Low-dose amitriptyline for treatment of persistent arm pain due to repetitive use

Antidepressants for pain management in adults with chronic pain: a network meta-analysis

BACKGROUND

Chronic pain is common in adults, and often has a detrimental impact upon physical ability, well-being, and quality of life. Previous reviews have shown that certain antidepressants may be effective in reducing pain with some benefit in improving patients' global impression of change for certain chronic pain conditions. However, there has not been a network meta-analysis (NMA) examining all antidepressants across all chronic pain conditions.

OBJECTIVES

To assess the comparative efficacy and safety of antidepressants for adults with chronic pain (except headache).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, AMED and PsycINFO databases, and clinical trials registries, for randomised controlled trials (RCTs) of antidepressants for chronic pain conditions in January 2022.

SELECTION CRITERIA

We included RCTs that examined antidepressants for chronic pain against any comparator. If the comparator was placebo, another medication, another antidepressant, or the same antidepressant at different doses, then we required the study to be double-blind. We included RCTs with active comparators that were unable to be double-blinded (e.g. psychotherapy) but rated them as high risk of bias. We excluded RCTs where the follow-up was less than two weeks and those with fewer than 10 participants in each arm.  DATA COLLECTION AND ANALYSIS: Two review authors separately screened, data extracted, and judged risk of bias. We synthesised the data using Bayesian NMA and pairwise meta-analyses for each outcome and ranked the antidepressants in terms of their effectiveness using the surface under the cumulative ranking curve (SUCRA). We primarily used Confidence in Meta-Analysis (CINeMA) and Risk of Bias due to Missing Evidence in Network meta-analysis (ROB-MEN) to assess the certainty of the evidence. Where it was not possible to use CINeMA and ROB-MEN due to the complexity of the networks, we used GRADE to assess the certainty of the evidence. Our primary outcomes were substantial (50%) pain relief, pain intensity, mood, and adverse events. Our secondary outcomes were moderate pain relief (30%), physical function, sleep, quality of life, Patient Global Impression of Change (PGIC), serious adverse events, and withdrawal.

MAIN RESULTS

This review and NMA included 176 studies with a total of 28,664 participants. The majority of studies were placebo-controlled (83), and parallel-armed (141). The most common pain conditions examined were fibromyalgia (59 studies); neuropathic pain (49 studies) and musculoskeletal pain (40 studies). The average length of RCTs was 10 weeks. Seven studies provided no useable data and were omitted from the NMA. The majority of studies measured short-term outcomes only and excluded people with low mood and other mental health conditions. Across efficacy outcomes, duloxetine was consistently the highest-ranked antidepressant with moderate- to high-certainty evidence. In duloxetine studies, standard dose was equally efficacious as high dose for the majority of outcomes. Milnacipran was often ranked as the next most efficacious antidepressant, although the certainty of evidence was lower than that of duloxetine. There was insufficient evidence to draw robust conclusions for the efficacy and safety of any other antidepressant for chronic pain.  Primary efficacy outcomes Duloxetine standard dose (60 mg) showed a small to moderate effect for substantial pain relief (odds ratio (OR) 1.91, 95% confidence interval (CI) 1.69 to 2.17; 16 studies, 4490 participants; moderate-certainty evidence) and continuous pain intensity (standardised mean difference (SMD) -0.31, 95% CI -0.39 to -0.24; 18 studies, 4959 participants; moderate-certainty evidence). For pain intensity, milnacipran standard dose (100 mg) also showed a small effect (SMD -0.22, 95% CI -0.39 to 0.06; 4 studies, 1866 participants; moderate-certainty evidence). Mirtazapine (30 mg) had a moderate effect on mood (SMD -0.5, 95% CI -0.78 to -0.22; 1 study, 406 participants; low-certainty evidence), while duloxetine showed a small effect (SMD -0.16, 95% CI -0.22 to -0.1; 26 studies, 7952 participants; moderate-certainty evidence); however it is important to note that most studies excluded participants with mental health conditions, and so average anxiety and depression scores tended to be in the 'normal' or 'subclinical' ranges at baseline already. Secondary efficacy outcomes Across all secondary efficacy outcomes (moderate pain relief, physical function, sleep, quality of life, and PGIC), duloxetine and milnacipran were the highest-ranked antidepressants with moderate-certainty evidence, although effects were small. For both duloxetine and milnacipran, standard doses were as efficacious as high doses. Safety There was very low-certainty evidence for all safety outcomes (adverse events, serious adverse events, and withdrawal) across all antidepressants. We cannot draw any reliable conclusions from the NMAs for these outcomes.

