Low-dose amitriptyline as an adjunct to opioids for postoperative orthopedic pain: a placebo-controlled trial

Tricyclic Antidepressants in Nociceptive and Neuropathic Pain: A Review of Their Analgesic Properties in Combination With Opioids

Objectives: To determine the efficacy and safety of commonly prescribed tricyclic antidepressants (TCAs) as analgesics for nociceptive and neuropathic pain in combination with opioids. Data Sources: A comprehensive literature review was conducted with the assistance of a medical reference librarian on PubMed, MEDLINE, Scopus, and Web of Science using the following search terminology: "Amitriptyline" OR "Doxepin" OR "Desipramine" OR "Imipramine" OR "Nortriptyline" OR "Clomipramine" OR "Trimipramine" AND "Analgesia." Reports of adult patients who received any TCA as an adjunctive analgesic to opioids were included. Study Selection and Data Extraction: A total of 293 results were obtained from the initial database inquiries, following which exclusion criteria were applied and 6 articles were included in this review. Three of the reports detailed the use of TCAs in the perioperative setting, whereas the remaining 3 evaluated their effect on different etiologies of neuropathic pain. Data Synthesis: Tricyclic antidepressants were found to have modest, yet not insignificant, independent analgesic properties, although the ability to provide pain relief was relegated to a select few agents. Desipramine has the most data available for use in nociceptive, postoperative pain through its ability to potentiate and prolong the analgesic effects of opioids and was not associated with adverse drug effects. Conclusions: The efficacy of TCAs for neuropathic pain was not corroborated by this review, and the anticholinergic adverse effects associated with this drug class were found to be significant. Further research is needed to quantify the efficacy of TCAs in the management of nociceptive pain.

Consensus Guidelines on Interventional Therapies for Knee Pain (STEP Guidelines) from the American Society of Pain and Neuroscience

Knee pain is second only to the back as the most commonly reported area of pain in the human body. With an overall prevalence of 46.2%, its impact on disability, lost productivity, and cost on healthcare cannot be overlooked. Due to the pervasiveness of knee pain in the general population, there are no shortages of treatment options available for addressing the symptoms. Ranging from physical therapy and pharmacologic agents to interventional pain procedures to surgical options, practitioners have a wide array of options to choose from - unfortunately, there is no consensus on which treatments are "better" and when they should be offered in comparison to others. While it is generally accepted that less invasive treatments should be offered before more invasive ones, there is a lack of agreement on the order in which the less invasive are to be presented. In an effort to standardize the treatment of this extremely prevalent pathology, the authors present an all-encompassing set of guidelines on the treatment of knee pain based on an extensive literature search and data grading for each of the available alternative that will allow practitioners the ability to compare and contrast each option.

The expanding role of chronic pain interventions in multimodal perioperative pain management: a narrative review

Surgery is a risk factor for chronic pain and long-term opioid use. As perioperative pain management continues to evolve, treatment modalities traditionally used for chronic pain therapy may provide additional benefit to patients undergoing surgery. Interventions such as radiofrequency ablation, cryoneurolysis, and neuromodulation may potentially be used in conjunction with acute pain procedures such as nerve blocks and multimodal analgesia. Pharmacological agents associated with chronic pain medicine, including gabapentinoids, ketamine, and selective serotonin reuptake inhibitors, may be useful adjuncts in perioperative pain management when indicated. There may also be a role for acupuncture, music therapy, and other integrative medicine therapies. A transitional pain service can help coordinate outpatient care with inpatient perioperative pain management and promote a more personalized and comprehensive approach that can improve postoperative outcomes.

A Behavioral Study of Promethazine Interaction with Analgesic Effect of Diclofenac: Pain Combination Therapy

OBJECTIVES

Pain is considered as a cause of sickness and the most prevalent symptom which makes people visit a physician. Nowadays, combination therapy is becoming useful to relieve chronic and postsurgical pain. The aim of this study was to study the promethazine (as an antihistamine) interactions with antinociceptive effect of diclofenac (as a non-steroidal anti-inflammatory drugs).

