Modafinil treatment of opioid-induced sedation

Knowledge Gaps in the Perioperative Management of Adults With Narcolepsy: A Call for Further Research

There is increasing awareness that sleep disorders may be associated with increased perioperative risk. The Society of Anesthesia and Sleep Medicine created the Narcolepsy Perioperative Task Force: (1) to investigate the current state of knowledge of the perioperative risk for patients with narcolepsy, (2) to determine the viability of developing perioperative guidelines for the management of patients with narcolepsy, and (3) to delineate future research goals and clinically relevant outcomes. The Narcolepsy Perioperative Task Force established that there is evidence for increased perioperative risk in patients with narcolepsy; however, this evidence is sparse and based on case reviews, case series, and retrospective reviews. Mechanistically, there are a number of potential mechanisms by which patients with narcolepsy could be at increased risk for perioperative complications. These include aggravation of the disease itself, dysautonomia, narcolepsy-related medications, anesthesia interactions, and withdrawal of narcolepsy-related medications. At this time, there is inadequate research to develop an expert consensus or guidelines for the perioperative management of patients with narcolepsy. The paucity of available literature highlights the critical need to determine if patients with narcolepsy are at an increased perioperative risk and to establish appropriate research protocols and clearly delineated patient-centered outcomes. There is a real need for collaborative research among sleep medicine specialists, surgeons, anesthesiologists, and perioperative providers. This future research will become the foundation for the development of guidelines, or at a minimum, a better understanding how to optimize the perioperative care of patients with narcolepsy.

Nonpeptide Orexin-2 Receptor Agonist Attenuates Morphine-induced Sedative Effects in Rats

BACKGROUND

Sleepiness and decrease in attention are dose-limiting side effects of opioids. The orexin/hypocretin system plays an important role in maintaining wakefulness. This study aimed to explore the potential of a nonpeptide orexin receptor agonist to alleviate morphine-induced sedative effects.

METHODS

Morphine sedative effects were evaluated as changes in electroencephalogram (EEG), locomotor activity, and acoustic startle response in rats (n = 5 to 9 per group). Effects of intracerebroventricular orexin-A and systemic orexin type-2 receptor agonist, YNT-185, on EEG changes induced by morphine were examined. Furthermore, the authors examined effects of morphine administered with or without YNT-185 on locomotor activity and on acoustic startle response.

RESULTS

Morphine-induced, frequent, short epochs of increased power (total epoch duration: 0.5 [0.0 to 8.0] s/10 min during baseline vs. 74.0 [49.0 to 115.0] s/10 min during the post-morphine administration period; P = 0.012). EEG analyses revealed that morphine-induced, high-amplitude, slow activity (increase in spectral power of frequencies less than 15 Hz, baseline vs. postmorphine; P < 0.001). Orexin-A and YNT-185 attenuated these changes. Locomotor activity decreased after morphine (268 [103 to 889] ambulatory movement counts during baseline period [20 min] vs. 138 [7 to 434] counts during 40 to 59 min postadministration; P = 0.012), but did not change after morphine with YNT-185 (363 [121 to 636] vs. 864 [381 to 1092] counts, difference within morphine + YNT-185 group; P = 0.071). Startle response latency was longer after morphine (26 [20 to 28] ms) than after morphine with YNT-185 (17 [16 to 18] ms; P = 0.012).

CONCLUSIONS

Orexin-A and/or YNT-185 attenuated morphine-induced sedative effects assessed by EEG changes and behavioral measures in rats. The authors' results suggest that orexin-2 receptor activation alleviates morphine-induced sedative effects.

