Pharmacogenomics of Lithium Response in Bipolar Disorder.

Despite being the most widely studied mood stabilizer, researchers have not confirmed a mechanism for lithium's therapeutic efficacy in Bipolar Disorder (BD). Pharmacogenomic applications may be clinically useful in the future for identifying lithium-responsive patients and facilitating personalized treatment. Six genome-wide association studies (GWAS) reviewed here present evidence of genetic variations related to lithium responsivity and side effect expression. Variants were found on genes regulating the glutamate system, including GAD-like gene 1 (GADL1) and GRIA2 gene, a mutually-regulated target of lithium. In addition, single nucleotide polymorphisms (SNPs) discovered on SESTD1 may account for lithium's exceptional ability to permeate cell membranes and mediate autoimmune and renal effects. Studies also corroborated the importance of epigenetics and stress regulation on lithium response, finding variants on long, non-coding RNA genes and associations between response and genetic loading for psychiatric comorbidities. Overall, the precision medicine model of stratifying patients based on phenotype seems to derive genotypic support of a separate clinical subtype of lithium-responsive BD. Results have yet to be expounded upon and should therefore be interpreted with caution.

Olanzapine-Induced Hyponatremia Presenting with Seizure Requiring Intensive Care Unit Admission.

Rapid-onset hyponatremia is a rare, but potential, complication of olanzapine treatment. Hyponatremia, secondary to atypical antipsychotic use, has been reported in many case reports and is thought to be associated with a syndrome of inappropriate anti-diuretic hormone secretion (SIADH). Psychogenic polydipsia is a separate cause of hyponatremia, which is also seen in the psychiatric population, particularly in schizophrenia, and must be differentiated from SIADH. We report a case of sudden-onset hyponatremia resulting in seizure onset necessitating intensive care unit admission in a patient taking olanzapine during hospitalization in a psychiatric unit. Clinicians should be aware of the association between olanzapine and hyponatremia secondary to SIADH or psychogenic polydipsia. As in our case, the patient status may decline rapidly, resulting in seizure onset. Physicians should actively monitor patients taking antipsychotics for changes in serum sodium levels.

Delay of alternative antiviral therapy and poor outcomes of acyclovir-resistant herpes simplex virus infections in recipients of allogeneic stem cell transplant - a retrospective study.

Acyclovir is commonly used to prevent and treat herpes simplex virus (HSV) reactivation after hematopoietic cell transplant (HCT), and only few reports have been published on acyclovir-resistant HSV in HCT recipients. We reviewed the medical records of patients with a microbiologic diagnosis of acyclovir-resistant HSV by plaque reduction test who received an HCT from 2002 through 2014. A total of 4 028 HCTs were performed during the study period, and 18 of the recipients met the diagnostic criteria for acyclovir-resistant HSV. All cases had undergone allogeneic HCTs. Most patients were in the pre-engraftment period or on systemic corticosteroid therapy for graft-versus-host disease (GVHD). The median time between diagnosis and susceptibility testing was 15 days, and antiviral therapy was changed at a median of 27 days. Patients required prolonged therapy (~80 days), and many had serious complications including renal failure and hospitalization. In conclusion, acyclovir-resistant HSV infection is more likely during the period of profound deficit in T-cell-mediated immunity and is associated with significant morbidities. Higher doses of acyclovir prophylaxis might be needed for patients with history of HSV during pre-engraftment or GVHD treatment. In patients who do not respond or progress after 1 week of acyclovir therapy, testing for drug-resistant HSV, and early switch to an alternative antiviral should be considered.