Can we recommend mirtazapine and bupropion for patients at risk for bleeding?: A systematic review and meta-analysis

[Understanding and assessing the antidepressant drug-associated risk of bleeding]

Antidepressants, in particular selective serotonin reuptake inhibitors (SSRIs), are the most commonly prescribed psychopharmacological drug group. Thus, a precise knowledge of the expected adverse drug reactions is indispensable. The increased risk of bleeding events is well documented, especially in patients treated with SSRIs. However, many other antidepressant drug groups have also been implicated in increasing the risk of bleeding. In the following review, the thrombocytic serotonin system and the respective targets of the different antidepressants are explained. Subsequently, the available literature on bleeding under the respective antidepressant classes or individual substances is presented, using data from meta-analyses whenever possible. In addition to the risk of bleeding in general, individual bleeding entities are also considered, such as gastrointestinal and cerebral hemorrhages. Finally, the effects of other drugs that increase the risk of bleeding (i. e., nonsteroidal anti-inflammatory drugs, platelet aggregation inhibitors and anticoagulants) in combination with antidepressant drugs are discussed. The information presented here is meant to guide practitioner's decision making regarding an appropriate antidepressant pharmacotherapy based on the patient's individual risk constellation.

Drug-drug-interactions in patients with atrial fibrillation admitted to the emergency department

Introduction

Polypharmacy is a growing concern in healthcare systems. While available data on potential drug-drug interactions (pDDI) from emergency department (ED) patients is derived from heterogenous populations, this study specifically focused on patients with atrial fibrillation (AF). We hypothesized that patients with AF have similar comorbidities, receive similar drugs, and have similar pDDIs. The overarching aim was to highlight frequent pDDIs, providing practical guidance for treating healthcare professionals and consequently reduce the risk of adverse drug reactions.

Methods

Two hundred patients ≥18 years with AF, who received rate- or rhythm-controlling medication at the ED of the University Hospital Vienna, and who were on long-term medication before admission, were eligible. Long-term medication alone, as well as in combination with medication administered at the ED were analyzed for pDDIs using the Lexicomp® Drug interactions database.

Results

Within the long-term medication of patients', we identified 664 pDDIs. Drugs administered at the ED increased pDDIs more than 3-fold to 2085. Approximately, every fifth patient received a contraindicated drug combination (on average 0.24 per patient), while 70% received drug combinations for which therapy modifications are recommended (on average 1.59 per patient). The most frequently involved drugs included amiodarone, propofol, bisoprolol, enoxaparin, and acetylsalicylic acid. Increased risk of bleeding, QTc prolongation, and myopathy were among the most relevant potential consequences of these interactions.

Discussion

In conclusion, an optimization of medication would be advisable in almost every AF patient. Treating healthcare professionals should be cautious of drugs that increase bleeding risk, prolong QTc, or bear a risk for myopathy.

Depression and Suicide Risk Screening: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

Importance

Depression is common and associated with substantial burden. Suicide rates have increased over the past decade, and both suicide attempts and deaths have devastating effects on individuals and families.

Objective

To review the benefits and harms of screening and treatment for depression and suicide risk and the accuracy of instruments to detect these conditions among primary care patients.

Data Sources

MEDLINE, PsychINFO, Cochrane library through September 7, 2022; references of existing reviews; ongoing surveillance for relevant literature through November 25, 2022.

Study Selection

English-language studies of screening or treatment compared with control conditions, or test accuracy of screening instruments (for depression, instruments were selected a priori; for suicide risk, all were included). Existing systematic reviews were used for treatment and test accuracy for depression.

Data Extraction and Synthesis

One investigator abstracted data; a second checked accuracy. Two investigators independently rated study quality. Findings were synthesized qualitatively, including reporting of meta-analysis results from existing systematic reviews; meta-analyses were conducted on original research when evidence was sufficient.

Main Outcomes and Measures

Depression outcomes; suicidal ideation, attempts, and deaths; sensitivity and specificity of screening tools.