METHODS

In initial part of the study, we investigate the analgesic effect of diclofenac. Using writhing test, we demonstrate that diclofenac significantly reduces writhe response induced by acetic acid in a dose-dependent manner. In this study, we evaluate the combination effect of promethazine on diclofenac analgesic effect.

RESULTS

We observed that diclofenac inhibited pain in the dose dependent manner which means that by increasing dose of diclofenac a significant decrease in pain was observed. This experimental setup allowed calculation of the dose that caused 50% antinociception (ED50) for diclofenac. The ED50 for diclofenac in this study was determined to be 9.1 mg/kg according our previous study. Additionally, promethazine was showed a dose-dependent inhibition of writhes. The combination of different doses of promethazine (2, 4, 6 mg / kg) with diclofenac ED50 (9.1 mg / kg) was injected to mice. Promethazine 4 and 6 mg / kg in combination with diclofenac had significantly led to increase analgesic effect of diclofenac.

CONCLUSION

In conclusion, these results add important information to the existing knowledge on combination of diclofenac and antihistamine in pain therapies to be used in clinical practice and maybe helpful in designing the future guidelines.

Opioid Use in the Postoperative Arena: Global Reduction in Opioids After Surgery Through Enhanced Recovery and Gynecologic Surgery

Enhanced recovery programs aim to reduce surgical stress to improve the patient perioperative experience. Through a combination of multimodal analgesia and maintaining a physiological state, postoperative recovery is improved. Many analgesic adjuncts are available that improve postoperative pain control and limit opioid analgesia requirements. Adjuncts are often used in combination, but different interventions may be incorporated for patient-specific and procedure-specific needs. Postoperative pain control can be optimized by continuing nonopioid adjuncts, and prescribing opioid analgesia to address breakthrough pain. Prescribing practices should balance optimizing pain relief, minimizing the risk of chronic pain, while limiting the potential for opioid misuse.

Antidepressant Drugs for Postsurgical Pain: Current Status and Future Directions

Current treatments for postsurgical pain are often inadequate and adverse effects are substantial such that residual pain and/or side effects impair recovery. The recognition of analgesic efficacy with antidepressant drugs for chronic pain suggests the potential for efficacy in acute postsurgical pain. As reviewed here, current evidence suggests that approximately half of previous trials suggest efficacy of various antidepressants for acute postoperative pain. However, most trials are older with deficiencies including: lack of designation of a primary outcome, no assessment of movement-evoked pain, small size and limited safety assessment. Only one of three trials addressing prevention of chronic postsurgical pain suggested any efficacy; however, the evidence base for this indication is limited. Thus, current evidence does not yet support routine use of any one specific antidepressant for treatment of acute, or prevention of chronic, postsurgical pain. However, limitations in available trials are such that one cannot yet rule out the possibility that one or more antidepressant drugs may provide benefit in specific populations. Therefore, future larger trials should explore optimal dosing and duration of antidepressant treatment, procedure specificity, safety evaluation, and assessment of movement-evoked pain.

Antidepressant drugs for prevention of acute and chronic postsurgical pain: early evidence and recommended future directions

BACKGROUND

This review evaluates trials of antidepressants for acute and chronic postsurgical pain.

METHODS

Trials were systematically identified using predefined inclusion and exclusion criteria. Extracted data included the following: pain at rest and with movement, adverse effects, and other outcomes.

RESULTS

Fifteen studies (985 participants) of early postoperative pain evaluated amitriptyline (three trials), bicifadine (two trials), desipramine (three trials), duloxetine (one trial), fluoxetine (one trial), fluradoline (one trial), tryptophan (four trials), and venlafaxine (one trial). Three studies (565 participants) of chronic postoperative pain prevention evaluated duloxetine (one trial), escitalopram (one trial), and venlafaxine (one trial). Heterogeneity because of differences in drug, dosing regimen, outcomes, and/or surgical procedure precluded any meta-analyses. Superiority to placebo was reported in 8 of 15 trials for early pain reduction and 1 of 3 trials for chronic pain reduction. The majority of positive trials did not report sufficient data to estimate treatment effect sizes. Many studies had inadequate size, safety evaluation/reporting, procedure specificity, and movement-evoked pain assessment.