AUTHORS' CONCLUSIONS

Our review and NMAs show that despite studies investigating 25 different antidepressants, the only antidepressant we are certain about for the treatment of chronic pain is duloxetine. Duloxetine was moderately efficacious across all outcomes at standard dose. There is also promising evidence for milnacipran, although further high-quality research is needed to be confident in these conclusions. Evidence for all other antidepressants was low certainty. As RCTs excluded people with low mood, we were unable to establish the effects of antidepressants for people with chronic pain and depression. There is currently no reliable evidence for the long-term efficacy of any antidepressant, and no reliable evidence for the safety of antidepressants for chronic pain at any time point.

Psychiatric disorders and pain: The recurrence of a comorbidity

Painful conditions are probably among the most frequent reasons for seeking medical advice and assistance. Although pain is a common complaint among psychiatric patients, clinicians generally separate its presence from the background mental disorder and downplay its importance, trying primarily to control the psychiatric symptomatology. As a sensory modality, the presence of pain and its importance account for an impressive body of scholarly research. Cartesian methodology considered sensations of all modalities in a mechanistic form, which actually sounds obsolete. However, authors have continuously been faced with the same dilemmas plaguing scholars for centuries. We assume that a large portion of the sensory inputs might be generators of distorted perceptions, which subsequently lead to psychopathology. Auditory and visual hallucinations are incontestable examples. Somaesthetic hallucinations also exist, but pain hardly deserves such a denomination. Nevertheless, chronic pain and psychiatric comorbidity is a reality that needs explanation. Painkillers are not effective in treating psychiatric disorders, and antipsychotics do very little, perhaps nothing, to relieve pain. The pharmacological approach opens one door on the horizon and closes many others, while clinicians continue to face a high prevalence of comorbid pain and mental health issues. However, attempts to correlate altered body schemata (as distorted as it may be, for example, in phantom limb pain) with somatic delusions can simplify all these dilemmas, and the basket of psychophysiology, in fact, might be bigger than presumed.

Adverse Effects of Antidepressants for Chronic Pain: A Systematic Review and Meta-analysis

Background

Antidepressants are widely used in the treatment of chronic pain. Applied doses are lower than those needed to unfold an antidepressive effect. While efficacy of antidepressants for chronic pain has been reported in large randomized-controlled trials (RCT), there is inconsistent data on adverse effects and tolerability. We aimed at synthesizing data from RCT to explore adverse effect profiles and tolerability of antidepressants for treatment of chronic pain.

Methods

Systematic literature research and meta-analyses were performed regarding side effects and safety of different antidepressants in the treatment of chronic pain according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The National Center for Biotechnology Information library and MEDLINE were searched. Randomized placebo-controlled trials were included in quantitative data synthesis.

Results

Out of 1,975 screened articles, 33 papers published between 1995 and 2015 were included in our review and 23 studies were included in the meta-analyses. A higher risk for adverse effects compared to placebo was observed in all antidepressants included in our analyses, except nortriptyline. The most prevalent adverse effects were dry mouth, dizziness, nausea, headache, and constipation. Amitriptyline, mirtazapine, desipramine, venlafaxine, fluoxetine, and nortriptyline showed the highest placebo effect-adjusted risk of adverse effects. Risk for withdrawal due to adverse effects was highest in desipramine (risk ratio: 4.09, 95%-confidence interval [1.31; 12.82]) followed by milnacipran, venlafaxine, and duloxetine. The most common adverse effects under treatment with antidepressants were dry mouth, dizziness, nausea, headache, and constipation followed by palpitations, sweating, and drowsiness. However, overall tolerability was high. Each antidepressant showed distinct risk profiles of adverse effects.

