Risk for fractures with centrally acting muscle relaxants: an analysis of a national Medicare Advantage claims database

Does adding muscle relaxant make post-operative pain better? a narrative review of the literature from US and European studies

Centrally acting skeletal muscle relaxants (CASMR) are widely prescribed as adjuncts for acute and chronic pain. Given the recent interest in multimodal analgesia and reducing opioid consumption, there has been an increase in its use for perioperative/postoperative pain control. The mechanism of action, pharmacodynamics, and pharmacokinetics of these drugs vary. Their use has been studied in a wide range of operative and non-operative settings. The best evidence for the efficacy of CASMRs is in acute, nonoperative musculoskeletal pain and, in the operative setting, in patients undergoing total knee arthroplasty and abdominal surgery, including inguinal herniorrhaphy and hemorrhoidectomy. The risk of complications and side effects, coupled with the limited evidence of efficacy, should prompt careful consideration of individual patient circumstances when prescribing CASMRs as part of perioperative pain management strategies.

Secondary fracture rates and risk factors 1 year after a proximal femoral fracture under FLS

INTRODUCTION

We aimed to investigate the secondary fracture rates and risk factors in patients with proximal femoral fractures using fracture liaison service (FLS) during the coronavirus disease (COVID)-19 pandemic.

MATERIALS AND METHODS

In this multi-center prospective cohort study, patients with proximal femoral fractures who were treated surgically at three hospitals from April 2020 to March 2021 were included. Follow-up examinations at 6 and 12 months postoperatively were conducted to investigate the clinical data and ascertain whether osteoporosis treatment could be continued.

RESULTS

A total of 316 patients with proximal femoral fractures were registered. During the follow-up period, 17 patients died and 67 patients could not visit the hospitals owing to the COVID-19 pandemic. In total, 172 patients who could be followed-up 12 months postoperatively were examined using dual-energy X-ray absorptiometry during hospitalization; underwent postoperative osteoporosis treatment, mainly with bisphosphonates (89.5%); and were administered medications continuously. Secondary fractures occurred within 1 year in 14 patients (8.1%). Multivariate analysis showed that patients who used sleeping pills and had a lower functional independence measure had an increased risk for developing secondary fractures.

CONCLUSION

During the COVID-19 pandemic, secondary fractures can be prevented if the patients can be followed and osteoporosis treatment can be continued. Conversely, despite adequate osteoporosis drug examination and treatment, a certain number of secondary fractures still occurred. The finding that postoperative osteoporosis therapy using routine medications and rehabilitation is associated with secondary fractures may support the importance of establishing clinical standards consisting of a multidisciplinary collaboration for FLS.

Skeletal muscle relaxant drug-drug-drug interactions and unintentional traumatic injury: Screening to detect three-way drug interaction signals

AIM

The aim of this study was to identify skeletal muscle relaxant (SMR) drug-drug-drug interaction (3DI) signals associated with increased rates of unintentional traumatic injury.

METHODS

We conducted automated high-throughput pharmacoepidemiologic screening of 2000-2019 healthcare data for members of United States commercial and Medicare Advantage health plans. We performed a self-controlled case series study for each drug triad consisting of an SMR base-pair (i.e., concomitant use of an SMR with another medication), and a co-dispensed medication (i.e., candidate interacting precipitant) taken during ongoing use of the base-pair. We included patients aged ≥16 years with an injury occurring during base-pair-exposed observation time. We used conditional Poisson regression to calculate adjusted rate ratios (RRs) with 95% confidence intervals (CIs) for injury with each SMR base-pair + candidate interacting precipitant (i.e., triad) versus the SMR-containing base-pair alone.

RESULTS

Among 58 478 triads, 29 were significantly positively associated with injury; confounder-adjusted RRs ranged from 1.39 (95% CI = 1.01-1.91) for tizanidine + omeprazole with gabapentin to 2.23 (95% CI = 1.02-4.87) for tizanidine + diclofenac with alprazolam. Most identified 3DI signals are new and have not been formally investigated.

CONCLUSION

We identified 29 SMR 3DI signals associated with increased rates of injury. Future aetiologic studies should confirm or refute these SMR 3DI signals.

