Pharmacokinetics and Efficacy of Fluvoxamine and Amitriptyline in Depression

Optimising Fluvoxamine Maternal/Fetal Exposure during Gestation: A Pharmacokinetic Virtual Clinical Trials Study

Fluvoxamine plasma concentrations have been shown to decrease throughout pregnancy. CYP2D6 polymorphisms significantly influence these changes. However, knowledge of an optimum dose adjustment according to the CYP2D6 phenotype is still limited. This study implemented a physiologically based pharmacokinetic modelling approach to assess the gestational changes in fluvoxamine maternal and umbilical cord concentrations. The optimal dosing strategies during pregnancy were simulated, and the impact of CYP2D6 phenotypes on fluvoxamine maternal and fetal concentrations was considered. A significant decrease in fluvoxamine maternal plasma concentrations was noted during gestation. As for the fetal concentration, a substantial increase was noted for the poor metabolisers (PM), with a constant level in the ultrarapid (UM) and extensive (EM) metabolisers commencing from gestation week 20 to term. The optimum dosing regimen suggested for UM and EM reached a maximum dose of 300 mg daily at gestational weeks (GW) 15 and 35, respectively. In contrast, a stable dose of 100 mg daily throughout gestation for the PM is sufficient to maintain the fluvoxamine plasma concentration within the therapeutic window (60-230 ng/mL). Dose adjustment during pregnancy is required for fluvoxamine, particularly for UM and EM, to maintain efficacy throughout the gestational period.

Combining Antidepressants vs Antidepressant Monotherapy for Treatment of Patients With Acute Depression: A Systematic Review and Meta-analysis

IMPORTANCE

Combining antidepressants is frequently done in the treatment of acute depression, but studies have yielded conflicting results.

OBJECTIVE

To conduct a systematic review and meta-analysis assessing efficacy and tolerability of combination therapy. Combinations using presynaptic α2-autoreceptor antagonists or bupropion were investigated separately.

DATA SOURCES

MEDLINE, Embase, PsycINFO, and the Cochrane Central Register of Controlled Trials were systematically searched from each database inception through January 2020.

STUDY SELECTION

Randomized clinical trials (RCTs) comparing combinations of antidepressants with antidepressant monotherapy in adult patients with acute depression were included.

DATA EXTRACTION AND SYNTHESIS

Following guidelines from Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and recommendations from the Cochrane Handbook, 2 reviewers independently performed a literature search, study selection, data extraction, and evaluation of risk of bias. Data were pooled in random-effects analyses.

MAIN OUTCOMES AND MEASURES

Primary outcome was efficacy measured as standardized mean difference (SMD); secondary outcomes were response, remission, change from baseline in rating scale scores, number of dropouts, and number of dropouts due to adverse events.

RESULTS

Thirty-nine RCTs including 6751 patients were eligible. Combination treatment was statistically significantly associated with superior treatment outcomes relative to monotherapy (SMD = 0.31; 95% CI, 0.19-0.44). Combining a reuptake inhibitor with an antagonist of presynaptic α2-autoreceptors was superior to other combinations (SMD = 0.37; 95% CI, 0.19-0.55). Bupropion combinations were not superior to monotherapy (SMD = 0.10; 95% CI, -0.07 to 0.27). Numbers of dropouts and dropouts due to adverse events did not differ between treatments. Studies were heterogeneous, and there was indication of publication bias (Egger test result was positive; P = .007, df = 36), but results remained robust across prespecified secondary outcomes and sensitivity and subgroup analyses, including analyses restricted to studies with low risk of bias.

CONCLUSIONS AND RELEVANCE

In this meta-analysis of RCTs comparing combinations of antidepressants with antidepressant monotherapy, combining antidepressants was associated with superior treatment outcomes but not with more patients dropping out of treatment. Combinations using an antagonist of presynaptic α2-autoreceptors may be preferable and may be applied as a first-line treatment in severe cases of depression and for patients considered nonresponders.

The Antidepressant and Cognitive Improvement Activities of the Traditional Chinese Herb Cistanche

More than ten percent of people suffer from at least one episode of depression and related mental disorders in a lifetime, and depression and related mental disorders are one of the world's greatest public health problems. A multiple system theory holds that dysregulation of the multiple systems underlies the pathogenesis of depression and related mental disorders, and new therapies based on the multiple system dysregulation theory are urgently needed. In this study, the antidepressant effect of decoction from herb Cistanche deserticola Y.C.Ma and Cistanche tubulosa was examined. Herb Cistanche decoction reduced the immobility period significantly in the mouse tail suspension test. Mice treated with herb decoction showed an improved ability of spatial learning and memory in the Morris water maze test. Groups treated herb decoction displayed a downregulated monoamine oxidase (MAO) activity; the dopamine (DA) concentration in the brain was upregulated, indicating herb Cistanche decoction improved the nerve excitability; the serum concentration of corticosterone (CORT) was downregulated, showing that mice benefited from a reduced stress level. Hence, the antidepressant efficacy and mechanism of traditional Chinese herb Cistanche were explored in this study. Herb Cistanche showed a potential to be developed as a complementary and alternative therapy for depression.

Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine

In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.

Limitations of the Anticholinergic Activity Assay and Assay-Based Anticholinergic Drug Scales

OBJECTIVE

The anticholinergic activity (AA) assay is a common method to determine a patient's anticholinergic load. Several limitations, however, are expected when applying the AA assay to patients or using drug scales to estimate anticholinergic burden based on AA levels. This study aims to demonstrate common pitfalls in an experimental setting and outline their clinical consequences.

METHODS

The AA was analyzed for five drugs with reported interaction with muscarinic receptors. Concentration-response curves were constructed for furosemide (weak anticholinergic), diphenhydramine (moderate anticholinergic), the strong anticholinergic amitriptyline and its metabolite nortriptyline, and the cholinergic pilocarpine. The Combination Index (CI) was used to assess the interaction of three drug combinations with amitriptyline.

RESULTS

All compounds displaced the radioactive tracer from its receptor binding site in a concentration-dependent manner, and full displacement was reached for all compounds except furosemide (E_max 16%). The CI indicated that amitriptyline and thioridazine have antagonistic effects (CI = 1.46) at low and synergistic effects (CI = 0.88) at higher concentrations (p < 0.0001), whereas synergistic effects (CI = 0.47-0.48) were observed for amitriptyline in any concentration combined with pilocarpine (p < 0.001).

CONCLUSION

When the patient's anticholinergic load is estimated using AA levels, the actual exposure, combination of anticholinergic drugs, their active metabolites, and also drugs with an opposite pharmacologic action will contribute to AA levels, whereas weak anticholinergic drugs in therapeutic concentrations are rather negligible.

Combining Antidepressants in Acute Treatment of Depression: A Meta-Analysis of 38 Studies Including 4511 Patients

OBJECTIVE

Combining antidepressants (ADs) for therapy of acute depression is frequently employed, but randomized studies have yielded conflicting results. We conducted a systematic review and meta-analysis aimed at determining efficacy and tolerability of combination therapy.

METHODS

MEDLINE, Embase, PsycINFO, and CENTRAL databases were systematically searched through March 2014 for controlled studies comparing combinations of ADs with AD monotherapy in adult patients suffering from acute depression. The prespecified primary outcome was standardized mean difference (SMD), secondary outcomes were response, remission, and dropouts.

RESULTS

Among 8688 articles screened, 38 studies were eligible, including 4511 patients. Combination treatment was statistically, significantly superior to monotherapy (SMD 0.29; 95% CI 0.16 to 0.42). During monotherapy, slightly fewer patients dropped out due to adverse events (OR 0.90; 95% CI 0.53 to 1.53). Studies were heterogeneous (I(2) = 63%), and there was indication of moderate publication bias (fail-safe N for an effect of 0.1:44), but results remained robust across prespecified secondary outcomes and subgroups, including analyses restricted to randomized controlled trials and low risk of bias studies. Meta-regression revealed an association of SMD with difference in imipramine-equivalent dose. Combining a reuptake inhibitor with an antagonist of presynaptic α2-autoreceptors was superior to other combinations.

CONCLUSION

Combining ADs seems to be superior to monotherapy with only slightly more patients dropping out. Combining a reuptake inhibitor with an antagonist of presynaptic α2-autoreceptors seems to be significantly more effective than other combinations. Overall, our search revealed a dearth of well-designed studies.

Safety and tolerability of antidepressant co-treatment in acute major depressive disorder: results from a systematic review and exploratory meta-analysis

INTRODUCTION

Although antidepressant (AD) monotherapy is recommended first-line for major depressive disorder (MDD), AD + AD co-treatment is common.