Effect of Modafinil on Cognitive Function in Intensive Care Unit Patients: A Retrospective Cohort Study

Modafinil therapy, a nonamphetamine cognition-enhancing agent, holds the potential to improve recovery from cognitive impairment after intensive care unit (ICU) admission. To date, however, there is a paucity of data on modafinil use in the ICU setting. The purpose of this study was to explore the role of modafinil for improvement in cognition in ICU patients. This retrospective cohort study evaluated a total of 60 ICU patients with any ventilatory support who started on modafinil during their ICU stay from January 1, 2010, to March 19, 2016. The requirements of opioids and sedatives, as well as the lowest and average scores of the Glasgow Coma Scale (GCS) and Riker Sedation-Agitation Scale (SAS), were recorded during 48 hours before and after the start of modafinil therapy in 6-hour periods. The average daily modafinil dose of 170 mg was given for a median duration of 9 days. Modafinil administration was associated with a small, nonsignificant increase in GCS by 0.34 points after controlling for age, baseline severity of illness, and changes in sedation and analgesia over time (95%CI, -0.34 to 0.73 points; P = .0743). No major modafinil-associated adverse effects were observed. Modafinil administration did not significantly improve cognitive function in ICU patients within 48 hours of initiation. However, because of lack of robust evidence, the impact of modafinil on overall patient outcomes in the ICU remains unclear and needs further investigation.

Opioid-induced Hallucinations: A Review of the Literature, Pathophysiology, Diagnosis, and Treatment

Despite their association with multiple adverse effects, opioid prescription continues to increase. Opioid-induced hallucination is an uncommon yet significant adverse effect of opioid treatment. The practitioner may encounter patient reluctance to volunteer the occurrence of this phenomenon because of fears of being judged mentally unsound. The majority of the literature concerning opioid-induced hallucinations arises from treatment during end-of-life care and cancer pain. Because the rate of opioid prescriptions continues to increase in the population, the rate of opioid-associated hallucinations may also conceivably increase. With a forecasted increase in the patient-to-physician ratio, opioid therapy is predicted to be provided by practitioners of varying backgrounds and medical specialties. Hence, knowledge of the pharmacology and potential adverse effects of these agents is required. This review seeks to increase awareness of this potential complication through a discussion of the literature, potential mechanisms of action, diagnosis, and treatment strategies.

The Basic Pharmacology of Opioids Informs the Opioid Discourse about Misuse and Abuse: A Review

Morphine and other opioids are widely used to manage moderate to severe acute pain syndromes, such as pain associated with trauma or postoperative pain, and they have been used to manage chronic pain, even chronic nonmalignant pain. However, recent years have seen a renewed recognition of the potential for overuse, misuse, and abuse of opioids. Therefore, prescribing opioids is challenging for healthcare providers in that clinical effectiveness must be balanced against negative outcomes-with the possibility that neither are achieved perfectly. The current discourse about the dual 'epidemics' of under-treatment of legitimate pain and the over-prescription of opioids is clouded by inadequate or inaccurate understanding of opioid drugs and the endogenous pain pathways with which they interact. An understanding of the basic pharmacology of opioids helps inform the clinician and other stakeholders about these simultaneously under- and over-used agents.

Perioperative risks of narcolepsy in patients undergoing general anesthesia: A case-control study

STUDY OBJECTIVE

To compare the perioperative outcomes between patients with narcolepsy and matched controls undergoing anesthetic management.

DESIGN

Retrospective 2:1 matched study design.

SETTING

Large tertiary medical center.

PATIENTS

Narcoleptic patients who underwent general anesthesia from January 1, 2011, through September 30, 2015, were matched with controls by age, sex, and type and year of surgery.

MEASUREMENTS

Medical records were reviewed for episodes of respiratory depression during phase I recovery and for other meaningful perioperative outcomes.

MAIN RESULTS

The perioperative courses of 76 narcoleptic patients and their controls were examined. Compared to controls, narcoleptic patients were more often prescribed central nervous system stimulants (73.7% vs 4.0%, P<0.001) and antidepressants (46.1% vs 27.6%, P=0.007) and more often had obstructive sleep apnea (40.8% vs 19.1%, P<0.001). The intraoperative course was similar. The number of episodes of respiratory depression was not different between patients and controls (5 [6.6%] vs 12 [7.9%], respectively; P=0.80). Narcoleptic patients had a higher frequency of emergency response team activations (5 of 76 [6.6%]; 95% CI, 2.2%-14.7%) compared to controls (2 of 152 [1.3%]; 95% CI, 0.2%-4.7%) (P=0.04). Hemodynamic instability was the indication for all emergency response team activations except 1, which was for a narcoleptic patient who had excessive postoperative sedation and respiratory depression.