Conclusion

Our synthesized data analysis confirmed overall tolerability of low-dose antidepressants for the treatment of chronic pain and revealed drug specific risk profiles. This encompassing characterization of adverse effect profiles might be useful in defining multimodal treatment regimens for chronic pain which also consider patients’ comorbidities and co-medication.

Amitriptyline for musculoskeletal complaints: a systematic review

BACKGROUND

The role of amitriptyline in musculoskeletal pain is not as clearly defined as in classical neuropathic pain conditions.

OBJECTIVE

To assess the efficacy and effectiveness of amitriptyline in the treatment of pain in musculoskeletal complaints.

METHODS

An extensive search (including Medline, Embase and Web of Science) was made up to April 2016 for randomised controlled trials on amitriptyline in musculoskeletal complaints compared to placebo, usual care, or other analgesic use. Included studies were assessed for risk of bias. Outcomes of interest were pain reduction and function improvement.

RESULTS

Of the 2066 articles identified, seven were finally included. These studies were performed in patients with low back pain (4), rheumatoid arthritis (2), and patients with arm pain from repetitive use (1). No meta-analysis was performed due to clinical heterogeneity of the studies. Two studies with low risk of bias found positive results. One study found that 50 mg/day of amitriptyline [Visual Analogue Scale (VAS) -3.9 points] resulted in a significantly greater reduction in pain than treatment with pregabalin 600 mg/day (VAS -2.9 points) and improved function (improvement on the Oswestry Disability Index >20%: 65% versus 49.5%). Amitriptyline improved function in arm pain compared to placebo (Upper Extremity Function Scale: -3.9 versus 0.8). A similar amount of side-effects occurred in the amitriptyline and the comparison groups.

CONCLUSION

Few studies have evaluated the use of amitriptyline in musculoskeletal complaints. Although amitriptyline may be effective in musculoskeletal complaints, more studies are required to establish for whom amitriptyline works better than other analgesics.

Reporting of sample size calculations in analgesic clinical trials: ACTTION systematic review

Sample size calculations determine the number of participants required to have sufficiently high power to detect a given treatment effect. In this review, we examined the reporting quality of sample size calculations in 172 publications of double-blind randomized controlled trials of noninvasive pharmacologic or interventional (ie, invasive) pain treatments published in European Journal of Pain, Journal of Pain, and Pain from January 2006 through June 2013. Sixty-five percent of publications reported a sample size calculation but only 38% provided all elements required to replicate the calculated sample size. In publications reporting at least 1 element, 54% provided a justification for the treatment effect used to calculate sample size, and 24% of studies with continuous outcome variables justified the variability estimate. Publications of clinical pain condition trials reported a sample size calculation more frequently than experimental pain model trials (77% vs 33%, P < .001) but did not differ in the frequency of reporting all required elements. No significant differences in reporting of any or all elements were detected between publications of trials with industry and nonindustry sponsorship. Twenty-eight percent included a discrepancy between the reported number of planned and randomized participants. This study suggests that sample size calculation reporting in analgesic trial publications is usually incomplete. Investigators should provide detailed accounts of sample size calculations in publications of clinical trials of pain treatments, which is necessary for reporting transparency and communication of pre-trial design decisions.

PERSPECTIVE

In this systematic review of analgesic clinical trials, sample size calculations and the required elements (eg, treatment effect to be detected; power level) were incompletely reported. A lack of transparency regarding sample size calculations may raise questions about the appropriateness of the calculated sample size.