Signals of Muscle Relaxant Drug Interactions Associated with Unintentional Traumatic Injury: A Population-Based Screening Study

BACKGROUND

Use of muscle relaxants is rapidly increasing in the USA. Little is understood about the role of drug interactions in the known association between muscle relaxants and unintentional traumatic injury, a clinically important endpoint causing substantial morbidity, disability, and death.

OBJECTIVE

We examined potential associations between concomitant drugs (i.e., precipitants) taken with muscle relaxants (affected drugs, i.e., objects) and hospital presentation for unintentional traumatic injury.

METHODS

In a series of self-controlled case series studies, we screened to identify drug interaction signals for muscle relaxant + precipitant pairs and unintentional traumatic injury. We used Optum's de-identified Clinformatics^® Data Mart Database, 2000-2019. We included new users of a muscle relaxant, aged 16-90 years, who were dispensed at least one precipitant drug and experienced an unintentional traumatic injury during the observation period. We classified each observation day as precipitant exposed or precipitant unexposed. The outcome was an emergency department or inpatient discharge diagnosis for unintentional traumatic injury. We used conditional Poisson regression to estimate rate ratios adjusting for time-varying confounders and then accounted for multiple estimation via semi-Bayes shrinkage.

RESULTS

We identified 74,657 people who initiated muscle relaxants and experienced an unintentional traumatic injury, in whom we studied concomitant use of 2543 muscle relaxant + precipitant pairs. After adjusting for time-varying confounders, 16 (0.6%) pairs were statistically significantly and positively associated with injury, and therefore deemed signals of a potential drug interaction. Among signals, semi-Bayes shrunk, confounder-adjusted rate ratios ranged from 1.29 (95% confidence interval 1.04-1.62) for baclofen + sertraline to 2.28 (95% confidence interval 1.14-4.55) for methocarbamol + lamotrigine.

CONCLUSIONS

Using real-world data, we identified several new signals of potential muscle relaxant drug interactions associated with unintentional traumatic injury. Only one among 16 signals is currently reported in a major drug interaction knowledge base. Future studies should seek to confirm or refute these signals.

Assessment of Physician Prescribing of Muscle Relaxants in the United States, 2005-2016

IMPORTANCE

Little is known to date about national trends in the prescribing of skeletal muscle relaxants (SMRs), the use of which is associated with important safety concerns, especially in older adults and in those who use concomitant opioids.

OBJECTIVE

To measure national trends in SMR prescribing over a 12-year period.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the National Ambulatory Medical Care Survey from January 2005 to December 2016. Data were analyzed from August 21, 2018, to July 18, 2019. The study included patients with ambulatory care visits who had encounters with non-federally funded, office-based physicians in the United States.

EXPOSURES

SMR use, categorized as newly prescribed or continued therapy at the office visit.

MAIN OUTCOMES AND MEASURES

Ambulatory care visits-overall and stratified by calendar year, geographic region, and patient age, sex, and race-in which an SMR was newly prescribed or continued were quantified. Among office visits in which an SMR was newly prescribed, diagnoses were assessed. Concomitant medications were quantified for all office visits, stratified by new or continued therapy. Survey visit weights were used to estimate nationally representative measures, and age-standardized rates were generated by geographic region using US Census data.

RESULTS

This study included a total of 314 970 308 office visits (mean [SD] age, 53.5 [15.2] years; 194 621 102 [61.8%] men and 120 349 206 [38.2%] women). In 2016, there were 30 730 262 (95% CI, 30 626 464-30 834 060) US ambulatory care visits in which an SMR was either newly prescribed or continued as ongoing therapy. Patients in these visits were most frequently female (58.2% [95% CI, 57.9%-58.6%]), white (53.7% [95% CI, 53.4%-54.0%]), and aged 45 to 64 years (48.5% [95% CI, 48.2%-48.9%]). During the study period, office visits with a prescribed SMR nearly doubled from 15.5 million (95% CI, 15.4-15.6 million) in 2005 to 30.7 million (95% CI, 30.6-30.8 million) in 2016. Although visits for new SMR prescriptions remained stable, office visits with continued SMR drug therapy tripled from 8.5 million (95% CI, 8.4-8.5 million) visits in 2005 to 24.7 million (95% CI, 24.6-24.8 million) visits in 2016. Older adults accounted for 22.2% (95% CI, 21.8%-22.6%) of visits with an SMR prescription. Concomitant use of an opioid was recorded in 67.2% (95% CI, 62.0%-72.5%) of all visits with a continuing SMR prescription.