CONCLUSIONS

There is currently insufficient evidence to support the clinical use of antidepressants-beyond controlled investigations-for treatment of acute, or prevention of chronic, postoperative pain. Multiple positive trials suggest the therapeutic potential of antidepressants, which need to be replicated. Other nontrial evidence suggests potential safety concerns of perioperative antidepressant use. Future studies are needed to better define the risk-benefit ratio of antidepressants in postoperative pain management. Higher-quality trials should optimize dosing, timing and duration of antidepressant treatment, trial size, patient selection, safety evaluation and reporting, procedure specificity, and assessment of movement-evoked pain relevant to postoperative functional recovery.

Psychiatric agents and implications for perioperative analgesia

The use of antidepressants, anxiolytics, mood stabilizers, anticonvulsants, and major tranquilizers introduces neurochemical, behavioral, cognitive, and emotional factors that increase the complexity of medical and surgical tasks. Increasingly, various classes of psychotropic medications are being prescribed in the perioperative setting for their analgesic properties in patients with or without a psychiatric diagnosis. In many cases, the precise mechanisms of action and dose-response relationships by which these agents mediate analgesia are largely unclear. An appreciation of the side effects and adverse-effect profiles of such medications and familiarity with the clinically relevant drug interactions that may occur in the perioperative setting are imperative to ensure the best possible outcome in dealing with patients on these medications. This review focuses on various classes of psychotropic agents, which are addressed individually, with particular focus on their analgesic properties. The latest published research is summarized, deficiencies in our current collective knowledge are discussed, and evidence-based recommendations are made for clinical practice.

Perioperative interventions to reduce chronic postsurgical pain

Approximately 10% of patients following a variety of surgeries develop chronic postsurgical pain. Reducing chronic postoperative pain is especially important to reconstructive surgeons because common operations such as breast and limb reconstruction have even higher risk for developing chronic postsurgical pain. Animal studies of posttraumatic nerve injury pain demonstrate that there is a critical time frame before and immediately after nerve injury in which specific interventions can reduce the incidence and intensity of chronic neuropathic pain behaviors-so called "preventative analgesia." In animal models, perineural local anesthetic, systemic intravenous local anesthetic, perineural clonidine, systemic gabapentin, systemic tricyclic antidepressants, and minocycline have each been shown to reduce pain behaviors days to weeks after treatment. The translation of this work to humans also suggests that brief perioperative interventions may protect patients from developing new chronic postsurgical pain. Recent clinical trial data show that there is an opportunity during the perioperative period to dramatically reduce the incidence and severity of chronic postsurgical pain. The surgeon, working with the anesthesiologist, has the ability to modify both early and chronic postoperative pain by implementing an evidence-based preventative analgesia plan.

Combination drug therapy for chronic pain: a call for more clinical studies

Chronic pain is a debilitating clinical condition associated with a variety of disease entities including diabetic neuropathy, postherpetic neuralgia, low back pathology, fibromyalgia, and neurological disorders. For many general practitioners and specialists, managing chronic pain has become a daunting challenge. As a modality of multidisciplinary chronic pain management, medications are often prescribed in combinations, an approach referred to as combination drug therapy (CDT). However, many medications for pain therapy, including antidepressants and opioid analgesics, have significant side effects that can compound when used in combination and impact the effectiveness of CDT. To date, clinical practice of CDT for chronic pain has been based largely on clinical experiences. In this article, we will focus on (1) the scientific basis and rationales for CDT, (2) current clinical data on CDT, and (3) the need for more clinical studies to establish a framework for the use of CDT.

PERSPECTIVE

More preclinical, clinical, and translational studies are needed to improve the efficacy of combination drug therapy that is an integral part of a comprehensive approach to the management of chronic pain.

A randomized, double-blind, 8-week crossover study of once-daily controlled-release tramadol versus immediate-release tramadol taken as needed for chronic noncancer pain

OBJECTIVE

The purpose of this study was to evaluate the efficacy of controlled-release (CR) tramadol and immediate-release (IR) tramadol in patients with moderate or greater intensity chronic noncancer pain.

