Psychomotor performance of patients with rheumatoid arthritis: cross-over comparison of dextropropoxyphene, dextropropoxyphene plus amitriptyline, indomethacin, and placebo

CNS effects of indomethacin: should patients be cautioned about decreased mental alertness and motor coordination?

AIMS

In many European countries as well as in the USA, the leaflet, or even the packaging of indomethacin, contains a specific warning to refrain from activities requiring mental alertness and motor coordination, such as driving a car. In this placebo-controlled randomized study with a crossover design we attempted to find evidence for that warning.

METHODS

Indomethacin 75 mg slow release or a visually identical placebo with similar flavour was taken orally twice daily for 2.5 days. It was suggested that indomethacin affects the motor coordination required to avoid obstacles successfully during walking and that this effect will be even stronger when simultaneously performing a cognitive task that puts mental alertness to the test. Nineteen healthy middle-aged individuals (60 ± 4.7 years, eight female) performed an obstacle avoidance task on a treadmill), combined with a cognitive secondary task. Biceps femoris (BF) muscle response times, obstacle avoidance failure rates and composite scores ((100 × accuracy)/verbal response time) were used to evaluate the data.

RESULTS

No differences between indomethacin and placebo were found on the outcome measures regarding motor coordination, avoidance failure rates (P = 0.81) and BF response times (P = 0.47), nor on the performance on the secondary cognitive task (P = 0.12).

CONCLUSIONS

Even though surrogate methods were used, the current study provides evidence to suggest that there might be no need to caution patients who experience CNS side effects after indomethacin use to avoid activities requiring quick and adequate reactions, such as walking under challenging circumstances and maybe also driving a car.

Opioids in chronic musculoskeletal conditions

The use of opioids for benign disorders has been limited by concerns about these compounds' potential adverse events and their possible misuse. However, during the last few years an increased use in nonmalignant disorders, including rheumatologic diseases, has been observed. Herein, we review the scientific evidence for opioid therapy in three common scenarios in clinical rheumatology. Low back pain is a very frequent reason for consultation. Overall, the large majority of studies show a positive, yet rather moderate, effect of opioids in pain control, as well as in other outcomes including mood, work disability and anxiety. Similarly, opioids seem to have a role in the management of hip and knee osteoarthritis; indeed, they have been included in all international guidelines for the treatment of these conditions. However, clinical studies addressing opioid use in clinical situations are plagued by methodological limitations; furthermore, the large majority of these studies only provide short-term information about opiod utilization in these patients. Finally, opioids are currently being used as complementary therapy in inflammatory joint conditions whereby they may significantly improve the quality of life of some of these patients. Regarding their safety, severe adverse events, including abnormal drug-seeking behaviour, are very rare, but mild adverse events are frequent leading to drug discontinuation in a significant number of cases.

Antidepressants for pain management in rheumatoid arthritis

BACKGROUND

Pain management is a high priority for patients with rheumatoid arthritis (RA). Antidepressants are sometimes used as adjuvant agents to enhance pain relief, help with sleep and reduce depression. Such antidepressants include tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), selective serotonin noradrenaline reuptake inhibitors (SNRIs) and norepinephrine reuptake inhibitors (NRIs). However, the prescription of antidepressants in this population remains controversial because of conflicting scientific evidence.

OBJECTIVES

The aim of this review was to determine the efficacy and safety of antidepressants in pain management in patients with RA.

SEARCH METHODS

We performed a computer assisted search of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, 4th quarter); MEDLINE (1950 to November Week 1, 2010); EMBASE (2010 Week 44); and PsycINFO (1806 to November Week 2, 2010). We also searched the 2008-2009 American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) abstracts and performed a handsearch of reference lists of articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) which compared an antidepressant therapy to another therapy (active or placebo, including non-pharmacological therapies) in adult patients with RA who had at least one clinically relevant outcome measure. Outcomes of interest were pain, adverse effects, function, sleep, depression and quality of life.

DATA COLLECTION AND ANALYSIS

Two blinded review authors independently extracted data and assessed the risk of bias in the trials. We conducted meta-analyses to examine the efficacy of antidepressants on pain, depression and function, as well as their safety.