CONCLUSIONS AND RELEVANCE

This study found that SMR use increased rapidly between 2005 and 2016, which is a concern given the prominent adverse effects and limited long-term efficacy data associated with their use. These findings suggest that approaches are needed to limit the long-term use of SMRs, especially in older adults, similar to approaches to limit long-term use of opioids and benzodiazepines.

Sodium-glucose co-transporter 2 inhibitors and the risk of fractures: A propensity score-matched cohort study

PURPOSE

To determine the risk of fractures associated with sodium-glucose co-transporter 2 inhibitors (SGLT2i) compared with dipeptidyl peptidase-4 inhibitors (DPP4i).

METHODS

We conducted a retrospective cohort study using data from the Truven Health MarketScan (2009-2015) databases. Our cohort included patients newly initiating treatment with SGLT2i or DPP-4i between 1 April 2013 and 31 March 2015 that were matched 1:1 using high dimensional propensity scores. Patients were followed up in an as-treated approach starting from initiation of treatment until the earliest of any fracture, treatment discontinuation, disenrollment, or end of data (31 December 2015). Risk of fractures was determined at any time during the follow-up, early in therapy (1-14 days of the follow-up), and later in therapy (15 days and beyond). Cox proportional hazards models were used to determine hazard ratios and robust 95% confidence intervals (95% CI).

RESULTS

After matching, our cohort included 30 549 patients in each treatment group. Over a median follow-up of 219 days, there were 745 fractures overall. The most common site for fractures was the foot (32.7%). The effect estimates for fracture risk occurring at any time during follow-up, early in therapy, and later in therapy were HR 1.11 [95% CI 0.96-1.28], HR 1.82 [95% CI 0.99-3.32], and HR 1.07 [95% CI 0.92-1.24], respectively.

CONCLUSION

There is a possible increase in risk for fractures early in therapy with SGLT2i. Beyond this initial period, SGLT2is had no apparent effect on the incidence of fractures.

Muscle Relaxant Use Among Hemodialysis Patients: Prevalence, Clinical Indications, and Adverse Outcomes

RATIONALE & OBJECTIVE

Muscle relaxants are often used to treat musculoskeletal pain or cramping, which are commonly experienced by hemodialysis patients. However, the extent to which muscle relaxants are prescribed in this population and the risks associated with their use have not been characterized.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

140,899 Medicare-covered adults receiving hemodialysis in 2011, identified in the US Renal Data System.

EXPOSURE

Time-varying muscle relaxant exposure.

OUTCOMES

Primary outcomes were time to first emergency department visit or hospitalization for altered mental status, fall, or fracture. Secondary outcomes were death and composites of death with each of the primary outcomes.

ANALYTICAL APPROACH

Multivariable Cox regression analysis.

RESULTS

10% of patients received muscle relaxants in 2011. 11%, 6%, 3%, and 13% had an episode of altered mental status, fall, fracture, and death, respectively. Muscle relaxant use was associated with higher risk for altered mental status (HR, 1.39; 95% CI, 1.29-1.51) and fall (HR, 1.18; 95% CI, 1.05-1.33) compared to no use. Muscle relaxant use was not statistically significantly associated with higher risk for fracture (HR, 1.17; 95% CI, 0.98-1.39). Muscle relaxant use was associated with lower hazard of death (HR, 0.85; 95% CI, 0.76-0.94). However, hazards were higher for altered mental status or death (HR, 1.17; 95% CI, 1.10-1.25), fall or death (HR, 1.14; 95% CI, 1.06-1.22), and fracture or death (HR, 1.10; 95% CI, 1.01-1.20).

LIMITATIONS

A causal association between muscle relaxant use and outcomes cannot be inferred, and residual confounding cannot be excluded. Exposure and outcomes were ascertained using administrative claims.

CONCLUSIONS

Muscle relaxant use was common in hemodialysis patients and associated with altered mental status and falls. We could not rule out a clinically meaningful association between muscle relaxant use and fracture. The lower risk for death with muscle relaxants may have been the result of residual confounding. Future research to define the appropriate use of muscle relaxants in this population is warranted.