CONCLUSIONS

Narcoleptic patients had similar intraoperative courses as the matched controls, including phase I anesthetic recovery. However, they had a higher rate of emergency response team activations than the controls, which suggests that patients with narcolepsy may be at increased perioperative risk.

Cognitive Effects and Sedation

OBJECTIVE

Cognitive effects and sedation (CES) are prevalent in chronic nonmalignant pain populations receiving long-term opioid therapy and are among the most common reasons patients discontinue opioid use. In this narrative review, we describe the phenomenology, epidemiology, mechanisms, assessment, and management of opioid-related CES.

DESIGN

We reviewed the empirical and theoretical literature on CES in opioid-treated populations with chronic pain. Data on long-term opioid therapy (≥ 3 months in duration) in chronic nonmalignant pain patients were sought.

RESULTS

The phenomenology of CES includes: inattention, concentration difficulties, memory deficits, psychomotor dysfunction, perceptual distortions, and executive dysfunction and somnolence, sleep disorders, and lethargy. Deficits may be caused by unrelieved pain or opioid therapy alone, or from a combination of these and other factors. Mechanisms include central nervous system effects, for example, direct toxic effects on neurons resulting in decreased consciousness; direct effects on processing and reaction resulting in cognitive or psychomotor impairment, and inhibitory effects on cholinergic activity. Pharmacological management approaches may include opioid dose reduction and rotation or psychostimulant use. Nonpharmacological approaches may include cognitive-behavioral therapy, mindfulness-based stress reduction, acupuncture, exercise, and yoga.

CONCLUSIONS

The most prevalent CES include: memory deficits (73-81%), sleep disturbance (35-57%), and fatigue (10%). At its most severe, extreme cognitive dysfunction can result in frank delirium and decreased alertness can result in coma. Emotional distress, sleep disorders, and other comorbidities and treatments can worsen CES, particularly among the elderly. Conclusions about the neuropsychological domains affected by opioids are limited due to the heterogeneity of studies and methodological issues.

The Use of Modafinil in the Intensive Care Unit

As patients recover from their critical illness, the focus of intensive care unit (ICU) care becomes rehabilitation. Fatigue, excessive daytime somnolence (EDS), and depression can delay their recovery and potentially worsen outcomes. Psychostimulants, particularly modafinil (Provigil), have been shown to alleviate some of these symptoms in various patient populations, and as clinical trials are underway exploring this novel use of the drug, we present a case series of 3 patients in our institution's Thoracic Surgery Intensive Care Unit. Our 3 patients were chosen as a result of their fatigue, EDS, and/or depression, which prolonged their ICU stay and precluded them from participating in physical therapy, an integral component of the rehabilitative process. The patients were given 200 mg of modafinil each morning to increase patient wakefulness, encourage their participation, and enable a more restful sleep during the night. Although the drug was undoubtedly not the sole reason why our patients became more active, the temporal relationship between starting the drug and our patients' clinical improvement makes it likely that it contributed. Based on our observations with these patients, the known effects of modafinil, its safety profile, and the published experiences of others, we believe that modafinil has potential benefits when utilized in some critically ill patients and that the consequences of delayed patient recovery and a prolonged ICU stay may outweigh the risks of potential modafinil side effects.

Using an innovative multiple regression procedure in a cancer population (Part II): fever, depressive affect, and mobility problems clarify an influential symptom pair (pain-fatigue/weakness) and cluster (pain-fatigue/weakness-sleep problems)

Background

Most patients with advanced cancer experience symptom pairs or clusters among pain, fatigue, and insomnia. However, only combinations where symptoms are mutually influential hold potential for identifying patient subgroups at greater risk, and in some contexts, interventions with “cross-over” (multisymptom) effects. Improved methods to detect and interpret interactions among symptoms, signs, or biomarkers are needed to reveal these influential pairs and clusters. I recently created sequential residual centering (SRC) to reduce multicollinearity in moderated regression, which enhances sensitivity to detect these interactions.

