts continue to better define and measure negative symptoms, distinguish their impact from that of other symptom domains, and establish effective treatments as well as trials to assess these. Multiple interventions have been the subject of investigation, to date, including numerous pharmacological strategies, brain stimulation, and non-somatic approaches. Level and quality of evidence vary considerably, but to this point, no specific treatment can be recommended. This is particularly problematic for individuals burdened with negative symptoms in the face of mild or absent positive symptoms. Presently, clinicians will sometimes turn to interventions that are seen as more “benign” and in line with routine clinical practice. Strategies include use of atypical antipsychotics, ensuring the lowest possible antipsychotic dose that maintains control of positive symptoms (this can involve a shift from antipsychotic polypharmacy to monotherapy), possibly an antidepressant trial (given diagnostic uncertainty and the frequent use of these drugs in schizophrenia), and non-somatic interventions (e.g., cognitive behavioral therapy, CBT). The array and diversity of strategies currently under investigation highlight the lack of evidence-based treatments and our limited understanding regarding negative symptoms underlying etiology and pathophysiology. Their onset, which can precede the first psychotic break, also means that treatments are delayed. From this perspective, identification of biomarkers and/or endophenotypes permitting earlier diagnosis and intervention may serve to improve treatment efficacy as well as outcomes.