Levomilnacipran Pharmacokinetics in Healthy Volunteers Versus Patients with Major Depressive Disorder and Implications for Norepinephrine and Serotonin Reuptake Inhibition

Systemic and Brain Pharmacokinetics of Milnacipran in Mice: Comparison of Intraperitoneal and Intravenous Administration

Milnacipran is a dual serotonin and norepinephrine reuptake inhibitor, clinically used for the treatment of major depression or fibromyalgia. Currently, there are no studies reporting the pharmacokinetics (PK) of milnacipran after intraperitoneal (IP) injection, despite this being the primary administration route in numerous experimental studies using the drug. Therefore, the present study was designed to investigate the PK profile of IP-administered milnacipran in mice and compare it to the intravenous (IV) route. First a liquid chromatography-mass spectrometry (LC-MS/MS) method was developed and validated to accurately quantify milnacipran in biological samples. The method was used to quantify milnacipran in blood and brain samples collected at various time-points post-administration. Non-compartmental and PK analyses were employed to determine key PK parameters. The maximum concentration (Cmax) of the drug in plasma was at 5 min after IP administration, whereas in the brain, it was at 60 min for both routes of administration. Curiously, the majority of PK parameters were similar irrespective of the administration route, and the bioavailability was 92.5% after the IP injection. These findings provide insight into milnacipran's absorption, distribution, and elimination characteristics in mice after IP administration for the first time and should be valuable for future pharmacological studies.

Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants

Objectives: More than 40 drugs are available to treat affective disorders. Individual selection of the optimal drug and dose is required to attain the highest possible efficacy and acceptable tolerability for every patient.Methods: This review, which includes more than 500 articles selected by 30 experts, combines relevant knowledge on studies investigating the pharmacokinetics, pharmacodynamics and pharmacogenetics of 33 antidepressant drugs and of 4 drugs approved for augmentation in cases of insufficient response to antidepressant monotherapy. Such studies typically measure drug concentrations in blood (i.e. therapeutic drug monitoring) and genotype relevant genetic polymorphisms of enzymes, transporters or receptors involved in drug metabolism or mechanism of action. Imaging studies, primarily positron emission tomography that relates drug concentrations in blood and radioligand binding, are considered to quantify target structure occupancy by the antidepressant drugs in vivo. Results: Evidence is given that in vivo imaging, therapeutic drug monitoring and genotyping and/or phenotyping of drug metabolising enzymes should be an integral part in the development of any new antidepressant drug.Conclusions: To guide antidepressant drug therapy in everyday practice, there are multiple indications such as uncertain adherence, polypharmacy, nonresponse and/or adverse reactions under therapeutically recommended doses, where therapeutic drug monitoring and cytochrome P450 genotyping and/or phenotyping should be applied as valid tools of precision medicine.

A Review of Novel Antidepressants: A Guide for Clinicians

This review article aims to provide insight into the mechanisms of action, pharmacokinetics, clinical efficacy, safety and tolerability of four novel antidepressants including desvenlafaxine, vortioxetine, vilazodone, and levomilnacipran. Following keywords are used in PubMed and Scopus to search for relevant articles: (depression) AND (psychopharmacology OR desvenlafaxine OR levomilnacipran OR vortioxetine OR vilazodone). Patients with a lack of effectiveness or tolerability to certain antidepressants may get benefit from selecting a new antidepressant with different mechanism of action. These medications can be an option in the selection of newer antidepressants. Depression may not be caused by the simple deficiency of serotonin in the brain, but rather a complex interplay of various neurotransmitters including serotonin, norepinephrine, glutamate, and histamine at certain brain areas. The above-mentioned novel antidepressants exert their therapeutic benefits by acting on multiple neurotransmitters. The complexity of underlying the neurobiological mechanism should be considered while formulating a plan of care.

A review of antidepressant-induced urinary hesitancy: a focus on levomilnacipran ER including two case presentations(5633)

INTRODUCTION

Levomilnacipran ER was recently FDA approved as Fetzima® for the treatment of MDD. Urinary hesitancy can be an adverse event associated with levomilnacipran treatment.

AREAS COVERED

This manuscript details the longitudinal course of levomilnacipran-induced urinary hesitancy in 2 cases that were in a pivotal clinical trial, examining possible predisposing factors and treatment issues. This manuscript also reviews the literature comparing urinary hesitancy associated with levomilnacipran versus other antidepressants. Antidepressants that are potent norepinephrine reuptake inhibitors like levomilnacipran, may have increased rates of associated urinary hesitancy. The latter can cause significant discomfort and a compromised quality of life. Occasionally, it can progress to urinary retention necessitating an emergency medical intervention.

EXPERT OPINION

All patients being treated with antidepressants should be carefully monitored for this side effect. Discontinuation of treatment or reduction of the dose of antidepressant frequently relieves urinary hesitancy; alternatively, treatment with an alpha1A antagonist, e.g., tamsulosin may relieve antidepressant-induced urinary hesitancy within hours to days; such strategies allow for continued antidepressant treatment without urinary hesitancy recurring. Thus, with appropriate clinical care, the benefits using levomilnacipran outweigh its risks.