Results

For depression, 105 studies were included: 32 original studies (N=385 607) and 73 systematic reviews (including ≈2138 studies [N ≈ 9.8 million]). Depression screening interventions, many of which included additional components beyond screening, were associated with a lower prevalence of depression or clinically important depressive symptomatology after 6 to 12 months (pooled odds ratio, 0.60 [95% CI, 0.50-0.73]; reported in 8 randomized clinical trials [n=10 244]; I2 = 0%). Several instruments demonstrated adequate test accuracy (eg, for the 9-item Patient Health Questionnaire at a cutoff of 10 or greater, the pooled sensitivity was 0.85 [95% CI, 0.79-0.89] and specificity was 0.85 [95% CI, 0.82-0.88]; reported in 47 studies [n = 11 234]). A large body of evidence supported benefits of psychological and pharmacologic treatment of depression. A pooled estimate from trials used for US Food and Drug Administration approval suggested a very small increase in the absolute risk of a suicide attempt with second-generation antidepressants (odds ratio, 1.53 [95% CI, 1.09-2.15]; n = 40 857; 0.7% of antidepressant users had a suicide attempt vs 0.3% of placebo users; median follow-up, 8 weeks). Twenty-seven studies (n = 24 826) addressed suicide risk. One randomized clinical trial (n=443) of a suicide risk screening intervention found no difference in suicidal ideation after 2 weeks between primary care patients who were and were not screened for suicide risk. Three studies of suicide risk test accuracy were included; none included replication of any instrument. The included suicide prevention studies generally did not demonstrate an improvement over usual care, which typically included specialty mental health treatment.

Conclusions and Relevance

Evidence supported depression screening in primary care settings, including during pregnancy and postpartum. There are numerous important gaps in the evidence for suicide risk screening in primary care settings.

Selective Serotonin Reuptake Inhibitor (SSRI) Bleeding Risk: Considerations for the Consult-Liaison Psychiatrist

PURPOSE OF REVIEW

To present a clinically oriented review of selective serotonin reuptake inhibitor (SSRI)-related bleeding issues commonly addressed by consult-liaison psychiatrists.

RECENT FINDINGS

Concomitant medical, surgical, or hospital-based conditions exacerbate the risk of SSRI-related bleeding even though a review of the literature suggests it is only marginally elevated. Psychiatrists and other clinicians need to consider these conditions along with antidepressant benefits when answering the question: to start, hold, continue, or change the antidepressant? Where an evidence base is limited, mechanistic understanding may help consult-liaison psychiatrists navigate this terrain and collaborate with other medical specialties on responsible antidepressant management. Most often, the risk is cumulative; data are not directly applicable to complex clinical situations. This review incorporates a hematologic perspective and approach to bleeding risk assessment along with extant data on SSRI-induced bleeding risk ad specific medical conditions.

The use of serotonin reuptake inhibitors increases the risk of bleeding in patients with assist devices

Background

Bleedings are frequent and dreaded complications in heart failure patients with ventricular assist devices (VAD). Serotonin reuptake inhibitor (SRI) antidepressants are widely used to treat depression in these patients, though they are attributed an increased risk of bleeding due to their modification of hemostasis. Evidence on bleeding risk of VAD patients under SRI medication is scarce and limited. We therefore aimed to assess if SRI use is associated with an elevated bleeding risk in this particularly vulnerable population.

Methods

We analyzed the medical records of 92 VAD patients at the University Heart Center Zurich between September 2004 and April 2018 for the occurrence of bleedings and the concomitant use of an SRI. Bleeding was defined as any type of post-implantation bleeding requiring medical treatment. We performed univariate analyses and linear mixed-effects models, adjusting for baseline clinical characteristics as potential predictors to identify differences in bleeding rates in patients with vs. without SRI intake.

