Combined treatment of myo-inositol and d-chiro-inositol (80:1) as a therapeutic approach to restore inositol eumetabolism in patients with bipolar disorder taking lithium and valproic acid.

Objective: Patients with bipolar disorder (BD) experience a poor quality of life (QoL) and a weak adherence to the therapy due to the various side effects occurring during the pharmacological therapy. To date clinicians have no tools to intervene on such effects, considering them as an unavoidable part of the therapy. This review paves the way for a step forward in the management of patients with BD bridging the therapeutic gap in clinical practice.
Materials and Methods: We reviewed the literature, searching through different databases (MEDLINE, Scopus, Google Scholar). We used different keywords, including bipolar disorder, lithium and valproic acid, inositol role in bipolar disorder, side effects, inositol depletion, supplementation of inositols under lithium treatment, inositol role in metabolism, hypothyroidism, renal and cardiac functionality. In particular, we narrowed the search down to English literature, excluding works before 1980s. Regarding clinical studies, we included case reports and both preclinical and clinical studies, especially only those exhibiting a control group. The outcome of the database search was to highlight the threat of side effects and the relationship with inositol lower levels, paving the way for a step forward in the management of patients with BD.
Results: Based on the collected evidence, the combined administration of myo-inositol (myo-ins) and d-chiro-inositol (d-chiro-ins) is strongly recommended in order to restore levels and metabolism of inositols. Previous studies pointed out the beneficial effects of inositols in recovering pathological conditions, like polycystic ovary syndrome (PCOS), hypothyroidism, weight gain, cardiac functionality, being all these conditions related to the depletion of inositols. Furthermore, a controlled dosage of inositols, up to 6 grams/daily, may reduce the side effects caused by lithium therapy, without hindering its central therapeutic role on patients' mood.
Conclusions: Considering the iatrogenic depletion of inositols, the tailored ratio 80:1 in favour of myo-ins, may become a safe and effective strategy to counteract side effects, by providing a large amount of myo-ins and an adequate one of d-chiro-ins. The clinical dosage of inositols used as dietary supplementation is 4 grams/daily, and it may allow the recovery of the side effects and improve patients' QoL, without reducing the central therapeutic effect of the pharmacological therapy.