Benzodiazepines, Z-drugs and the risk of hip fracture: A systematic review and meta-analysis

Background

Hip fractures in the older person lead to an increased risk of mortality, poorer quality of life and increased morbidity. Benzodiazepine (BNZ) use is associated with increased hip fracture rate, consequently Z-drugs are fast becoming the physician’s hypnotic prescription of choice yet data on their use is limited. We compared the risk of hip fracture associated with Z-drugs and BNZ medications, respectively, and examined if this risk varied with longer-term use.

Methods and findings

We carried out a systematic review of the literature and meta-analysis. MEDLINE and SCOPUS were searched to identify studies involving BNZ or Z-drugs and the risk of hip fracture up to May 2015. Each included study was quality-assessed. A pooled relative risk of hip fracture was calculated using the generic inverse variance method, with a random effects model, with the length of hypnotic usage as a subgroup. Both BNZ, and Z-drug use respectively, were significantly associated with an increased risk of hip fracture (RR = 1.52, 95% CI 1.37–1.68; and RR = 1.90, 95% CI 1.68–2.13). Short-term use of BNZ and Z-drugs respectively, was also associated with the greatest risk of hip fracture (RR = 2.40, 95% CI 1.88–3.05 and RR = 2.39, 95% CI 1.74–3.29).

Conclusions

There is strong evidence that both BNZ and Z-drugs are associated with an increased risk of hip fracture in the older person, and there is little difference between their respective risks. Patients newly prescribed these medicines are at the greatest risk of hip fracture. Clinicians and policy makers need to consider the increased risk of fallings and hip fracture particularly amongst new users of these medications.

Risk of injury associated with skeletal muscle relaxant use in older adults

BACKGROUND

The use of skeletal muscle relaxants (SMRs) among older adults is associated with sedation and confusion, which may lead to an increased risk of falls and injuries. SMRs continue to be used among older adults, although they are on the Beers list as drugs to avoid in the elderly.

OBJECTIVE

To investigate the relationship between SMR use and subsequent risk of injury.

METHODS

This was a retrospective case-control study of members aged 65 years or older enrolled in an integrated health care system. Cases were defined as patients with a documented injury resulting in either a hospitalization or an emergency department or urgent care visit from January 2009 through December 2010. Cases were matched to controls in a 1:4 ratio by age and sex. Patients had to be enrolled and alive on the date of an injury (index date). SMR exposure for all cases and controls was evaluated within 60 days prior to the index date. Conditional logistic regression adjusted for covariates was performed, with risk estimates presented as odds ratios with 95% confidence intervals.

RESULTS

From a base population of 322,806 older adults, we identified 27,974 cases of injury and 104,303 matched controls. Among the cases, 365 (1.30%) used an SMR; among the controls, 801 (0.77%) used an SMR in the 60 days prior to the index date. After adjustment for demographic and clinical covariates, risk of injury was significantly increased for patients using an SMR compared to no use (OR 1.32, 95% CI 1.16-1.50; p < 0.001). Carisoprodol was associated with an increased risk of injury (OR 1.73, 95% CI 1.04-2.88; p = 0.036), as were methocarbamol (OR 1.42, 95% CI 1.16-1.75; p = 0.001) and cyclobenzaprine (OR 1.22, 95% CI 1.02-1.45; p = 0.029).

CONCLUSIONS

Older adults using SMRs have an increased risk of injury. These findings provide evidence to support current recommendations to avoid the use of SMRs in elderly patients.

Psychotropic drug-induced falls in older people: a review of interventions aimed at reducing the problem

Falls are a common health problem for older people, and psychotropic medications have been identified as an important independent fall risk factor. The objective of this paper was to review the literature relating to the effect of psychotropic medications on falls in older people, with a particular focus on evidence supporting minimization of their use to reduce risk of falls. A literature search identified 18 randomized trials meeting the inclusion criteria for the review of effectiveness of psychotropic medication withdrawal studies, including four with falls outcomes. One of these, which targeted reduced psychotropic medication use in the community, reported a 66% reduction in falls, while the other studies demonstrated some success in reducing psychotropic medication use but with mixed effects on falls. Other randomized trials evaluated various approaches to reducing psychotropic medications generally or specific classes of psychotropic medications (e.g. benzodiazepines), but did not report fall-related outcomes. Overall, these studies reported moderate success in reducing psychotropic medication use, and a number reported no or limited worsening of key outcomes such as sleep quality or behavioural difficulties associated with withdrawal of psychotropic medication use. Reduced prescription of psychotropic medications (e.g. seeking non-pharmacological alternatives to their use in place of prescription in the first place or, for those patients for whom these medications are deemed necessary, regular monitoring and efforts to cease use or wean off use over time) needs to be a strong focus in clinical practice for three reasons. Firstly, psychotropic medications are commonly prescribed for older people, both in the community and especially in the residential care setting, and their effectiveness in a number of clinical groups has been questioned. Secondly, there is strong evidence of an association between substantially increased risk of falls and use of a number of psychotropic medications, including benzodiazepines (particularly, the long-acting agents), antidepressants and antipsychotic drugs. Finally, the largest effect of any randomized trial of falls prevention to date was achieved with a single intervention consisting of weaning psychotropic drug users off their medications.