Results

The cohort comprised 60.9% of patients with a continuous-flow VAD and 39.1% with a pulsatile-flow VAD. A total of 77.2% of patients experienced at least one bleeding incident. Overall, 28.6% of bleedings occurred under SRI therapy. A generalized linear mixed model showed a predictive effect of SRI medication on bleeding rate, independent of VAD type (z = 2.091, p = 0.037).

Conclusions

Bleeding events in heart failure patients occur frequently after VAD implantation. Patients with SRI medication were at increased risk of bleeding. The indication and use of SRI, therefore, should be considered carefully.

The antiplatelet effect of mirtazapine is mediated by co-blocking 5-HT2A and α2-adrenergic receptors on platelets: An in vitro human plasma-based study

Mirtazapine (MTZ) is a noradrenergic and specific serotonergic antidepressant that has been associated with an increased risk of bleeding. However, there is insufficient evidence confirming this association. We hypothesised that 5-HT2A and α2 receptor-mediated inhibitory effects of MTZ on platelets suppress platelet aggregation and increase the risk of bleeding. In this study, we examined the antiplatelet effect of MTZ on human platelets to test our hypothesis. Blood samples for platelet aggregation tests were obtained from 14 healthy volunteers. The antiplatelet effect of MTZ was evaluated using light transmission aggregometry. MTZ significantly suppressed platelet aggregation mediated both by the synergistic interaction of serotonin (5-HT) and adrenaline and the synergistic interaction of ADP and 5-HT or adrenaline. In conclusion, MTZ exerts its antiplatelet effects by co-blocking the 5-HT2A and α2-adrenergic receptors on platelets and also suppresses platelet aggregation induced by ADP and 5-HT or adrenaline. Therefore, when MTZ is used, especially for patients with a high risk of bleeding, the significance of its use must be considered carefully. In addition, the platelet aggregation pattern by adrenaline + 5-HT, ADP + adrenaline, and ADP + 5-HT was similar between humans and mice; however, this study did not directly compare the effects of MTZ on human and murine platelets. Therefore, under the conditions for inducing platelet aggregation using adrenaline + 5-HT, ADP + adrenaline, and ADP + 5-HT, mouse platelets can be used in the evaluation of the efficacy of antiplatelet drugs in humans.

Psychotropic Medications in Metabolic and Bariatric Surgery: Research Updates and Clinical Considerations

PURPOSE OF REVIEW

We review evidence for assessing and monitoring psychotropic medications in metabolic and bariatric surgery (MBS) patients. We describe weight gain side effects, potential perioperative risks, pharmacokinetic changes that occur after MBS, and conclude with clinical recommendations.

RECENT FINDINGS

Research on psychiatric medication use and post-MBS weight outcomes is lacking and inconsistent; however, there is consistent evidence that, though variable, psychiatric medication use is associated with weight gain. Several meta-analyses and reviews provide guidance on lowering risk when appropriate. Perioperative lithium toxicity and SSRI discontinuation syndrome also warrant consideration, as do potential post-operative pharmacokinetic changes. In the absence of data for each psychiatric drug classification, close symptom monitoring and, where appropriate, serum concentration monitoring are recommended. MBS patients are a psychiatrically vulnerable population, and many are on psychiatric medications. Given potential weight/metabolic side effects, perioperative complications, and post-operative pharmacokinetic changes that occur with psychotropic medication use, providers should stay well informed on psychiatric medication management considerations.

Association of bleeding with serotonergic antidepressants in patients receiving left ventricular assist device support

STUDY OBJECTIVE

This study sought to determine whether SA use is associated with bleeding in patients receiving CF-LVAD support.

DESIGN

A retrospective cohort analysis was conducted of all adult patients who received CF-LVAD implantation at our institution.

SETTING

Barnes-Jewish Hospital between July 1, 2009, and October 1, 2018.

PATIENTS

Patients at least 18 years of age who received a HVAD™ (HeartWare Corp.), HeartMate II™ (St. Jude Medical), or HeartMate 3™ (St. Jude Medical) CF-LVAD and survived for at least 30 days postoperatively were included.