METHODS

A total of 122 patients underwent washout from all opioids 2 to 7 days before randomization to 1 of 2 groups: active CR tramadol 200 mg every morning plus placebo IR tramadol 50 mg every 4 to 6 hours PRN rescue, or placebo CR tramadol 200 mg every morning plus active IR tramadol 50 mg every 4 to 6 hours PRN rescue. After 2 weeks, the doses were increased to CR tramadol 400 mg or placebo and IR tramadol 100 mg every 4 to 6 hours PRN or placebo, as rescue. After 4 weeks in the first phase, patients crossed over to the alternative treatment for another 4 weeks. Pain intensity (100-mm visual analog scale [VAS] and 5-point ordinal scales) was assessed twice daily in diaries. Pain intensity, Pain and Disability Index (PDI; 0-10 ordinal scale), Pain and Sleep Questionnaire (100-mm VAS), and analgesic effectiveness (7-point ordinal scale) were assessed at biweekly clinic visits.

RESULTS

Sixty-five patients (35 men, 30 women) completed the study. Mean (SD) age was 56.5 (12.7) years; mean (SD) weight was 82.0 (18.5) kg. Daily diary pain intensity (mean [SD]) was significantly lower in the CR tramadol group than in the IR tramadol group in the last 2 weeks of each phase (completers: VAS, 29.9 [20.5] vs 36.2 [20.4] mm, P < 0.001; ordinal scale, 1.41 [0.7] vs 1.64 [0.6], P < 0.001; intent-to-treat [ITT] population: VAS, 32.5 [22.9] vs 38.6 [21.2] mm, P < 0.003; ordinal scale, 1.50 [0.8] vs 1.72 [0.7], P < 0.002). The overall pain intensity scores from the daily diary were also significantly better with CR tramadol for both the completers and ITT. Similar results were obtained on the biweekly VAS pain intensity questionnaire. No differences were found between treatments in total PDI or overall Pain and Sleep scores in either population. For the completers, both patients and investigators rated effectiveness higher for CR tramadol than for IR tramadol (P < 0.004 and P < 0.008 for patients and investigators, respectively).

CONCLUSION

This study reports significant improvement in pain intensity with CR tramadol as compared with IR tramadol.

Antidepressants and their effect on sleep

Given the relationship between sleep and depression, there is inevitably going to be an effect of antidepressants on sleep. Current evidence suggests that this effect depends on the class of antidepressant used and the dosage. The extent of variation between the effects of antidepressants and sleep may relate to their mechanism of action. This systematic review examines randomised-controlled trials (RCTs) that have reported the effect that antidepressants appear to have on sleep. RCTs are not restricted to depressed populations, since several studies provide useful information about the effects on sleep in other groups. Nevertheless, the distinction is made between those studies because the participant's health may influence the baseline sleep profiles and the effect of the antidepressant. Insomnia is often seen with monoamine oxidase inhibitors (MAOIs), with all tricyclic antidepressants (TCAs) except amitriptyline, and all selective serotonin reuptake inhibitors (SSRIs) with venlafaxine and moclobemide as well. Sedation has been reported with all TCAs except desipramine, with mirtazapine and nefazodone, the TCA-related maprotiline, trazodone and mianserin, and with all MAOIs. REM sleep suppression has been observed with all TCAs except trimipramine, but especially clomipramine, with all MAOIs and SSRIs and with venlafaxine, trazodone and bupropion. However, the effect on sleep varies between compounds within antidepressant classes, differences relating to the amount of sedative or alerting (insomnia) effects, changes to baseline sleep parameters, differences relating to REM sleep, and the degree of sleep-related side effects.

