Lithium augmentation of venlafaxine: an open-label trial

Venlafaxine's therapeutic reference range in the treatment of depression revised: a systematic review and meta-analysis

INTRODUCTION

The selective serotonin and norepinephrine reuptake inhibitor venlafaxine is among the most prescribed antidepressant drugs worldwide and, according to guidelines, its dose titration should be guided by drug-level monitoring of its active moiety (AM) which consists of venlafaxine (VEN) plus active metabolite O-desmethylvenlafaxine (ODV). This indication of therapeutic drug monitoring (TDM), however, assumes a clear concentration/effect relationship for a drug, which for VEN has not been systematically explored yet.

OBJECTIVES

We performed a systematic review and meta-analysis to investigate the relationship between blood levels, efficacy, and adverse reactions in order to suggest an optimal target concentration range for VEN oral formulations for the treatment of depression.

METHODS

Four databases (MEDLINE (PubMed), PsycINFO, Web of Science Core Collection, and Cochrane Library) were systematically searched in March 2022 for relevant articles according to a previously published protocol. Reviewers independently screened references and performed data extraction and critical appraisal.

RESULTS

High-quality randomized controlled trials investigating concentration/efficacy relationships and studies using a placebo lead-in phase were not found. Sixty-eight articles, consisting mostly of naturalistic TDM studies or small noncontrolled studies, met the eligibility criteria. Of them, five cohort studies reported a positive correlation between blood levels and antidepressant effects after VEN treatment. Our meta-analyses showed (i) higher AM and (ii) higher ODV concentrations in patients responding to VEN treatment when compared to non-responders (n = 360, k = 5). AM concentration-dependent occurrence of tremor was reported in one study. We found a linear relationship between daily dose and AM concentration within guideline recommended doses (75-225 mg/day). The population-based concentration ranges (25-75% interquartile) among 11 studies (n = 3200) using flexible dosing were (i) 225-450 ng/ml for the AM and (ii) 144-302 ng/ml for ODV. One PET study reported an occupancy of 80% serotonin transporters for ODV serum levels above 85 ng/ml. Based on our findings, we propose a therapeutic reference range for AM of 140-600 ng/ml.

CONCLUSION

VEN TDM within a range of 140 to 600 ng/ml (AM) will increase the probability of response in nonresponders. A titration within the proposed reference range is recommended in case of non-response at lower drug concentrations as a consequence of VEN's dual mechanism of action via combined serotonin and norepinephrine reuptake inhibition. Drug titration towards higher concentrations will, however, increase the risk for ADRs, in particular with supratherapeutic drug concentrations.

Augmentative Pharmacological Strategies in Treatment-Resistant Major Depression: A Comprehensive Review

Treatment resistant depression (TRD) is associated with poor outcomes, but a consensus is lacking in the literature regarding which compound represents the best pharmacological augmentation strategy to antidepressants (AD). In the present review, we identify the available literature regarding the pharmacological augmentation to AD in TRD. Research in the main psychiatric databases was performed (PubMed, ISI Web of Knowledge, PsychInfo). Only original articles in English with the main topic being pharmacological augmentation in TRD and presenting a precise definition of TRD were included. Aripiprazole and lithium were the most investigated molecules, and aripiprazole presented the strongest evidence of efficacy. Moreover, olanzapine, quetiapine, cariprazine, risperidone, and ziprasidone showed positive results but to a lesser extent. Brexpiprazole and intranasal esketamine need further study in real-world practice. Intravenous ketamine presented an evincible AD effect in the short-term. The efficacy of adjunctive ADs, antiepileptic drugs, psychostimulants, pramipexole, ropinirole, acetyl-salicylic acid, metyrapone, reserpine, testosterone, T3/T4, naltrexone, SAMe, and zinc cannot be precisely estimated in light of the limited available data. Studies on lamotrigine and pindolol reported negative results. According to our results, aripiprazole and lithium may be considered by clinicians as potential effective augmentative strategies in TRD, although the data regarding lithium are somewhat controversial. Reliable conclusions about the other molecules cannot be drawn. Further controlled comparative studies, standardized in terms of design, doses, and duration of the augmentative treatments, are needed to formulate definitive conclusions.