INTERVENTION

Patients who received SAs (n = 203) were compared to those who did not (n = 391) from 30 days to 18 months following implantation. The primary outcome was the incidence of first bleeding events including gastrointestinal bleed (GIB), epistaxis, or intracerebral hemorrhage (ICH).

MEASUREMENTS AND MAIN RESULTS

During follow-up, 219 patients had bleeding events: 93 of 203 (45.8%) in the SA group versus 126 of 391 (32.2%) in the control group (p = 0.001). After adjustment for age, angiotensin-converting enzyme (ACE) inhibitor and angiotensin receptor blocker (ARB) use, history of bleeding events, history of smoking, and CF-LVAD type, SA use remained associated with bleeding (adjusted odds ratio: 1.75, 95% confidence interval: 1.22-2.51, p = 0.002). HeartMate 3™ patients experienced less bleeding than HeartMate II™ patients (adjusted odds ratio 0.46, 95% confidence interval: 0.23-0.90, p = 0.024).

CONCLUSIONS

In this single-center, retrospective cohort of patients supported with CF-LVADs, SA use was associated with the incidence of first bleeding events, primarily driven by GIB. Further studies are needed to assess any differential risk of bleeding among SA agents and to assess the utility of altering antithrombotic strategies.

The Psychopharmacology Algorithm Project at the Harvard South Shore Program: An Update on Unipolar Nonpsychotic Depression

BACKGROUND

The Psychopharmacology Algorithm Project at the Harvard South Shore Program presents evidence-based recommendations considering efficacy, tolerability, safety, and cost. Two previous algorithms for unipolar nonpsychotic depression were published in 1993 and 1998. New studies over the last 20 years suggest that another update is needed.

METHODS

The references reviewed for the previous algorithms were reevaluated, and a new literature search was conducted to identify studies that would either support or alter the previous recommendations. Other guidelines and algorithms were consulted. We considered exceptions to the main algorithm, as for pregnant women and patients with anxious distress, mixed features, or common medical and psychiatric comorbidities.

SUMMARY

For inpatients with severe melancholic depression and acute safety concerns, electroconvulsive therapy (or ketamine if ECT refused or ineffective) may be the first-line treatment. In the absence of an urgent indication, we recommend trialing venlafaxine, mirtazapine, or a tricyclic antidepressant. These may be augmented if necessary with lithium or T3 (triiodothyronine). For inpatients with non-melancholic depression and most depressed outpatients, sertraline, escitalopram, and bupropion are reasonable first choices. If no response, the prescriber (in collaboration with the patient) has many choices for the second trial in this algorithm because there is no clear preference based on evidence, and there are many individual patient considerations to take into account. If no response to the second medication trial, the patient is considered to have a medication treatment-resistant depression. If the patient meets criteria for the atypical features specifier, a monoamine oxidase inhibitor could be considered. If not, reconsider (for the third trial) some of the same options suggested for the second trial. Some other choices can also considered at this stage. If the patient has comorbidities such as chronic pain, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, or posttraumatic stress disorder, the depression could be secondary; evidence-based treatments for those disorders would then be recommended.

Antidepressants: bleeding or thrombosis?