Methods

I applied SRC to moderated regressions of single-item symptoms that interact to predict outcomes from 268 palliative radiation outpatients. I investigated: 1) the hypothesis that the interaction, pain × fatigue/weakness × sleep problems, predicts depressive affect only when fever presents, and 2) an exploratory analysis, when fever is absent, that the interaction, pain × fatigue/weakness × sleep problems × depressive affect, predicts mobility problems. In the fever context, three-way interactions (and derivative terms) of the four symptoms (pain, fatigue/weakness, fever, sleep problems) are tested individually and simultaneously; in the non-fever context, a single four-way interaction (and derivative terms) is tested.

Results

Fever interacts separately with fatigue/weakness and sleep problems; these comoderators each magnify the pain–depressive affect relationship along the upper or full range of pain values. In non-fever contexts, fatigue/weakness, sleep problems, and depressive affect comagnify the relationship between pain and mobility problems.

Conclusion

Different mechanisms contribute to the pain × fatigue/weakness × sleep problems interaction, but all depend on the presence of fever, a sign/biomarker/symptom of proinflammatory sickness behavior. In non-fever contexts, depressive affect is no longer an outcome representing malaise from the physical symptoms of sickness, but becomes a fourth symptom of the interaction. In outpatient subgroups at heightened risk, single interventions could potentially relieve multiple symptoms when fever accompanies sickness malaise and in non-fever contexts with mobility problems. SRC strengthens insights into symptom pairs/clusters.

The use of stimulant medications for non-core aspects of ADHD and in other disorders

Psychostimulants play a central role in the management of ADHD. Here we review the evidence pertaining to the use of methylphenidate, dexamphetamine and related amphetamine salts, the prodrug lisdexamfetamine and modafinil for the management of comorbid ADHD and non-ADHD indications. There is a growing consensus that stimulant medications are helpful at improving the emotional dysregulation and lability, and oppositional and conduct symptoms that are often associated with ADHD. There is some evidence that psychostimulants may improve outcomes in those with treatment resistant depression, reduce negative symptoms and improve cognitive performance in schizophrenia, and that methylphenidate may reduce binge eating in those with bulimia nervosa. In general medicine, whilst the evidence is at times contradictory, psychostimulants have been shown in some studies to be effective treatments for chronic fatigue and narcolepsy, and to improve outcomes post stroke, post head injury, in dementia and various cancers. It seems likely that these effects often result from a combination of, reduction in fatigue, improvements in concentration and cognitive functioning and a lifting of mood which may be a direct or indirect consequence of the medication. Further studies seem warranted and these should focus on efficacy, effectiveness and long term safety. This article is part of the Special Issue entitled 'CNS Stimulants'.

Modafinil reduces patient-reported tiredness after sedation/analgesia but does not improve patient psychomotor skills

BACKGROUND

Early recovery of patients following sedation/analgesia and anesthesia is important in ambulatory practice. The aim of this study was to assess whether modafinil, used for the treatment of narcolepsy, improves recovery following sedation/analgesia.

METHODS

Patients scheduled for extracorporeal shock wave lithotripsy were randomly assigned to one of four groups. Two groups received a combination of fentanyl/midazolam with either modafinil or placebo. The remaining groups received remifentanil/propofol with either modafinil or placebo. Modafinil 200 mg was administered to the treatment group patients 1 h before sedation/analgesia. Groups were compared using the digital symbol substitution test (DSST), trail making test (TMT), observer scale of sedation and analgesia (OAA/S) and Aldrete score. Verbal rating scale (VRS) scores for secondary outcome variables e.g. energy, tiredness and dizziness were also recorded before and after treatment.

RESULTS

Sixty-seven patients successfully completed the study. Groups received similar doses of sedation and analgesic drugs. No statistically significant difference was found for DSST between groups. No significant adverse effects occurred in relation to modafinil. No statistically significant difference between groups was identified for TMT, OAA/S and Aldrete scores. The mean VRS score for tiredness was lesser in the modafinil/fentanyl/midazolam group [1.3 (2.0)] compared with the placebo group [3.8 (2.5)], P=0.02. Such a difference was not found between the remifentanil/propofol groups [placebo 2.6 (2.2) vs. modafinil 3.1(2.7)], p>0.05. Dizziness was greater in the modafinil/remifentanil/propofol group 1.7 (2.0) vs. placebo 0.0 (0.5), p<0.05.