MAIN RESULTS

We included eight RCTs (652 participants) in this review. All trials evaluated TCAs and two trials evaluated a SSRI as a comparator. Seven of the eight trials had high risk of bias. There was insufficient data for a number needed to treat for an additional beneficial outcome (NNTB) to be calculated for the primary outcome measure of pain. The qualitative analyses found no evidence of an effect of antidepressants on pain intensity or depression in the short-term (less than one week), and conflicting evidence of a medium- (one to six weeks) or long-term (more than six weeks) benefit. There were significantly more minor adverse events in patients receiving TCAs compared with those receiving a placebo (risk ratio (RR) 2.27, 95% confidence interval (CI) 1.17 to 4.42), but there was no significant increase in withdrawals due to an adverse event (RR 1.09, 95% CI 0.49 to 2.42).

AUTHORS' CONCLUSIONS

There is currently insufficient evidence to support the routine prescription of antidepressants as analgesics in patients with RA as no reliable conclusions about their efficacy can be drawn from eight placebo RCTs. The use of these agents may be associated with adverse events which are generally mild and do not lead to cessation of treatment. More high quality trials are needed in this area.

Opioid therapy for treating rheumatoid arthritis pain

BACKGROUND

Despite improvements in the management of rheumatoid arthritis (RA), pain control is often inadequate even when inflammation is well controlled.

OBJECTIVES

To assess the efficacy and safety of opioid analgesics for treating pain in patients with RA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE and EMBASE for studies to May 2010. We also searched the 2008 to 2009 American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts and performed a handsearch of the reference lists of articles.

SELECTION CRITERIA

Studies were included if they were randomized or quasi-randomized controlled trials (RCTs or CCTs) which compared opioid therapy to another therapy (active or placebo) for pain in patients with RA. Outcomes of interest were pain, adverse effects, function and quality of life.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies for inclusion, extracted the data, and performed a risk of bias assessment.

MAIN RESULTS

Eleven studies (672 participants) were included in the review. Four studies assessed the efficacy of single doses of various opioid and non-opioid analgesics; a pooled analysis of these studies was not performed but in each study opioids reduced pain more than placebo. There were no differences between analgesic drugs in these studies.Seven studies were between one and six weeks in duration and assessed six different oral opioids (dextropropoxyphene, codeine, tramadol, tilidine, pentazocine, morphine), either alone or combined with non-opioid analgesics. The only strong opioid investigated was controlled-release morphine sulphate, in a single study with 20 participants. Six studies compared an opioid to placebo. Opioids were superior to placebo in patient-reported global impression of change (3 studies, 324 participants: relative risk (RR) 1.44, 95% CI 1.03 to 2.03) but not for the number of withdrawals due to inadequate analgesia (4 studies, 345 participants: RR 0.82, 95% CI 0.34 to 2.0). Adverse events (most commonly nausea, vomiting, dizziness and constipation) were more frequent in patients receiving opioids compared to placebo (4 studies, 371 participants: odds ratio 3.90, 95% CI 2.31 to 6.56); the pooled risk ratio for withdrawal due to adverse events was 2.67 (3 studies, 331 participants: 95% CI 0.52 to 13.75). One study compared an opioid (codeine with paracetamol) to an NSAID (diclofenac) and found no difference in efficacy or safety between interventions.

AUTHORS' CONCLUSIONS

There is limited evidence that weak oral opioids may be effective analgesics for some patients with RA, but adverse effects are common and may offset the benefits of this class of medications. There is insufficient evidence to draw conclusions regarding the use of weak opioids for longer than six weeks, or the role of strong opioids.

Combination therapy for pain management in inflammatory arthritis (rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, other spondyloarthritis)

BACKGROUND

Despite optimal therapy with disease-modifying antirheumatic drugs, many people with inflammatory arthritis (IA) continue to have persistent pain that may require additional therapy.

OBJECTIVES

To assess the benefits and safety of combination pain therapy for people with IA (rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA) and other spondyloarthritis (SpA)). We planned to assess differences in effects between patients on background disease-modifying antirheumatic drug (DMARD) therapy and patients on no background therapy in subgroup analyses.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); MEDLINE; and EMBASE. We did not impose any date or language restrictions in the search. We also handsearched conference proceedings of the American College of Rheumatology and the European League against Rheumatism (2008-10).

SELECTION CRITERIA

Randomised and controlled clinical trials (RCTs and CCTs) assessing combination therapy (at least two drugs from the following classes: analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), opioids, opioid-like drugs and neuromodulators (antidepressants, anticonvulsants and muscle relaxants)) compared with monotherapy, for adults with IA (RA, AS, PsA and other SpA). We speficically excluded studies that did not report pain or studies without a standardised pain scale as an outcome measure.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed risk of bias and extracted data.