A randomized clinical trial comparing two two-phase treatment strategies for in-patients with severe depression

OBJECTIVE

To compare the efficacy of two antidepressant treatment strategies in severely depressed in-patients, that is, imipramine vs. venlafaxine, both with subsequent lithium addition in non-responders.

METHOD

In-patients (n = 88) with major depressive disorder were randomized to 7-week treatment with imipramine or venlafaxine (phase I). All non-responders (n = 44) received 4-week plasma level-targeted dose lithium addition (phase II). Efficacy was evaluated after 11 weeks of treatment.

RESULTS

Analyzing phases I and II combined, non-inferiority was established and the difference in the proportion of responders (HAM-D score reduction ≥50%) by the end of phase II demonstrated the venlafaxine-lithium treatment strategy to be significantly superior to the imipramine-lithium treatment strategy (77% vs. 52%) (χ² (1) = 6.03; P = 0.01). Regarding remission (HAM-D score ≤ 7), 15 of 44 (34%) patients in the imipramine-lithium treatment group were remitters compared to 22 of 44 (50%) patients in the venlafaxine-lithium treatment group, a non-significant difference. Patients in the venlafaxine-lithium treatment group had a non-significant larger mean HAM-D score reduction compared with patients in the imipramine-lithium treatment group (16.1 vs. 13.5 points, respectively; Cohen's d = 0.30).

CONCLUSION

The venlafaxine-lithium treatment strategy can be considered a valuable alternative for the imipramine-lithium treatment strategy in the treatment of severely depressed in-patients.

Challenging Treatment-Resistant Major Depressive Disorder: A Roadmap for Improved Therapeutics

Major depressive disorder (MDD) is associated with a significant burden and costs to the society. As remission of depressive symptoms is achieved in only one-third of the MDD patients after the first antidepressant trial, unsuccessful treatments contribute largely to the observed suffering and social costs of MDD. The present article provides a summary of the therapeutic strategies that have been tested for treatment-resistant depression (TRD). A computerized search on MedLine/PubMed database from 1975 to September 2014 was performed, using the keywords “treatment-resistant depression”, “major depressive disorder”, “adjunctive”, “refractory” and “augmentation”. From the 581 articles retrieved, two authors selected 79 papers. A manual searching further considered relevant articles of the reference lists. The evidence found supports adding or switching to another antidepressant from a different class is an effective strategy in more severe MDD after failure to an initial antidepressant trial. Also, in subjects resistant to two or more classes of antidepressants, some augmentation strategies and antidepressant combinations should be considered, although the overall response and remission rates are relatively low, except for fast acting glutamatergic modulators. The wide range of available treatments for TRD reflects the complexity of MDD, which does not underlie diverse key features of the disorder. Larger and well-designed studies applying dimensional approaches to measure efficacy and effectiveness are warranted.

Long-term efficacy of repeated daily prefrontal transcranial magnetic stimulation (TMS) in treatment-resistant depression

BACKGROUND

A few studies have examined the durability of transcranial magnetic stimulation (TMS) antidepressant benefit once patients remitted. This study examined the long-term durability of clinical benefit from TMS using a protocol-specified TMS taper and either continuation pharmacotherapy or naturalistic follow-up.

METHODS

Patients were remitters from an acute double-blind sham-controlled trial of TMS (n = 18), or from an open-label extension in patients who did not respond to the acute trial (n = 43). Long-term durability of TMS acute effect was examined in remitters over a 12-week follow-up. Relapse, defined as 24-item Hamilton Depression Rating Scale (HDRS-24) ≥20, was the primary outcome.