CONCLUSION

Modafinil reduces patient-reported tiredness after sedation/analgesia but does not improve recovery in terms of objective measures of patient psychomotor skills.

Modafinil for attentional and psychomotor dysfunction in advanced cancer: a double-blind, randomised, cross-over trial

Cognitive impairment seems to be highly prevalent in patients with advanced cancer. Modafinil, a novel vigilance and wake-promoting agent, may be an alternative treatment. We wanted to investigate this treatment on attentional and psychomotor dysfunction in cancer patients. 28 cancer patients with a tiredness score of 50 mm or more on a scale of 0 to 10 (0=no tiredness, 10=worst possible tiredness) and Karnofsky Performance Status 40-70 were included. All medications were kept stable during the trial despite short acting opioids for breakthrough pain. On day 1 the patients were randomly assigned to receive 200 mg Modafinil orally or placebo and on day 4 they crossed-over to the alternative treatment. Finger Tapping Test (FTT), Trail Making Test (TMT) and Edmonton Symptom Assessment System (ESAS) were evaluated before tablet intake and again 4, 5 hours after. FTT for the dominant hand as well as TMT were statistically significantly improved on modafinil (p-values=0.006 and 0.042, respectively). On ESAS, depression and drowsiness also improved statistically significantly (p-values=<0.001 and 0.038, respectively). Modafinil in a single dose regimen was significantly superior to placebo regarding two cognitive tests of psychomotor speed and attention. Furthermore subjective scores of depression and drowsiness were significantly improved by modafinil.

Management of expected and unexpected opioid-related side effects

Intolerable side effects contribute to poor outcomes among patients managed with opioids, and negotiating these side effects remains an important clinical challenge. Evidence-based approaches to minimizing the side-effect burden from opioids compiled from the literature, and including clinical practice recommendations, focus on (1) reducing the doses of systemic opioids, (2) managing the adverse symptoms of opioids, (3) integrating opioid rotation, and (4) changing the route of administration. These broad strategies, and specific recommendations for individual side effects of opioids, including those that often go unrecognized within the following organ systems: neurologic, cardiopulmonary, gastrointestinal, urologic, endocrinologic, dermatologic, and immunologic, are considered herein. In addition, specific patient populations, opioid metabolites, and clearance issues are considered. In particular, novel medications and better alternatives to preexisting treatments for specific opioid side effects, such as peripheral opioid antagonists, may ameliorate the management of patients taking long-term opioid therapies.

A randomized, placebo-controlled, crossover trial of cannabis cigarettes in neuropathic pain

The Food and Drug Administration (FDA), Substance Abuse and Mental Health Services Administration (SAMHSA), and the National Institute for Drug Abuse (NIDA) report that no sound scientific studies support the medicinal use of cannabis. Despite this lack of scientific validation, many patients routinely use "medical marijuana," and in many cases this use is for pain related to nerve injury. We conducted a double-blinded, placebo-controlled, crossover study evaluating the analgesic efficacy of smoking cannabis for neuropathic pain. Thirty-eight patients with central and peripheral neuropathic pain underwent a standardized procedure for smoking either high-dose (7%), low-dose (3.5%), or placebo cannabis. In addition to the primary outcome of pain intensity, secondary outcome measures included evoked pain using heat-pain threshold, sensitivity to light touch, psychoactive side effects, and neuropsychological performance. A mixed linear model demonstrated an analgesic response to smoking cannabis. No effect on evoked pain was seen. Psychoactive effects were minimal and well-tolerated, with some acute cognitive effects, particularly with memory, at higher doses.

PERSPECTIVE

This study adds to a growing body of evidence that cannabis may be effective at ameliorating neuropathic pain, and may be an alternative for patients who do not respond to, or cannot tolerate, other drugs. However, the use of marijuana as medicine may be limited by its method of administration (smoking) and modest acute cognitive effects, particularly at higher doses.

Evidence-informed management of chronic low back pain with opioid analgesics

The management of chronic low back pain (CLBP) has proven to be very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.