MAIN RESULTS

Twenty-three trials (total of 912 patients) met the inclusion criteria (22 in RA; one in a mixed population of RA and osteoarthritis); all except one were published before 1990. Most study populations were not taking DMARDs (e.g. methotrexate, sulphasalazine, hydroxychloroquine and leflunomide) and all studies were performed prior to the introduction of biologic therapies (e.g. etanercept, infliximab and adalimumab). All trials were at high risk of bias, heterogeneity precluded meta-analysis, and we were only able to report a general description of results.The majority (18 studies, 78%) found no differences between the combination and monotherapy treatments they studied, while five (22%) reported conflicting results, favouring either the combination or monotherapy arms.From the 12 trials on NSAID + analgesic vs NSAID, nine reported no significant difference between the interventions, while three did: in two, the combination therapy achieved better pain control; and the third trial compared combination therapy with two different dosages of monotherapy (NSAID alone) and reported that a high dose phenylbutazone was superior to combination therapy (paracetamol + aspirin), which was superior to low dose phenylbutazone.From the five studies on the combination of two NSAIDS vs one NSAID, four reported no significant differences between interventions, and one reported significantly better pain control with combination therapy.The single trial comparing a combination of opioid + neuromodulator vs opioid reported better pain control with monotherapy.The remaining trials (NSAID + neuromodulator vs NSAID (3 trials); opioid + NSAID vs NSAID (1 trial); and opioid + analgesic vs analgesic (1 trial)) found no significant difference between combination therapy and monotherapy.Information regarding withdrawals due to inadequate analgesia and safety was incompletely reported, but in general there were no differences between combination therapy and monotherapy.No data were available that addressed the value of combination pain therapy or monotherapy for people with IA who have optimal disease suppression. There were no studies that included patients with AS, PsA or SpA.

AUTHORS' CONCLUSIONS

Based on 23 trials, all at high risk of bias, there is insufficient evidence to establish the value of combination therapy over monotherapy for people with IA. Importantly, there are no studies addressing the value of combination therapy for patients with IA who have persistent pain despite optimal disease suppression. Well designed trials are needed to address this question.

Opioid analgesics and the risk of fractures in older adults with arthritis

OBJECTIVES

To compare the risk of fracture associated with initiating opioids with that of nonsteroidal anti-inflammatory drugs (NSAIDs) and the variation in risk according to opioid dose, duration of action, and duration of use.

DESIGN

Retrospective cohort study.

SETTING

Two statewide pharmaceutical benefit programs for persons aged 65 and older.

PARTICIPANTS

Twelve thousand four hundred thirty-six initiators of opioids and 4,874 initiators of NSAIDs began treatment between January 1, 1999, and December 31, 2006. Mean age at initiation of analgesia was 81; 85% of participants were female, and all had arthritis.

MEASUREMENTS

Cox proportional hazards models, adjusted for several potential confounders, quantified fracture risk. Study outcomes were fractures of the hip, humerus or ulna, or wrist, identified using a combination of diagnosis (International Classification of Diseases, Ninth Revision, Clinical Modification) and procedure (Common Procedural Terminology) codes.

RESULTS

There were 587 fracture events among the participants initiating opioids (120 fractures per 1,000 person-years) and 38 fracture events among participants initiating NSAIDs (25 fractures per 1,000 person-years) (hazard ratio (HR)=4.9, 95% confidence interval (CI)=3.5-6.9). Fracture risk was greater with higher opioid dose. Risk was greater for short-acting opioids (HR=5.1, 95% CI=3.7-7.1) than for long-acting opioids (HR=2.6, 95% CI=1.5-4.4), even in participants taking equianalgesic doses, with differential fracture risk apparent for the first 2 weeks after starting opioids but not thereafter.

CONCLUSION

Older people with arthritis who initiate therapy with opioids are more likely to experience a fracture than those who initiate NSAIDs. For the first 2 weeks after initiating opioid therapy, but not thereafter, short-acting opioids are associated with a greater risk of fracture than are long-acting opioids.

Effects of intermediate- and long-term use of opioids on cognition in patients with chronic pain

The authors review research on the intermediate- and long-term effects of taking opioid medication on cognitive functioning in patients with chronic cancer and noncancer pain. Opioids seem to be more likely to worsen cognitive performance during the first few days of use and during the first few hours after a given dose, particularly on timed performance in psychomotor tasks. Results have been inconsistent regarding what decrements in cognitive performance are observed when patients with chronic pain who have been using opioids for more than three days are compared with healthy volunteers. Relatively few differences have been found when cognitive performance in these patients is compared with their performance before taking opioids, or with the performance of a comparable pain population not taking opioids. Major unresolved questions remain regarding such important issues as effects of different types of opioids, dose effects, interactions with other medications, and subject variables.