RESULTS

Of 61 remitters in the acute trial, five entered naturalistic follow-up and 50 entered the TMS taper. Thirty-two patients completed TMS taper and 1-, 2-, and 3-month follow-up. At 3-month visit, 29 of 50 (58%) were classified as in remission (HDRS-24 ≤10), two of 50 (4%) as partial responders (30%≤ HDRS-24 reduction <50% from baseline), and one of 50 (2%) met criteria for relapse. During the entire 3-month follow-up, five of the 37 patients relapsed (relapse rate = 13.5%), but four of them regained remission by the end of the study. The average time to relapse in these five patients was 7.2 ± 3.3 weeks. Patients who relapsed had higher depression scores at 1 month.

CONCLUSIONS

While one third of the sample was lost to follow-up, our results demonstrate that most patients contributing to observations experienced persistence of benefit from TMS followed by pharmacotherapy or no medication. Longer follow-up and more rigorous studies are needed to explore the true long-term durability of remission produced by TMS.

Therapeutic options for treatment-resistant depression

Treatment-resistant depression (TRD) presents major challenges for both patients and clinicians. There is no universally accepted definition of TRD, but results from the US National Institute of Mental Health's (NIMH) STAR*D (Sequenced Treatment Alternatives to Relieve Depression) programme indicate that after the failure of two treatment trials, the chances of remission decrease significantly. Several pharmacological and nonpharmacological treatments for TRD may be considered when optimized (adequate dose and duration) therapy has not produced a successful outcome and a patient is classified as resistant to treatment. Nonpharmacological strategies include psychotherapy (often in conjunction with pharmacotherapy), electroconvulsive therapy and vagus nerve stimulation. The US FDA recently approved vagus nerve stimulation as adjunctive therapy (after four prior treatment failures); however, its benefits are seen only after prolonged (up to 1 year) use. Other nonpharmacological options, such as repetitive transcranial stimulation, deep brain stimulation or psychosurgery, remain experimental and are not widely available. Pharmacological treatments of TRD can be grouped in two main categories: 'switching' or 'combining'. In the first, treatment is switched within and between classes of compounds. The benefits of switching include avoidance of polypharmacy, a narrower range of treatment-emergent adverse events and lower costs. An inherent disadvantage of any switching strategy is that partial treatment responses resulting from the initial treatment might be lost by its discontinuation in favour of another medication trial. Monotherapy switches have also been shown to have limited effectiveness in achieving remission. The advantage of combination strategies is the potential to build upon achieved improvements; they are generally recommended if partial response was achieved with the current treatment trial. Various non-antidepressant augmenting agents, such as lithium and thyroid hormones, are well studied, although not commonly used. There is also evidence of efficacy and increasing use of atypical antipsychotics in combination with antidepressants, for example, olanzapine in combination with fluoxetine (OFC) or augmentation with aripiprazole. The disadvantages of a combination strategy include multiple medications, a broader range of treatment-emergent adverse events and higher costs. Several experimental pharmaceutical treatment alternatives for TRD are also being explored in combination with antidepressants or as monotherapy. These less studied alternative compounds include pindolol, inositol, CNS stimulants, hormones, herbal supplements, omega-3 fatty acids, S-adenosyl-L-methionine, folic acid, lamotrigine, modafinil, riluzole and topiramate. In summary, despite an increasing variety of choices for the treatment of TRD, this condition remains universally undefined and represents an area of unmet medical need. There are few known approved pharmacological agents for TRD (aripiprazole and OFC) and overall outcomes remain poor. This might be an indication that depression itself is a heterogeneous condition with a great diversity of pathologies, highlighting the need for careful evaluation of individuals with depressive symptoms who are unresponsive to treatment. Clearly, more research is needed to provide clinicians with better guidance in making those treatment decisions--especially in light of accumulating evidence that the longer patients are unsuccessfully treated, the worse their long-term prognosis tends to be.

Combined treatment with reboxetine in depressed patients with no response to venlafaxine: a 6-week follow-up study

OBJECTIVE

The purpose of present study was to evaluate the efficacy of the addition of reboxetine in patients that had not previously responded, or had done so only partially, over 6 weeks of conventional pharmacological treatment with venlafaxine.