Fatigue in palliative care patients -- an EAPC approach

Fatigue is one of the most frequent symptoms in palliative care patients, reported in .80% of cancer patients and in up to 99% of patients following radio- or chemotherapy. Fatigue also plays a major role in palliative care for noncancer patients, with large percentages of patients with HIV, multiple sclerosis, chronic obstructive pulmonary disease or heart failure reporting fatigue. This paper presents the position of an expert working group of the European Association for Palliative Care (EAPC), evaluating the available evidence on diagnosis and treatment of fatigue in palliative care patients and providing the basis for future discussions. As the expert group feels that culture and language influence the approach to fatigue in different European countries, a focus was on cultural issues in the assessment and treatment of fatigue in palliative care. As a working definition, fatigue was defined as a subjective feeling of tiredness, weakness or lack of energy. Qualitative differences between fatigue in cancer patients and in healthy controls have been proposed, but these differences seem to be only an expression of the overwhelming intensity of cancer-related fatigue. The pathophysiology of fatigue in palliative care patients is not fully understood. For a systematic approach, primary fatigue, most probably related to high load of proinflammatory cytokines and secondary fatigue from concurrent syndromes and comorbidities may be differentiated. Fatigue is generally recognized as a multidimensional construct, with a physical and cognitive dimension acknowledged by all authors. As fatigue is an inherent word only in the English and French language, but not in other European languages, screening for fatigue should include questions on weakness as a paraphrase for the physical dimension and on tiredness as a paraphrase for the cognitive dimension. Treatment of fatigue should include causal interventions for secondary fatigue and symptomatic treatment with pharmacological and nonpharmacological interventions. Strong evidence has been accumulated that aerobic exercise will reduce fatigue levels in cancer survivors and patients receiving cancer treatment. In the final stage of life, fatigue may provide protection and shielding from suffering for the patient and thus treatment may be detrimental. Identification of the time point, where treatment of fatigue is no longer indicated is important to alleviate distress at the end of life.

Comparison of pramipexole and modafinil on arousal, autonomic, and endocrine functions in healthy volunteers

The noradrenergic locus coeruleus is a major wakefulness-promoting nucleus of the brain, which is also involved in the regulation of autonomic and endocrine functions. The activity of the locus coeruleus is believed to be tonically enhanced by a mesocoerulear dopaminergic pathway arising from the ventral tegmental area of the midbrain. Both modafinil, a wakefulness-promoting drug, and pramipexole, a D(2)/D(3)receptor agonist with sedative properties, may act on this pathway, with modafinil increasing and pramipexole decreasing locus coeruleus activity. The aim of this study was to compare the two drugs on alertness, autonomic and endocrine functions in healthy volunteers. Pramipexole (0.5mg), modafinil (200mg), and their combination were administered to 16 healthy males in a double-blind, placebo-controlled design. Methods included tests of alertness (pupillographic sleepiness test, critical flicker fusion frequency, visual analogue scales), autonomic functions (resting pupil diameter, light and darkness reflex responses, heart rate, blood pressure, salivation, core temperature), and endocrine functions (blood concentrations of prolactin, growth hormone, and thyroid stimulating hormone). Data were analysed by ANOVA. Pramipexole reduced alertness, caused pupil dilatation, increased heart rate, reduced prolactin and thyroid stimulating hormone, and increased growth hormone level. Modafinil caused small increases in blood pressure and core temperature, and reduced prolactin levels. The sedative effect of pramipexole and the autonomic effects of modafinil are consistent with altered activity in the mesocoerulear pathway; the pupil dilatation following pramipexole suggests reduced dopaminergic excitation of the Edinger-Westphal nucleus.

Behavioral effects of modafinil in marmoset monkeys

RATIONALE

Modafinil is increasingly used in sleep disturbances in general and in neurodegenerative diseases and is recently being used in healthy people for attention control. However, the application of modafinil is possibly not only restricted to alertness enhancing effects. More insight in this compound may lead to new applications. Not all behavioral aspects have been studied sufficiently; therefore, more detailed investigations on modafinil's positive and aversive behavioral effects are addressed in this paper.