AREAS COVERED

We conducted the first systematic review searching PubMed/MEDLINE/PsycInfo/Embase from database inception until 1 June 2015 for acute randomized trials in ≥ 20 adults with MDD comparing AD monotherapy with AD + AD co-treatment that reported quantitative data on adverse events (AEs). Meta-analyzing 23 studies (n = 2435, duration = 6.6 weeks) AD monotherapy and AD + AD co-treatment were similar regarding intolerability-related discontinuation (risk ratio [RR] = 1.38, 95% CI = 0.89 - 1.10) and frequency of ≥ 1 AE (RR = 1.19, 95% CI = 0.95 - 1.49). Nevertheless, AD + AD co-treatment was associated with significantly greater burden regarding 4/25 AEs (tremor: RR = 1.55, 95% CI = 1.01 - 2.38; sweating: RR = 1.95, 95% CI = 1.13 -3.38, ≥ 7% weight gain: RR = 3.15, 95% CI = 1.34 - 7.41; weight gain = 2.17, 95% CI = 0.71 - 3.63 kg), but not more CNS, gastrointestinal, sexual or alertness-related AEs. However, 11/25 AEs (44.0%) were reported in only 1 - 2 studies. Adding noradrenergic and specific serotonergic antidepressants (NaSSA) or tricyclic antidepressants (TCA) to selective serotonin reuptake inhibitors (SSRIs) was specifically associated with more AEs.

EXPERT OPINION

The potential for increased AEs with AD + AD co-treatment needs to be considered vis-à-vis unclear efficacy benefits of this strategy. In particular, NaSSAs and TCAs should be added to SSRIs with caution. Clearly, more data on side-effect burden of AD + AD co-treatment are needed.

Antidepressant combination for major depression in incomplete responders--a systematic review

BACKGROUND

Antidepressant combination has been suggested as a strategy to increase treatment efficacy. The objective of this study was to perform a systematic review and meta-analysis of studies that assessed the effect of antidepressant combination for major depression in patients with incomplete response to an initial antidepressant.

METHODS

Studies were retrieved from PubMed (1966-February, 2012), Cochrane Library (-February, 2012), Embase (1980-February, 2012), PsycINFO (1980-February, 2012), Lilacs (1982-February, 2012), clinical trials registry, thesis database (www.capes.gov.br), and secondary references. Included studies had an open label phase in which an initial antidepressant was used for the treatment of major depression and a double blind phase for the incomplete responders that compared monotherapy with the first antidepressant versus the association of a second antidepressant to the first one.

RESULTS

Out of the 4,884 studies retrieved, only five satisfied the inclusion criteria. The total number of patients included was 483. Only two small trials reported benefits of adding a second antidepressant to the initial antidepressant. Dropouts due to side effects were not reported in three studies. Meta-analysis was not performed due to the small number of studies, the inconsistency in the direction of effect and the possible instability of effect size. Only limited kinds of combination, involving mianserin, mirtazapine and desipramine were studied. Some properties of the first two drugs such as the anxiolytic, sedative, and orexigenic effects, can mimic depression improvement.

LIMITATIONS

Publication bias cannot be ruled out. Only one study included a monotherapy arm with the antidepressant used for augmentation of the first antidepressant.

CONCLUSIONS

The practice of using a combination of antidepressants for major depression in incomplete responders is not warranted by the literature.

Age-related changes in antidepressant pharmacokinetics and potential drug-drug interactions: a comparison of evidence-based literature and package insert information

BACKGROUND

Antidepressants are among the most commonly prescribed psychotropic agents for older patients. Little is known about the best source of pharmacotherapy information to consult about key factors necessary to safely prescribe these medications to older patients.

OBJECTIVE

The objective of this study was to synthesize and contrast information in the package insert (PI) with information found in the scientific literature about age-related changes of antidepressants in systemic clearance and potential pharmacokinetic drug-drug interactions (DDIs).

METHODS

A comprehensive search of two databases (MEDLINE and EMBASE from January 1, 1975 to September 30, 2011) with the use of a combination of search terms (antidepressants, pharmacokinetics, and drug interactions) was conducted to identify relevant English language articles. This information was independently reviewed by two researchers and synthesized into tables. These same two researchers examined the most up-to-date PIs for the 26 agents available at the time of the study to abstract quantitative information about age-related decline in systemic clearance and potential DDIs. The agreement between the two information sources was tested with κ statistics.

RESULTS

The literature reported age-related clearance changes for 13 antidepressants, whereas the PIs only had evidence about 4 antidepressants (κ < 0.4). Similarly, the literature identified 45 medications that could potentially interact with a specific antidepressant, whereas the PIs only provided evidence about 12 potential medication-antidepressant DDIs (κ < 0.4).

CONCLUSION

The evidence-based literature compared with PIs is the most complete pharmacotherapy information source about both age-related clearance changes and pharmacokinetic DDIs with antidepressants. Future rigorously designed observational studies are needed to examine the combined risk of antidepressants with age-related decline in clearance and potential DDIs on important health outcomes such as falls and fractures in older patients.