Measurement of opioid-induced sedation

One of the major side effects of opioid analgesics is sedation. Despite the fact that neither a universal definition nor a gold standard for the measurement of opioid-induced sedation exists, various neurophysiologic and psychomotor measures are used to quantify the sedative effects of opioids. This report reviews the strengths and weaknesses of various approaches that are used to measure opioid-induced sedation. The first section summarizes various neurophysiologic measures (i.e., electroencephalogram, autonomic reflexes, and evoked responses), and the second section reviews psychomotor measures (i.e., visual analog scales, observer assessments, motor performance tests, tests of perceptual processes, tests of information processing, tests of memory, and composite tests) that are used to evaluate the sedative effects of opioids. Implications for future research on opioid-induced sedation are discussed.

Indomethacin and cognitive function in healthy elderly volunteers

1. Cognitive function was studied after single and multiple doses of indomethacin (I) and matched placebo (P) in 20 healthy elderly volunteers using a double-blind crossover design. 2. Arousal, attention, integration, coordination, memory and mood were investigated using a battery of psychomotor tests and the Hospital Anxiety and Depression Scale. Assessments were performed before and after the first and last doses of a 7 day course of medication. 3. Critical flicker fusion threshold fell by a mean of 1.96% on indomethacin compared with a 1.13% rise on placebo 5 h after the first dose (P = 0.029). A beneficial effect on choice reaction time latency (P = 0.012) was seen both after acute and continuing administration of indomethacin. Performance at the most discriminating level (level 3) of the paired word association test was significantly better following 8 days of treatment with indomethacin in the younger (55-65 year-old) age group (P = 0.001). 4. There was no significant difference in performance on the symbol-digit substitution test and the continuous attention task. No change was seen in hospital anxiety and depression scale scores. 5. These results suggest that performance on tests of sensorimotor coordination and short term memory may improve in healthy volunteers following indomethacin administration, whereas tests of attention and psychomotor speed remain unaffected. However, further controlled studies in rheumatic patients are needed to evaluate fully the psychomotor effects of indomethacin and other NSAIDs in clinical practice.

Subjective and behavioral responses to intravenous fentanyl in healthy volunteers

Fentanyl is a mu opiate agonist which is occasionally abused by medical personnel who have ready access to the drug. We examined in healthy volunteers (N = 13) the subjective and psychomotor-impairing effects of intravenous fentanyl (0-100 micrograms/70 kg). A randomized, placebo-controlled, crossover design was used in which subjects were injected with 0, 25 (N = 6), 50 and 100 micrograms/70 kg fentanyl in a double-blind fashion. Subjects completed several questionnaires commonly used in abuse liability testing studies before drug injection and at periodic intervals for up to 3 h after drug injection. Subjects also completed several psychomotor tests at these times. Some aspects of psychomotor functioning (e.g., eye-hand coordination) were impaired by fentanyl. Fentanyl produced dose-related increases in ratings of "high" and "sedated," but also tended to produce dysphoria and somatic symptomatology. Most subjects reported liking the effects of the two higher doses of fentanyl for at least a brief time after injection, but they varied widely in their linking ratings across the 3-h post-drug injection period. Despite the transient increases in liking ratings, fentanyl did not increase scores on a widely-used measure of drug-induced euphoria (morphine-benzedrine group scale of the Addiction Research Center Inventory). The present results suggest that some medical personnel who experiment with fentanyl may like it, and thus be at increased risk for abusing the drug in the future.

Psychomotor, respiratory and neuroendocrinological effects of a mu-opioid receptor agonist (oxycodone) in healthy volunteers

Psychomotor performance related to driving and occupational skills was measured double-blind and cross-over in 9 healthy volunteers before and 1.5, 3 and 4.5 hr after intramuscular injection of oxycodone (0.13 mg/kg), oral diphenhydramine (100 mg) and placebo. The effects of oxycodone on performance peaked at 1.5 hr when it prolonged reaction time and impaired vigilance, attention, body balance and coordination of extraocular muscles. The subjects assessed themselves mentally slow, muzzy and impaired by performance on visual analogue scales still 3 hr after injection. Critical flicker discrimination was impaired and some respiratory depression still present at 4.5 hr after administration. Oxycodone elevated plasma prolactin at 1.5 and 3 hr while growth hormone levels remained unaffected. We conclude that the profile of psychomotor decrement produced by this mu-opioid agonist closely resembles that of agonist-antagonist analgesics.