OBJECTIVES

Determination of effects of modafinil in marmoset monkeys with observational methods and with behavioral tests measuring locomotor activity, hand-eye coordination, response to a threat situation and startle response.

MATERIALS AND METHODS

Two hours after oral administration of modafinil in doses of 50, 100, 150, and 225 mg/kg, animals were observed and tested in the behavioral test systems.

RESULTS

Locomotor activity was increased after 100 mg/kg modafinil in the Bungalow test and after 100, 150, and 225 mg/kg, as found in the movement parameters of the human threat test. Moreover, modafinil showed anxiolytic-like effects in the human threat test. No other side effects were observed, nor were the hand-eye coordination and startle response affected.

CONCLUSIONS

Besides psychostimulation, modafinil has no aversive effects in the doses used in the domains measured. The potential anxiolytic-like effects of modafinil may create new possibilities for the therapeutic use of modafinil.

Modafinil: new indications for wake promotion

In January 2004, the wake-promoting agent, modafinil, was approved in the US for the treatment of excessive sleepiness (ES) associated with obstructive sleep apnoea/hypopnoea syndrome (OSAHS) and shift-work sleep disorder (SWSD), representing an expansion of its labelling from the initial indication for ES associated with narcolepsy. A total of five randomised, placebo-controlled studies in these three disorders showed statistically significant benefits on various objective measures and subjective estimates of ES, including the Multiple Sleep Latency Test, Maintenance of Wakefulness Test, Epworth Sleepiness Scale and Karolinska Sleepiness Scale. Significant improvement was also seen in overall clinical condition (on the Clinical Global Impression of Change) and measures of sustained attention and reaction time (on the Psychomotor Vigilance Task). The clinical efficacy of modafinil, combined with improved safety over CNS stimulants, has made it the most prescribed medication for the treatment of ES associated with narcolepsy. Modafinil is the only medication approved for ES associated with OSAHS and SWSD (for OSAHS, it is indicated as an adjunct to standard treatments for the under-lying obstruction). Unlike many other medications used for ES, modafinil is not known to be abused. The most common adverse event reported in clinical studies was headaches; most were transient and mild-to-moderate in severity. Modafinil also has the potential for interactions with other drugs metabolised via cytochrome P450 enzyme pathways. Potential obstacles to the use of modafinil include an under-recognition of ES and its consequences. Increased education, both of the public and the medical community, should improve the recognition and therapy of ES.

Does modafinil activate the locus coeruleus in man? Comparison of modafinil and clonidine on arousal and autonomic functions in human volunteers

RATIONALE

Modafinil is a wakefulness-promoting drug which is likely to activate some wakefulness-promoting and/or inhibit sleep-promoting neurones in the brain. The locus coeruleus (LC) is a wakefulness-promoting noradrenergic nucleus whose activity can be "switched off" by the alpha2-adrenoceptor agonist clonidine, leading to sedative and sympatholytic effects.

OBJECTIVE

The aim of the study is to compare the effects of single doses of modafinil and clonidine on arousal and autonomic functions in human volunteers.

METHODS

Sixteen healthy male volunteers participated in four experimental sessions (modafinil 200 mg; clonidine 0.2 mg; modafinil 200 mg + clonidine 0.2 mg; placebo) at weekly intervals, according to a balanced double-blind protocol. Arousal [pupillary "fatigue waves" (PFW), critical flicker fusion frequency, self-ratings of alertness] and autonomic functions (pupil diameter, pupillary light and darkness reflex responses, blood pressure, heart rate, salivation) were recorded. Data were analyzed with ANOVA, with multiple comparisons.

RESULTS

Clonidine reduced subjective alertness, pupil diameter, the initial velocity and amplitude of the darkness reflex response, systolic and diastolic blood pressure and salivation, prolonged the recovery time of the light reflex response and increased PFW. Modafinil reduced PFW, increased pupil diameter and the initial velocity of the darkness reflex response and tended to reduce the effect of clonidine on pupil diameter and PFW. Modafinil had no effect on non-pupillary autonomic functions.