The effect of chronic oral desipramine on capsaicin-induced allodynia and hyperalgesia: a double-blinded, placebo-controlled, crossover study

The tricyclic antidepressants are often used for the treatment of neuropathic pain. In this study, we evaluated one of these drugs on human cutaneous experimental pain. A randomized, double-blinded, placebo-controlled, crossover design methodology was conducted. Subjects participated in 2 14-day study sessions separated by a 7-day washout period. One session was with desipramine and one with placebo. At baseline, Day 7, and Day 15, quantitative sensory testing was performed to thermal and mechanical stimuli. On Day 15 only, intradermal capsaicin was injected on the volar aspect of the forearm followed by an assessment of pain and hyperalgesia. Oral desipramine had no significant effect on acute sensory thresholds, pain, secondary hyperalgesia, or flare response induced by intradermal capsaicin. Mean peak plasma levels of desipramine were within the therapeutic range for the treatment of depression. This study further supports a lack of effect of the tricyclic antidepressants on acute nociception and experimentally-induced secondary hyperalgesia.

IMPLICATIONS

Human experimental pain models have recently been developed; however, the efficacy of the tricyclic antidepressants (TCA) in these models has not been systematically studied. This investigation provides further validation of human experimental pain models and demonstrates that the chronic delivery of a TCA has no effect on human experimental pain.

Postoperative pain control in total joint arthroplasty: a prospective, randomized study of a fixed-dose, around-the-clock, oral regimen

This randomized, prospective study assessed postoperative pain control in 119 patients undergoing total joint arthroplasty. Group 1 (59 patients) received scheduled, around-the-clock, oral opioids and group 2 (60 patients) received oral opioids on an as-needed basis. Both groups had parenteral opioids available for breakthrough pain. The average scores for group 1 were lower than group 2. Differences were significant in sensory scores (AM day 1; AM and PM day 2), affective scores (PM day 2), total pain (PM day 2), visual analog scale (PM day 2), and present pain intensity index (AM day 1; PM day 2). Group 1 averaged 2.05 breakthrough pain doses and group 2 averaged 3.47 doses (P=.003), an average savings of 17.2% of the cost of pain medications during the first 2 postoperative days. The results indicate that scheduled, around-the-clock, oral opioids are an effective treatment regimen for postoperative pain control in total joint arthroplasty patients.

Modifiers of Patient-Controlled Analgesia Efficacy in Acute and Chronic Pain

Patient-controlled analgesia (PCA) is widely used as an effective tool for the treatment of acute and chronic pain. Its greatest advantage seems to be the easily achieved individualization of therapy, allowing optimum titration of analgesic dose to analgesic needs. This short review summarizes some predictors of PCA efficacy.

Evidence-based data on pain relief with antidepressants

This structured review addresses the issue of whether antidepressants have an antinociceptive (analgesic) effect for chronic pain independent of their antidepressant effect. In order to answer this question, human acute pain studies, individual placebo-controlled studies for the treatment of specific chronic pain syndromes, and metaanalytic studies were reviewed and placed into table format. Analysis of this evidence led to the following conclusions: The evidence was consistent in indicating that overall antidepressants may have an antinociceptive effect in chronic pain, and that these drugs were effective for neuropathic pain. There was also some evidence that these drugs could be effective for psychogenic or somatoform disorder-associated pain. This evidence also strongly suggested that serotonergic-noradrenergic antidepressants may have a more consistent antinociceptive effect than the serotonergic antidepressants. Finally, this evidence indicated that antidepressants could be effective for pain associated with some specific pain syndromes, such as chronic low back pain, osteoarthritis or rheumatoid arthritis, fibrositis or fibromyalgia, and ulcer healing. Possible reasons for the conflicting results of studies in this area are presented, and problems that could limit the validity of the conclusions of this review are discussed.

Single dose dihydrocodeine for acute postoperative pain

BACKGROUND

Dihydrocodeine is a synthetic opioid analgesic developed in the early 1900s. Its structure and pharmacokinetics are similar to that of codeine and it is used for the treatment of postoperative pain or as an antitussive. It is becoming increasingly important to assess the relative efficacy and harm caused by different treatments. Relative efficacy can be determined when an analgesic is compared with control under similar clinical circumstances.

OBJECTIVES

To quantitatively assess the analgesic efficacy and adverse effects of single-dose dihydrocodeine compared with placebo in randomised trials in moderate to severe postoperative pain.

