Serum concentrations of antidepressant drugs in a naturalistic setting: compilation based on a large therapeutic drug monitoring database

Antidepressant drugs in children and adolescents: analytical and demographic data in a naturalistic, clinical study

Pharmacokinetics of antidepressant drugs (ATDs), in terms of steady-state and trough values, in patients from Child and Adolescent Psychiatry centers in the midsouth-eastern part of Sweden, were evaluated, and the use of ATDs in this population were described. Patients to be prescribed an ATD were studied between 2002 and 2004. Two hundred eleven children, 64% girls and 36% boys (ages 8-20 years) were evaluated. The primary indication for the antidepressant treatment was depression in 69% of subjects. The median body mass index was 20.2 kg/m² (range, 12.4-38.6 kg/m²). Suspected adverse drug reactions were spontaneously reported in 31% (no serious). Monotherapy was indicated in 49% of request forms. The most common drug combination with the ATD was oral contraceptives. The concentrations of drugs in the patient evaluated population to referenced data for adults from the dose administered were as expected in 63%, higher than expected in 26% and lower than expected in 11%. The most prescribed ATD was sertraline (SERT). Dose-concentration relationships for SERT and metabolite desmethylsertraline (DSERT) were seen, rs = 0.48 and rs = 0.5, respectively. No relationship was found between dose and ratio DSERT/SERT. The median daily dose was 50 mg (range, 12.5-150 mg), SERT concentration 16 ng/mL (range, 3-88 ng/mL), and DSERT 33 ng/mL (range, 0-253 ng/mL). CYP2D6*4 was the most common poor metabolizer allele. Therapeutic drug monitoring may provide support to prescribing physicians to individual dose optimizing and to assess drug compliance, above all when ATDs are not well studied in pediatric patients before approval for general prescription.

Classification of drugs based on properties of sodium channel inhibition: a comparative automated patch-clamp study

Background

There is only one established drug binding site on sodium channels. However, drug binding of sodium channels shows extreme promiscuity: ∼25% of investigated drugs have been found to potently inhibit sodium channels. The structural diversity of these molecules suggests that they may not share the binding site, and/or the mode of action. Our goal was to attempt classification of sodium channel inhibitors by measuring multiple properties of inhibition in electrophysiology experiments. We also aimed to investigate if different properties of inhibition correlate with specific chemical properties of the compounds.

Methodology/Principal Findings

A comparative electrophysiological study of 35 compounds, including classic sodium channel inhibitors (anticonvulsants, antiarrhythmics and local anesthetics), as well as antidepressants, antipsychotics and neuroprotective agents, was carried out using rNav1.2 expressing HEK-293 cells and the QPatch automatic patch-clamp instrument. In the multi-dimensional space defined by the eight properties of inhibition (resting and inactivated affinity, potency, reversibility, time constants of onset and offset, use-dependence and state-dependence), at least three distinct types of inhibition could be identified; these probably reflect distinct modes of action. The compounds were clustered similarly in the multi-dimensional space defined by relevant chemical properties, including measures of lipophilicity, aromaticity, molecular size, polarity and electric charge. Drugs of the same therapeutic indication typically belonged to the same type. We identified chemical properties, which were important in determining specific properties of inhibition. State-dependence correlated with lipophilicity, the ratio of the neutral form of molecules, and aromaticity: We noticed that the highly state dependent inhibitors had at least two aromatic rings, logP>4.0, and pKa<8.0.

Conclusions/Significance

The correlations of inhibition properties both with chemical properties and therapeutic profiles would not have been evident through the sole determination of IC₅₀; therefore, recording multiple properties of inhibition may allow improved prediction of therapeutic usefulness.

Comparisons of the efficacy and tolerability of extended-release venlafaxine, mirtazapine, and paroxetine in treatment-resistant depression: a double-blind, randomized pilot study in a Chinese population

To compare the efficacy and tolerability of antidepressants switch with extended-release venlafaxine (venlafaxine-XR), mirtazapine, and paroxetine in Chinese patients with major depressive disorder who had 2 consecutive unsuccessful antidepressant trials. One hundred fifty adult patients with treatment-resistant depression according to their medical records and/or response to current treatments were randomly assigned to receive fixed-dosage treatment of venlafaxine-XR 225 mg/d (n = 50), mirtazapine 45 mg/d (n = 55), or paroxetine 20 mg/d (n = 45) for 8 weeks. The primary outcome was the remission rates that were defined as a score 7 or lower on the 17-item Hamilton Rating Scale for Depression (HRSD-17). Secondary outcomes included the remission rate defined by the Self-Rating Depression Scale of 50 or lower and the response rate defined by a 50% reduction or greater on the HRSD-17 total score, and the improvement of patients' general health functions. The completion rates were 82% for venlafaxine-XR, 81.8% for mirtazapine, and 82.2% for paroxetine. Only one patient in paroxetine arm discontinued the study owing to an adverse event. The remission rates based on the HRSD-17 were 42.0% for venlafaxine-XR, 36.4% for mirtazapine, and 46.7% for paroxetine. There were no statistical significances between treatment arms in remission rates. Similarly, there were also no significant differences between groups in secondary outcome measure. Venlafaxine-XR, mirtazapine, and paroxetine were equally effective in the treatment of Chinese patients with major depressive disorder who failed at least 2 previous antidepressant treatments. Selecting any of these 3 antidepressants as a third-step antidepressant is a reasonable choice for this group of patients.

Fluoxetine and citalopram exhibit potent antiinflammatory activity in human and murine models of rheumatoid arthritis and inhibit toll-like receptors

OBJECTIVE

Selective serotonin reuptake inhibitors (SSRIs), in addition to their antidepressant effects, have been reported to have antiinflammatory effects. The aim of this study was to assess the antiarthritic potential of 2 SSRIs, fluoxetine and citalopram, in murine collagen-induced arthritis (CIA) and in a human ex vivo disease model of rheumatoid arthritis (RA).

METHODS

Following therapeutic administration of SSRIs, paw swelling was assessed and clinical scores were determined daily in DBA/1 mice with CIA. Joint architecture was examined histologically at the end of the treatment period. Cultures of human RA synovial membranes were treated with SSRIs, and cytokine production was measured. Toll-like receptor (TLR) function was examined in murine and human macrophages, human B cells, and human fibroblast-like synovial cells treated with SSRIs.

RESULTS

Both SSRIs significantly inhibited disease progression in mice with CIA, with fluoxetine showing the greatest degree of efficacy at the clinical and histologic levels. In addition, both drugs significantly inhibited the spontaneous production of tumor necrosis factor, interleukin-6, and interferon-gamma-inducible protein 10 in human RA synovial membrane cultures. Fluoxetine and citalopram treatment also inhibited the signaling of TLRs 3, 7, 8, and 9, providing a potential mechanism for their antiinflammatory action.

CONCLUSION

Fluoxetine and citalopram treatment selectively inhibit endosomal TLR signaling, ameliorate disease in CIA, and suppress inflammatory cytokine production in human RA tissue. These data highlight the antiarthritic potential of the SSRI drug family and provide further evidence of the involvement of TLRs in the pathogenesis of RA. The SSRIs may provide a template for potential antiarthritic drug development.