Conservative interventions for treating work-related complaints of the arm, neck or shoulder in adults

BACKGROUND

Work-related upper limb disorder (WRULD), repetitive strain injury (RSI), occupational overuse syndrome (OOS) and work-related complaints of the arm, neck or shoulder (CANS) are the most frequently used umbrella terms for disorders that develop as a result of repetitive movements, awkward postures and impact of external forces such as those associated with operating vibrating tools. Work-related CANS, which is the term we use in this review, severely hampers the working population.

OBJECTIVES

To assess the effects of conservative interventions for work-related complaints of the arm, neck or shoulder (CANS) in adults on pain, function and work-related outcomes.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, 31 May 2013), MEDLINE (1950 to 31 May 2013), EMBASE (1988 to 31 May 2013), CINAHL (1982 to 31 May 2013), AMED (1985 to 31 May 2013), PsycINFO (1806 to 31 May 2013), the Physiotherapy Evidence Database (PEDro; inception to 31 May 2013) and the Occupational Therapy Systematic Evaluation of Evidence Database (OTseeker; inception to 31 May 2013). We did not apply any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-randomised controlled trials evaluating conservative interventions for work-related complaints of the arm, neck or shoulder in adults. We excluded trials undertaken to test injections and surgery. We included studies that evaluated effects on pain, functional status or work ability.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data and assessed risk of bias of the included studies. When studies were sufficiently similar, we performed statistical pooling of reported results.

MAIN RESULTS

We included 44 studies (62 publications) with 6,580 participants that evaluated 25 different interventions. We categorised these interventions according to their working mechanisms into exercises, ergonomics, behavioural and other interventions.Overall, we judged 35 studies as having a high risk of bias mainly because of an unknown randomisation procedure, lack of a concealed allocation procedure, unblinded trial participants or lack of an intention-to-treat analysis.We found very low-quality evidence showing that exercises did not improve pain in comparison with no treatment (five studies, standardised mean difference (SMD) -0.52, 95% confidence interval (CI) -1.08 to 0.03), or minor intervention controls (three studies, SMD -0.25, 95% CI -0.87 to 0.37) or when provided as additional treatment (two studies, inconsistent results) at short-term follow-up or at long-term follow-up. Results were similar for recovery, disability and sick leave. Specific exercises led to increased pain at short-term follow-up when compared with general exercises (four studies, SMD 0.45, 95% CI 0.14 to 0.75)We found very low-quality evidence indicating that ergonomic interventions did not lead to a decrease in pain when compared with no intervention at short-term follow-up (three studies, SMD -0.07, 95% CI -0.36 to 0.22) but did decrease pain at long-term follow-up (four studies, SMD -0.76, 95% CI -1.35 to -0.16). There was no effect on disability but sick leave decreased in two studies (risk ratio (RR) 0.48, 95% CI 0.32 to 0.76). None of the ergonomic interventions was more beneficial for any outcome measures when compared with another treatment or with no treatment or with placebo.Behavioural interventions had inconsistent effects on pain and disability, with some subgroups showing benefit and others showing no significant improvement when compared with no treatment, minor intervention controls or other behavioural interventions.In the eight studies that evaluated various other interventions, there was no evidence of a clear beneficial effect of any of the interventions provided.

AUTHORS' CONCLUSIONS

We found very low-quality evidence indicating that pain, recovery, disability and sick leave are similar after exercises when compared with no treatment, with minor intervention controls or with exercises provided as additional treatment to people with work-related complaints of the arm, neck or shoulder. Low-quality evidence also showed that ergonomic interventions did not decrease pain at short-term follow-up but did decrease pain at long-term follow-up. There was no evidence of an effect on other outcomes. For behavioural and other interventions, there was no evidence of a consistent effect on any of the outcomes.Studies are needed that include more participants, that are clear about the diagnosis of work-relatedness and that report findings according to current guidelines.

Clinical anesthetic effectiveness of intraoral mucoadhesive tablets of amitriptyline in healthy volunteers

PURPOSE

Topical anesthetics are widely used in dentistry. One of their indications is to diminish the pain of the injection of anesthetics. Amitriptyline is a tricyclic antidepressant that provides local anesthetic effects by blocking the sodium channels. The present study was performed in an attempt to assess the anesthetic efficacy of an intraoral mucoadhesive tablet of amitriptyline.