METHODS

This open-label, prospective and multicentric study included 40 outpatients diagnosed with major depressive disorder according to the DSM-IV criteria. Efficacy was assessed using the 21-item Hamilton Depression Rating Scale (HAMD) and the Clinical Global Impression-Improvement (CGI-I). Safety was evaluated by recording spontaneously reported adverse events. Data were analysed on an intent-to-treat basis, using the last-observation-carried-forward method.

RESULTS

Mean HAMD reduction was 34.9% (P < 0.0001). The percentages of responders (≥50% reduction in HAMD) and patients considered as benefiting from complete remission (HAMD ≤ 10 points) at week 6 were 27.5 and 12.5%, respectively. By the end of the treatment, the score of CGI-I decreased 24.8% (P < 0.0001). Percentage of patient improving (CGI < 4 points) was 47.5%. The most common non-serious adverse events were constipation, nervousness, anxiety and insomnia.

CONCLUSION

These findings suggest that the combined treatment of reboxetine and venlafaxine, in venlafaxine-resistant patients, may be an effective and well-tolerated strategy.

Lithium and venlafaxine interaction: a case of serotonin syndrome

Serotonin syndrome, which occurs as a result of enhanced serotonin concentration in the central nervous system, is a well-known adverse effect of serotonin-active medications. The concomitant use of antidepressant drugs associated with lithium as a co-adjuvant seems to increase the risk of this adverse reaction. We report a case of the serotonin syndrome during treatment with lithium and venlafaxine, an antidepressant with a dual selective re-uptake inhibition mechanism, and review the literature for similar cases. A 71-year-old woman developed serotonin syndrome while receiving treatment with moderate doses of lithium and venlafaxine for refractory depression. She had been taking higher doses of venlafaxine during the previous months with no significant secondary effects. Use of the Naranjo adverse drug reaction probability algorithm indicated a probable relationship between serotonin syndrome and treatment with lithium and venlafaxine.

A comparative meta-analysis of Clinical Global Impressions change in antidepressant trials

Two scales of the Clinical Global Impressions (CGI) Scale are frequently used in antidepressant trials. No research has systematically addressed how CGI change compares to change on established measures such as the Hamilton Depression Rating Scale (HAM-D), Montgomery-Asberg Depression Rating Scale, or Beck Depression Inventory. The current meta-analysis examined 75 antidepressant trials in which the CGI was used along with at least one other popular depression measure. The CGI-Severity scale was significantly more conservative than the HAM-D in rating change in double-blind trials, but not in open trials. The Beck Depression Inventory was significantly more conservative than the CGI-Severity. The CGI-Improvement scale was significantly more liberal than the HAM-D or Montgomery-Asberg Depression Rating Scale. Rater bias or scale content may explain differences between measures. Given the often substantial differences between instruments, researchers should use a variety of measures rather than relying on any single tool in assessing treatment response.

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.

Effect of milnacipran on extracellular monoamine concentrations in the medial prefrontal cortex of rats pre-treated with lithium

Antidepressants are effective in most patients with depression, but sometimes have sub-optimal effects. Thus, there is a need to use more powerful antidepressants when dealing with treatment-resistant cases. Lithium carbonate is widely used for this purpose. We investigated the acute effects of milnacipran, a serotonin-noradrenaline reuptake inhibitor, on extracellular serotonin, dopamine and noradrenaline concentrations, in the rat medial prefrontal cortex. The effects of milnacipran were examined in rats following 7 days of treatment with lithium, and in untreated controls. The lithium group had significantly greater basal levels of extracellular serotonin than the control group. Milnacipran (3 mg/kg) combined with lithium treatment caused a greater increase in extracellular noradrenaline and dopamine levels than milnacipran alone. Milnacipran (3 and 30 mg/kg) combined with lithium treatment also caused a greater increase in extracellular serotonin levels than milnacipran alone. Thus, lithium might augment the antidepressant effects of serotonin-noradrenaline reuptake inhibitors by augmenting serotonin release.