SEARCH STRATEGY

Published reports were identified from a variety of electronic databases including Medline, Biological Abstracts, Embase, the Cochrane Library and the Oxford Pain Relief Database. Additional studies were identified from the reference lists of retrieved reports.

SELECTION CRITERIA

The following inclusion criteria were used: full journal publication, clinical trial, random allocation of patients to treatment groups, double blind design, adult patients, pain of moderate to severe intensity at baseline, postoperative administration of study drugs, treatment arms which included dihydrocodeine and placebo and either oral or injected (intramuscular or intravenous) administration of study drugs.

DATA COLLECTION AND ANALYSIS

Data collection and analysis: Summed pain intensity and pain relief data over 4-6 hours were extracted and converted into dichotomous information to yield the number of patients obtaining at least 50% pain relief. This was used to calculate relative benefit and number-needed-to-treat for one patient to obtain at least 50% pain relief. Single-dose adverse effect data were collected and used to calculate relative risk and number-needed-to-harm.

MAIN RESULTS

Fifty-two reports were identified as possible randomised trials which assessed dihydrocodeine in postoperative pain. Four reports met the inclusion criteria; all assessed oral dihydrocodeine. Three reports (194 patients) compared dihydrocodeine with placebo and one (120 patients) compared dihydrocodeine (30 mg or 60 mg) with ibuprofen 400 mg. For a single dose of dihydrocodeine 30 mg in moderate to severe postoperative pain the NNT for at least 50% pain relief was 8.1 (95% confidence interval 4.1 to 540) when compared with placebo over a period of 4-6 hours. Pooled data showed significantly more patients to have reported adverse effects with dihydrocodeine 30 mg than with placebo. When compared to ibuprofen 400 mg both dihydrocodeine 30 mg and 60 mg were significantly inferior.

REVIEWER'S CONCLUSIONS

A single 30 mg dose of dihydrocodeine is not sufficient to provide adequate pain relief in postoperative pain. Statistical superiority of ibuprofen 400 mg over dihydrocodeine (30 mg or 60 mg) was shown.

[Measurement and assessment of postoperative pain: a short review]

How to measure pain is a great challenge to those who desire to control adequately such a complex experience. Standardized instruments that take into consideration the patient's own account, have been developed in order to make such a task easier. In this article we carry out a revision of the instruments used mostly for measuring postoperative pain, and we point out some of the advantages and disadvantages. We emphasize the need for specific research focusing on the measurement of surgical pain, taking into consideration the multiple dimensions of a painful experience.

New developments in patient-controlled postoperative analgesia

Patient-controlled analgesia (PCA) is a newer technique for pain management. Patients are allowed to self-administer small analgesic bolus doses into a running intravenous infusion, intramuscularly, subcutaneously or even into the epidural space. Demands are usually controlled by computer-driven infusion pumps, but can also be delivered by disposable devices. Clinical experience demonstrates that individual variability in pain sensitivity and analgesic needs are of utmost importance. In contrast to earlier expectations, opioid consumption is usually higher than with restrictive conventional dosing regimes, but without an increase in serious side effects. Patients' acceptance is generally enthusiastic because of the possibility of self-control. PCA has proved its importance for pain studies, e.g. for algesimetry, to determine predictors of postoperative pain, to describe drug interactions, to evaluate the concept of pre-emptive analgesia or for pharmacokinetic designs. It is concluded that PCA results have been urgently required in order to change the mind of physicians and nursing staff with respect to individual pain management strategies. Once this goal is achieved, PCA concepts should also be used for the improvement of more conventional techniques.

Antidepressant drugs as adjuvant analgesics

This article reviews the history of the use of antidepressants in painful states and traces the evolution of thinking from initially considering them as antidepressants to the current concept that they have an analgesic action. The greatest part of this paper considers chronic, nonmalignant, painful states and the evidence with each for the efficacy of some of these drugs. The mechanism of action, pharmacokinetics and adverse effects are discussed. Practical suggestions are made regarding their usage. Although antidepressants are imperfect analgesics because of limited efficacy and untoward effects, they may be the only avenue of relief for a painful condition. The correct choice of agent and proper administration are critical.