MATERIALS AND METHODS

The present study was performed as a randomized, double-blind, placebo-controlled, clinical trial of 25 healthy female volunteers. The mucoadhesive tablet was randomly placed for 15 minutes on the buccal mucogingival tissue adjacent to the root of the upper lateral incisor, and a placebo was placed on the other side. A 27-gauge needle was inserted to touch the alveolar periosteum of the designated site. The pain intensity associated with the stimulation was evaluated every 5 minutes after removing the mucoadhesive tablet using a visual analog pain scale and pain rating scoring methods.

RESULTS

The difference between the amitriptyline and placebo groups was statistically significant 20, 25, 30, 35, and 40 minutes after placing the mucoadhesive tablet. Its mean onset and duration of action was 25 and 20 minutes, respectively (P<.05).

CONCLUSIONS

To our knowledge, the present study represents an initial step toward achieving an efficient and safe anesthetic method. The intraoral mucoadhesive amitriptyline tablet proved to be a promising anesthetic device for manipulating pain in dental procedures. However, it should also be mentioned that to achieve high efficiency, it will be necessary to optimize the release profile.

Reliability and validity of individual and composite recall pain measures in patients with cancer

OBJECTIVES

To evaluate and compare the validity and reliability of individual and composite recall pain intensity measures.

DESIGN

Secondary analyses using data from a published 14-day open-label crossover clinical trial comparing two active treatments.

SETTING

Multiple settings.

PARTICIPANTS

Fifty-two adults with a history of chronic cancer pain.

MEASURES

Recall ratings of least, worst, and average pain during the past 2 days; composite score representing recalled characteristic pain in the past 2 days; and daily diary ratings of pain intensity from which "actual" least, worst, and average pain scores were derived.

RESULTS

Recall ratings of least and average pain, and a composite score representing recalled characteristic pain were accurate (differed no more than three points from "actual" scores on a 0-100 scale). Although the recall rating of worst pain significantly (P < 0.05) overestimated actual worst pain, the differences were minor (i.e., seven to eight points on a 0-100 scale). All of the recall measures demonstrated validity via their strong associations with the measures of actual pain intensity. The recall measures also demonstrated excellent test-retest stability, although the diary-derived measures tended to be more stable than the recall measures did. The composite measure of recalled characteristic pain demonstrated a high level of internal consistency (Cronbach's α = 0.90).

CONCLUSIONS

Individual recall ratings and a composite score representing recalled characteristic pain intensity are reliable and valid measures of actual pain in patients with cancer. The findings support their use as outcome measures in clinical trials.

Milnacipran dose-effect study in patients with burning mouth syndrome

OBJECTIVE

The object of this study was to evaluate the dose-dependent efficacy and tolerability of milnacipran in patients with burning mouth syndrome (BMS) with inadequate response at low doses.

METHODS

A 12-week open-label dose-escalation study was conducted in 56 female patients (aged 20-83 years, with a mean age of 60.8 years). The initial dosage of milnacipran was 30 mg/d, and the dosage was raised up to 60 mg and 90 mg/d every 4 weeks until an improvement of at least 50% reduction of visual analog scale was achieved.

RESULTS

The mean ± SD effective daily dose of milnacipran was 63.9 ±16.7 mg. The cumulative improvement rate for the daily dose of 30 mg was 28.6%, and this rate rose (50.8%-67.9%) as the daily dose was increased (from 60 to 90 mg, respectively). The cumulative proportion of responders was significantly greater, with maximal daily doses of 60 and 90 mg, compared with that of 30 mg (P < 0.05, χ test). Most adverse events appeared at the low dose, and there was little evidence for dose-dependence of adverse effects. No serious safety issues were observed.

CONCLUSION

From the result of this study, dose escalation of milnacipran for patients with burning mouth syndrome with inadequate response at low doses may be helpful if the 30-mg daily dose has been tolerated well.