Combination therapy with venlafaxine and carbamazepine in depressive patients not responding to venlafaxine: pharmacokinetic and clinical aspects

The chiral antidepressant venlafaxine (VEN) is both a serotonin and a norepinephrine uptake inhibitor. CYP2D6 and CYP3A4 contribute to its metabolism, which has been shown to be stereoselective. Ten CYP2D6 genotyped and depressive (F32x and F33x, ICD-10) patients participated in an open study on the pharmacokinetic and pharmacodynamic consequences of a carbamazepine augmentation in VEN non-responders. After an initial 4-week treatment with VEN (195 +/- 52 mg/day), the only poor metabolizer out of 10 depressive patients had the highest plasma concentrations of S-VEN and R-VEN, respectively, whereas those of R-O-demethyl-VEN were lowest. Five non-responders completed the second 4-week study period, during which they were submitted to a combined VEN-carbamazepine treatment. In the only non-responder to this combined treatment, there was a dramatic decrease of both enantiomers of VEN, O-demethylvenlafaxine, N-desmethylvenlafaxine and N, O-didesmethylvenlafaxine in plasma, which suggests non-compliance, although metabolic induction by carbamazepine cannot entirely be excluded. The administration of carbamazepine [mean +/- SD, range: 360 +/- 89 (200-400) mg/day] over 4 weeks did not result in a significant modification of the plasma concentrations of the enantiomers of VEN and its O- and N-demethylated metabolites in the other patients. In conclusion, these preliminary observations suggest that the combination of VEN and carbamazepine represents an interesting augmentation strategy by its efficacy, tolerance and absence of pharmacokinetic modifications. However, these findings should be verified in a more comprehensive study.

Lithium augmentation in venlafaxine non-responders: an open study

Thirteen major depressive patients not responding to a 4-week venlafaxine 300 mg treatment were eligible for a 4-week open trial of lithium addition. Two patients had to stop lithium for a possible moderate serotonin syndrome and five patients became responders, including one dramatic response and two semi-rapid responses.

High-dose venlafaxine treatment in a depressed patient with a genetic CYP2D6 deficiency

A female patient (47 years) who suffered from a severe episode of a recurrent depression with psychotic symptoms (F33.3) firstly underwent several unsuccessful treatments. She was then submitted to a combined treatment with 2×300 mg/day extended-release venlafaxine (VEN) and lithium (0.7 mmol/l). She responded within 7 weeks and, after 9 weeks, she showed full remission. Moreover, she tolerated this medication well. Steady-state plasma concentrations of VEN and its metabolites and their enantiomers were measured. The concentrations of VEN and its metabolite O-demethyl-VEN (ODV) were 1024 and 234 ng/ml, respectively. The unusually high concentration of the parent compound in comparison to the metabolite is mainly explained by an impaired metabolism of R-VEN in this patient, who by genotyping was shown to have a genetic deficiency of CYP2D6. In conclusion, in patients suffering from non-response to an antidepressant treatment, an individualised treatment strategy should be developed, and stereoselective therapeutic drug monitoring and genotyping may be recommended.

Time course of clinical response to venlafaxine: relevance of plasma level and chirality

OBJECTIVE

Early clinical response to antidepressant treatment is an important therapeutic goal, considering the psychological, social and economic consequences of depression. The aim of the present study was to investigate the relationship between the time course of response and the concentration of venlafaxine (V), its active metabolite O-desmethylvenlafaxine (ODV) and enantiomeric ratios V(+)/V(-) and ODV(+)/ODV(-).