The contribution of depression to the pathogenesis of cardiovascular disease includes autonomic disturbances, endothelial dysfunction, inflammation, smoking, sedentary lifestyle, carbohydrate craving, and impaired fibrinolysis. There is evidence that serotonergic antidepressants (selective serotonin reuptake inhibitors and serotonin and noradrenaline reuptake inhibitors) restore the fibrinolytic profile. Contrary to common belief, such antidepressants do not affect platelet aggregation induced by adenosine diphosphate or adrenaline but reduce platelet adhesion to collagen. Since platelet collagen receptor glycoprotein VI binds to fibrin, it is possible that fibrinolytic properties of serotonergic antidepressants could impair platelet adhesion to collagen. The profibrinolytic and antiplatelet properties of serotonergic antidepressants help explain the increased risk of gastrointestinal, intracranial, and surgical bleeding in patients using these medications. Studies evaluating the impact of antidepressants on thrombotic and cardiovascular risk have yielded contradictory results. Corroborating the hypothesis that serotonergic antidepressants have profibrinolytic and antiplatelet properties, some authors showed that these medications prevent both cardiovascular and thromboembolic events. Others showed an increased risk of ischemic stroke, cardiac events and thromboembolic disease. Silent brain infarction may present in some elders with depressive symptoms, so it is presumed that antidepressants are prescribed for subclinical stroke patients. Another explanation for the increased risk of cardiovascular and thromboembolic events reported by some authors in individuals taking antidepressants includes antidepressant side effects such as sedation and weight gain and depression comorbidities such as anxiety, obesity and hyperhomocysteinemia. In conclusion, we suggest that serotonergic antidepressants be considered weak anticoagulants. We also suggest that depressed patients with comorbidities increasing the risk of cardiovascular and thromboembolic disease be recommended to follow a balanced diet and engage in physical activity, such as daily walking.

Association of Antidepressant Use With Adverse Health Outcomes: A Systematic Umbrella Review

IMPORTANCE

Antidepressant use is increasing worldwide. Yet, contrasting evidence on the safety of antidepressants is available from meta-analyses, and the credibility of these findings has not been quantified.

OBJECTIVE

To grade the evidence from published meta-analyses of observational studies that assessed the association between antidepressant use or exposure and adverse health outcomes.

DATA SOURCES

PubMed, Scopus, and PsycINFO were searched from database inception to April 5, 2019.

EVIDENCE REVIEW

Only meta-analyses of observational studies with a cohort or case-control study design were eligible. Two independent reviewers recorded the data and assessed the methodological quality of the included meta-analyses. Evidence of association was ranked according to established criteria as follows: convincing, highly suggestive, suggestive, weak, or not significant.

RESULTS

Forty-five meta-analyses (17.9%) from 4471 studies identified and 252 full-text articles scrutinized were selected that described 120 associations, including data from 1012 individual effect size estimates. Seventy-four (61.7%) of the 120 associations were nominally statistically significant at P ≤ .05 using random-effects models. Fifty-two associations (43.4%) had large heterogeneity (I2 > 50%), whereas small-study effects were found for 17 associations (14.2%) and excess significance bias was found for 9 associations (7.5%). Convincing evidence emerged from both main and sensitivity analyses for the association between antidepressant use and risk of suicide attempt or completion among children and adolescents, autism spectrum disorders with antidepressant exposure before and during pregnancy, preterm birth, and low Apgar scores. None of these associations remained supported by convincing evidence after sensitivity analysis, which adjusted for confounding by indication.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that most putative adverse health outcomes associated with antidepressant use may not be supported by convincing evidence, and confounding by indication may alter the few associations with convincing evidence. Antidepressant use appears to be safe for the treatment of psychiatric disorders, but more studies matching for underlying disease are needed to clarify the degree of confounding by indication and other biases. No absolute contraindication to antidepressants emerged from this umbrella review.

Concomitant Anticoagulant and Antidepressant Therapy in Atrial Fibrillation Patients and Risk of Stroke and Bleeding

We aimed to quantify the effects of antidepressant (AD) use in oral anticoagulant (OAC)-treated patients with atrial fibrillation (AF). Using the Stockholm Healthcare database, we analyzed AF patients initiated with an OAC. Outcomes were severe bleeds and strokes and were analyzed using Cox models. We included 17,210 patients claiming warfarin and 13,385 claiming a non-vitamin K OAC. The number of patients that claimed an AD during follow-up was 4,303. Concomitant OAC and AD use was associated with increased rates of severe bleeds (4.7 vs. 2.7 per 100 person-years) compared with OAC treatment alone (adjusted hazard ratio (aHR) 1.42, confidence interval (CI): 1.12-1.80), but not significantly associated with increased stroke rates (3.5 vs. 2.1 per 100 person-years, aHR 1.23, CI: 0.93-1.62). No significant differences in risks were observed between different OAC classes or different AD classes. In conclusion, concomitant use of an OAC and an AD is associated with an increased bleeding risk.