Design considerations, architecture, and use of the Mini-Sentinel distributed data system

PURPOSE

We describe the design, implementation, and use of a large, multiorganizational distributed database developed to support the Mini-Sentinel Pilot Program of the US Food and Drug Administration (FDA). As envisioned by the US FDA, this implementation will inform and facilitate the development of an active surveillance system for monitoring the safety of medical products (drugs, biologics, and devices) in the USA.

METHODS

A common data model was designed to address the priorities of the Mini-Sentinel Pilot and to leverage the experience and data of participating organizations and data partners. A review of existing common data models informed the process. Each participating organization designed a process to extract, transform, and load its source data, applying the common data model to create the Mini-Sentinel Distributed Database. Transformed data were characterized and evaluated using a series of programs developed centrally and executed locally by participating organizations. A secure communications portal was designed to facilitate queries of the Mini-Sentinel Distributed Database and transfer of confidential data, analytic tools were developed to facilitate rapid response to common questions, and distributed querying software was implemented to facilitate rapid querying of summary data.

RESULTS

As of July 2011, information on 99,260,976 health plan members was included in the Mini-Sentinel Distributed Database. The database includes 316,009,067 person-years of observation time, with members contributing, on average, 27.0 months of observation time. All data partners have successfully executed distributed code and returned findings to the Mini-Sentinel Operations Center.

CONCLUSION

This work demonstrates the feasibility of building a large, multiorganizational distributed data system in which organizations retain possession of their data that are used in an active surveillance system.

Year in review: medication mishaps in the elderly

OBJECTIVE

This paper reviews articles from 2010 that examined medication mishaps (ie, medication errors and adverse drug events [ADEs]) in the elderly.

METHODS

The MEDLINE and EMBASE databases were searched for English-language articles published in 2010 using a combination of search terms including medication errors, medication adherence, medication compliance, suboptimal prescribing, monitoring, adverse drug events, adverse drug withdrawal events, therapeutic failures, and aged. A manual search of the reference lists of the identified articles and the authors' article files, book chapters, and recent reviews was conducted to identify additional publications. Five studies of note were selected for annotation and critique. From the literature search, this paper also generated a selected bibliography of manuscripts published in 2010 (excluding those previously published in the American Journal of Geriatric Pharmacotherapy or by one of the authors) that address various types of medication errors and ADEs in the elderly.

RESULTS

Three studies focused on types of medication errors. One study examined underuse (due to prescribing) as a type of medication error. This before-and-after study from the Netherlands reported that those who received comprehensive geriatric assessments had a reduction in the rate of undertreatment of chronic conditions by over one third (from 32.9% to 22.3%, P < 0.05). A second study focused on reducing medication errors due to the prescribing of potentially inappropriate medications. This quasi-experimental study found that a computerized provider order entry clinical decision support system decreased the number of potentially inappropriate medications ordered for patients ≥ 65 years of age who were hospitalized (11.56 before to 9.94 orders per day after, P < 0.001). The third medication error study was a cross-sectional phone survey of managed-care elders, which found that more blacks than whites had low antihypertensive medication adherence as per a self-reported measure (18.4% vs 12.3%, respectively; P < 0.001). Moreover, blacks used more complementary and alternative medicine (CAM) than whites for the treatment of hypertension (30.5% vs 24.7%, respectively; P = 0.005). In multivariable analyses stratified by race, blacks who used CAM were more likely than those who did not to have low antihypertensive medication adherence (prevalence rate ratio = 1.56; 95% CI, 1.14-2.15; P = 0.006). The remaining two studies addressed some form of medication-related adverse patient events. A case-control study of Medicare Advantage patients revealed for the first time that the use of skeletal muscle relaxants was associated significantly with an increased fracture risk (adjusted odds ratio = 1.40; 95% CI, 1.15-1.72; P < 0.001). This increased risk was even more pronounced with the concomitant use of benzodiazepines. Finally, a randomized controlled trial across 16 centers in France used a 1-week educational intervention about high-risk medications and ADEs directed at rehabilitation health care teams. Results indicated that the rate of ADEs in the intervention group was lower than that in the usual care group (22% vs 36%, respectively, P = 0.004).