METHODS

Depressed inpatients ( n=35) received V orally at a fixed 300 mg daily dose. Accepted comedication included clorazepate (maximum 60 mg/day), zopiclone (maximum 15 mg/day) and low-dose trazodone (maximum 200 mg/day). Severity of depression was assessed on days 0, 4, 7, 11, 14, 21 and 28 (Montgomery and Asberg Depression Rating Scale). Blood samples were taken on day 14 and day 28 and submitted to stereoselective determination. All measurements reflected trough steady-state values. First, pattern analysis was used to provide a categorical perspective of clinical response (50% improvement from baseline depression score). Patients displaying non-response, transient response, early persistent response and delayed persistent response were compared with respect to racemic concentrations and enantiomeric ratios. Second, in a dimensional perspective, mixed-effects modelling was used to analyse severity of depression versus time curves with respect to the possible influence of concentrations and enantiomeric ratios.

RESULTS

Comparison of patients with and without persistent response did not reveal any significant difference for V, ODV, V+ODV plasma levels or enantiomeric ratios. Persistent response was significantly associated with less frequent pre-study antidepressant medication and less frequent comedication with zopiclone (day 14) and clorazepate (day 28) during the study. Focus on patients with persistent response ( n=19, 54.3%) indicated that early response, first observed before day 14, was associated with significantly higher V+ODV concentration than delayed response (median 725 ng/ml versus 554 ng/ml, P=0.023). No difference was found for pre-study medication or comedication during the study. Shorter time to onset of response was significantly associated with lower V(+)/V(-) enantiomeric ratio (r(s)=0.48, P<0.05). Mixed-effects modelling of depression severity versus time curves in patients with persistent response confirmed that either higher V+ODV plasma level or lower V(+)/V(-) ratio were significantly associated with more rapid decrease of depression score (likelihood ratio tests, P=0.012 and P=0.046, respectively).

CONCLUSION

Considering its modest sample size, naturalistic design and limited observation period, the present study provided preliminary indication that earlier clinical response may occur with higher V+ODV plasma level, extending previous dose-response studies. The hypothesis was also raised that exposure to a more potent noradrenergic therapeutic moiety, as reflected by a lower V(+)/V(-) ratio, may be relevant to early improvement of depression.

Selective serotonin reuptake inhibitors combined with venlafaxine in depressed patients who had partial response to venlafaxine: four cases

One third of depressive patients show partial or no response to antidepressant treatment. With partial or nonresponders, treatment strategies are as follows: switching to another antidepressant, augmenting with other psychotropic agents, or combining antidepressants. There are no data in the literature about the positive effect of combining venlafaxine with selective serotonin reuptake inhibitors (SSRIs). In this report, the presented cases had been on at least two different classes of antidepressant medication (or combination of antidepressants) for an adequate time and dose. They showed only a partial response to high dose of venlafaxine but improved after the addition of an SSRI (sertraline, citalopram, or paroxetine) to venlafaxine. The combination treatment was well tolerated in all of the cases.

Lithium augmentation of nortriptyline for subjects resistant to multiple antidepressants

Lithium augmentation, the most studied augmentation strategy for depression, has not been evaluated in patients with a history of non-response to multiple antidepressants. The objective of this study was to assess the efficacy of lithium augmentation for patients with a history of treatment resistant depression who also failed a prospective trial of nortriptyline. We enrolled 92 subjects with treatment resistant depression. Treatment resistance was defined by at least one, but no more than five, adequate trials of antidepressants during the current episode. Subjects were treated with nortriptyline (NT) for 6 weeks. Those subjects who tolerated NT for 6 weeks and whose depression did not respond (n=35) were randomized to receive either lithium (n=18) or placebo (N=17) augmentation of nortriptyline for an additional 6 weeks. Response was defined as an equal to or greater than 50% decrease in HAM-D-17 scores. After 6 weeks of double-blind augmentation, 12.5 % of subjects responded to lithium and 20.0% to placebo. Our results revealed no significant difference between lithium and placebo augmentation. While lithium augmentation seems to be useful in depression refractory to a single medication in some studies, our data suggest limited usefulness of this option for patients refractory to multiple treatments. More definitive data await the outcome of the NIMH Sequential Treatment Alternatives to Relieve Depression (STAR*D) study.