Diving and attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a psychiatric condition that affects attention, concentration, impulse control and awareness. Not only these symptoms, but also the medications used to treat ADHD (psychostimulants) pose a risk to both the diver and his or her buddy. This article presents guidelines for recreational diving in combination with ADHD and psychostimulants. These guidelines are based solely on 'expert' opinion and were adopted at a meeting of the Dutch Association for Diving Medicine in 2017.

Clinical Management of Bleeding Risk With Antidepressants

Objective: This nonsystematic review describes risk of bleeding in treatment with serotonin reuptake inhibitors (SRIs) and provide recommendations for the management of patients at risk of bleeding. Data Sources: Articles were identified by English-language MEDLINE search published prior to June 2018 using the terms SRI, serotonin and noradrenaline reuptake inhibitors, OR antidepressive agents, AND hemorrhage OR stroke. Study Selection and Data Extraction: Meta-analyses were utilized to identify information regarding risk of bleeding with antidepressants. Individual studies were included if they had information regarding bleeding risk with specific SRIs, timing of risk, or risk with medications of interest. Data Synthesis: SRIs increase risk of bleeding by 1.16- to 2.36-fold. The risk is synergistic between SRIs and nonsteroidal anti-inflammatory drugs (NSAIDs; odds ratio [OR] range between studies 3.17-10.9). Acid-reducing medications may mitigate risk of gastrointestinal bleeds in chronic NSAIDs and SRI users (OR range between studies 0.98-1.1). Antidepressants with low or no affinity for the serotonin transporter, such as bupropion or mirtazapine, may be appropriate alternatives for patients at risk of bleeding. Relevance to Patient Care and Clinical Practice: This review includes data regarding bleeding risk for specific antidepressants, concomitant medications, and risk related to duration of SRI use. Considerations and evidence-based recommendations are provided for management of SRI users at high bleeding risk. Conclusions: Clinicians must be aware of the risk of bleeding with SRI use, especially for patients taking NSAIDs. Patient education is prudent for those prescribed NSAIDs and SRIs concurrently.

Mirtazapine for fibromyalgia in adults

BACKGROUND

Fibromyalgia is a clinically defined chronic condition of unknown etiology characterised by chronic widespread pain, sleep disturbance, cognitive dysfunction, and fatigue. Many patients report high disability levels and poor quality of life. Drug therapy aims to reduce key symptoms, especially pain, and improve quality of life. The tetracyclic antidepressant, mirtazapine, may help by increasing serotonin and noradrenaline in the central nervous system (CNS).

OBJECTIVES

To assess the efficacy, tolerability and safety of the tetracyclic antidepressant, mirtazapine, compared with placebo or other active drug(s) in the treatment of fibromyalgia in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, SCOPUS, the US National Institutes of Health, and the World Health Organization (WHO) International Clinical Trials Registry Platform for published and ongoing trials, and examined reference lists of reviewed articles, to 9 July 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of any formulation of mirtazapine against placebo, or any other active treatment of fibromyalgia, in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted study characteristics, outcomes of efficacy, tolerability and safety, examined issues of study quality, and assessed risk of bias, resolving discrepancies by discussion. Primary outcomes were participant-reported pain relief (at least 50% or 30% pain reduction), Patient Global Impression of Change (PGIC; much or very much improved), safety (serious adverse events), and tolerability (adverse event withdrawal). Other outcomes were health-related quality of life (HRQoL) improved by 20% or more, fatigue, sleep problems, mean pain intensity, negative mood and particular adverse events. We used a random-effects model to calculate risk difference (RD), standardised mean difference (SMD), and numbers needed to treat. We assessed the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