CONCLUSION

Information from these studies may advance health professionals' understanding of medication errors and ADEs and may help guide research and clinical practices in years to come.

Trends in use of high-risk medications for older veterans: 2004 to 2006

OBJECTIVES

To examine the change in use of high-risk medications for the elderly (HRME), as defined by the National Committee on Quality Assurance's Healthcare Effectiveness Data and Information Set (HEDIS) quality measure (HEDIS HRME), by older outpatient veterans over a 3-year period and to identify risk factors for HEDIS HRME exposure overall and for the most commonly used drug classes.

DESIGN

Longitudinal retrospective database analysis.

SETTING

Outpatient clinics within the Department of Veterans Affairs (VA).

PARTICIPANTS

Veterans aged 65 by October 1, 2003, and who received VA care at least once each year until September 30, 2006.

MEASUREMENTS

Rates of use of HEDIS HRME overall and according to specific drug classes each year from fiscal year 2004 (FY04) to FY06.

RESULTS

In a cohort of 1,567,467, high-risk medication exposure fell from 13.1% to 12.3% between FY04 and FY06 (P<.001). High-risk antihistamines (e.g., diphenhydramine), opioid analgesics (e.g., propoxyphene), skeletal muscle relaxants (e.g., cyclobenzaprine), psychotropics (e.g., long half-life benzodiazepines), endocrine (e.g., estrogen), and cardiac medications (e.g., short-acting nifedipine) had modest but statistically significant (P<.001) reductions (range -3.8% to -16.0%); nitrofurantoin demonstrated a statistically significant increase (+36.5%; P<.001). Overall HEDIS HRME exposure was more likely for men, Hispanics, those receiving more medications, those with psychiatric comorbidity, and those without prior geriatric care. Exposure was lower for individuals exempt from copayment. Similar associations were seen between ethnicity, polypharmacy, psychiatric comorbidity, access-to-care factors, and use of individual HEDIS HRME classes.

CONCLUSION

HEDIS HRME drug exposure decreased slightly in an integrated healthcare system. Risk factors for exposure were not consistent across drug groups. Future studies should examine whether interventions to further reduce HEDIS HRME use improve health outcomes.

Pimavanserin tartrate, a 5-HT(2A) receptor inverse agonist, increases slow wave sleep as measured by polysomnography in healthy adult volunteers

OBJECTIVE

Determine the effects of pimavanserin tartrate [ACP-103; N-(4-flurophenylmethyl)-N-(1-methylpiperidin-4-yl)-N'-(4-(2-methylpropyloxy)phenylmethyl)carbamide], a selective serotonin 5-HT(2A) receptor inverse agonist, on slow wave sleep (SWS), other sleep parameters, and attention/vigilance.

METHODS

Forty-five healthy adults were randomized to pimavanserin (1, 2.5, 5, or 20 mg) or placebo in a double-blind fashion (n=9/group). Pimavanserin or placebo was administered once daily in the morning for 13 consecutive days. The effects of pimavanserin were measured after the first dose and again after 13 days. Sleep parameters were measured by polysomnography. Effects on attention/vigilance were measured by a continuous performance task.

RESULTS

Compared to placebo, pimavanserin significantly increased SWS following single and multiple dose administration. Pimavanserin also decreased number of awakenings. PSG variables not affected by pimavanserin included sleep period time, total sleep time, sleep onset latency, number of stage shifts, total time awake, early morning wake, and microarousal index. Changes in sleep architecture parameters, sleep profile parameters, and spectral power density parameters were consistent with a selective increase in SWS. Pimavanserin did not adversely affect performance on the continuous performance test measured in the evening before or morning after polysomnography.

CONCLUSIONS

These data suggest that pimavanserin selectively increases slow wave sleep and decreases awakenings, an effect that does not diminish with repeated administration.