Three studies with 606 participants compared mirtazapine with placebo (but not other drugs) over seven to 13 weeks. Two studies were at unclear or high risk of bias in six or seven of eight domains. We judged the evidence for all outcomes to be low- or very low-quality because of poor study quality, indirectness, imprecision, risk of publication bias, and sometimes low numbers of events.There was no difference between mirtazapine and placebo for any primary outcome: participant-reported pain relief of 50% or greater (22% versus 16%; RD 0.05, 95% confidence interval (CI) -0.01 to 0.12; three studies with 591 participants; low-quality evidence); no data available for PGIC; only a single serious adverse event for evaluation of safety (RD -0.00, 95% CI -0.01 to 0.02; three studies with 606 participants; very low-quality evidence); and tolerability as frequency of dropouts due to adverse events (3% versus 2%; RD 0.00, 95% CI -0.02 to 0.03; three studies with 606 participants; low-quality evidence).Mirtazapine showed a clinically-relevant benefit compared to placebo for some secondary outcomes: participant-reported pain relief of 30% or greater (47% versus 34%; RD 0.13, 95% CI 0.05 to 0.21; number needed to treat for an additional beneficial outcome (NNTB) 8, 95% CI 5 to 20; three studies with 591 participants; low-quality evidence); participant-reported mean pain intensity (SMD -0.29, 95% CI -0.46 to -0.13; three studies with 591 participants; low-quality evidence); and participant-reported sleep problems (SMD -0.23, 95% CI -0.39 to -0.06; three studies with 573 participants; low-quality evidence). There was no benefit for improvement of participant-reported improvement of HRQoL of 20% or greater (58% versus 50%; RD 0.08, 95% CI -0.01 to 0.16; three studies with 586 participants; low-quality evidence); participant-reported fatigue (SMD -0.02, 95% CI -0.19 to 0.16; two studies with 533 participants; low-quality evidence); participant-reported negative mood (SMD -0.67, 95% CI -1.44 to 0.10; three studies with 588 participants; low-quality evidence); or withdrawals due to lack of efficacy (1.5% versus 0.1%; RD 0.01, 95% CI -0.01 to 0.02; three studies with 605 participants; very low-quality evidence).There was no difference between mirtazapine and placebo for participants reporting any adverse event (76% versus 59%; RD 0.12, 95 CI -0.01 to 0.26; three studies with 606 participants; low-quality evidence). There was a clinically-relevant harm with mirtazapine compared to placebo: in the number of participants with somnolence (42% versus 14%; RD 0.24, 95% CI 0.18 to 0.30; number needed to treat for an additional harmful outcome (NNTH) 5, 95% CI 3 to 6; three studies with 606 participants; low-quality evidence); weight gain (19% versus 1%; RD 0.17, 95% CI 0.11 to 0.23; NNTH 6, 95% CI 5 to 10; three studies with 606 participants; low-quality evidence); and elevated alanine aminotransferase (13% versus 2%; RD 0.13, 95% CI 0.04 to 0.22; NNTH 8, 95% CI 5 to 25; two studies with 566 participants; low-quality evidence).

AUTHORS' CONCLUSIONS

Studies demonstrated no benefit of mirtazapine over placebo for pain relief of 50% or greater, PGIC, improvement of HRQoL of 20% or greater, or reduction of fatigue or negative mood. Clinically-relevant benefits were shown for pain relief of 30% or greater, reduction of mean pain intensity, and sleep problems. Somnolence, weight gain, and elevated alanine aminotransferase were more frequent with mirtazapine than placebo. The quality of evidence was low or very low, with two of three studies of questionable quality and issues over indirectness and risk of publication bias. On balance, any potential benefits of mirtazapine in fibromyalgia were outweighed by its potential harms, though, a small minority of people with fibromyalgia might experience substantial symptom relief without clinically-relevant adverse events.