CONCLUSIONS

Clonidine exerted sympatholytic and sedative effects, whereas modafinil had sympathomimetic and some alerting effects. Modafinil may activate noradrenergic neurones in the LC involved in arousal and pupillary control, without affecting extracoerulear noradrenergic neurones involved in cardiovascular and salivary regulation.

The management of opioid-related sedation

There are many side effects of opioids used for cancer and non-cancer pain, which can limit their use and vastly undermine the quality of life for patients. Sedation is a frequent and serious side effect of opioid analgesics, sometimes reported as fatigue or tiredness from patients. There are a number of specific therapies to control or manage these adverse effects, making it feasible to dose opioids to adequate analgesia with tolerable side effects. The balance between effect and side effects is the goal of chronic opioid pharmacotherapy. In particular, sedation commonly can be problematic in a patient who is taking opioids, to the extent that one may want to discontinue the medication and suffer with the pain rather than experience debilitating fatigue or sedation. When sedation clinically becomes excessive, measures should be taken to make it possible to continue treatment with analgesics with acceptable sedation management. There are many techniques to oppose sedation including simple antidotes, such as rest, exercise, and timing of opioid medications, and more complex solutions, such as opioid rotation and the use of psychostimulants or other classes of medications to counteract sedation. The treatment of opioid-induced sedation can be very effective and should be part of a skill set that the clinician can easily employ to enhance the quality of life of patients.

Modafinil in sports: ethical considerations

Performance enhancing agents are prohibited in athletic competition so that only athletic skills can determine outcomes. Modafinil is a novel non-addicting psychostimulant approved for treatment of narcolepsy. Does its use, especially for medical indications, violate the Olympic Movement Anti-Doping Code? This is discussed with reference to a current high profile case.

Pharmacologic Treatment of Opioid-Induced Sedation in Chronic Pain

OBJECTIVE:

To review the literature for pharmacologic management of opioid-induced sedation (OIS) in patients with chronic pain.

DATA SOURCES:

A search of MEDLINE (1966–October 2004) for English-language literature and selected bibliographies was completed. Search terms included pain, opioid, sedation, psychostimulants, amphetamines, modafinil, and donepezil.

DATA SYNTHESIS:

Amphetamines and amphetamine-like agents, caffeine, donepezil, and modafinil have been evaluated for OIS. Available literature is limited by numbers of subjects, duration, and trial design; however, there is limited support for the use of methylphenidate, donepezil, and modafinil.

CONCLUSIONS:

Pharmacologic treatment of OIS should be utilized selectively, given the available literature. Methylphenidate, donepezil, and modafinil may be considered in appropriate patients.

Management of cancer pain

There are four basic approaches to cancer pain control: modify the source of pain, alter central perception of pain, modulate transmission of pain to the central nervous system, and block transmission of pain to the central nervous system. Systemic pharmacologic management aimed at the first three of these approaches is the cornerstone of the treatment of most cancer patients with moderate to severe pain. Optimal pharmacologic management of cancer pain requires selection of the appropriate analgesic drug; prescription of the appropriate dose; administration of the analgesic by the appropriate route; scheduling of the appropriate dosing interval; prevention of persistent pain and relief of breakthrough pain; aggressive titration of the dose of the analgesic; prevention, anticipation, and management of analgesic side effects; consideration of sequential trials of opioid analgesics; and use of appropriate co-analgesic drugs for specific pain syndromes. Most clinicians should be able to control most of the pain in most of their cancer patients. Collaboration with pain and hospice/palliative care experts should help the rest. No cancer patient should live or die with unrelieved pain.

Modafinil: Sedation (Drug Induced)

Off-Label Drug Uses

This Hospital Pharmacy feature is extracted from Off-Label DrugFacts, a quarterly publication available from Facts and Comparisons. Off-Label DrugFacts is a practitioner-oriented resource for information about specific FDA-unapproved drug uses. This new guide to the literature will enable the health care professional/clinician to quickly identify published studies on off-label uses and to determine if a specific use is rational in a patient care scenario. The most relevant data are provided in tabular form so that the reader can easily identify the scope of information available. A summary of the data—including background, study design, patient population, dosage information, therapy duration, results, safety, and therapeutic considerations—precedes each table of published studies. References direct the reader to the full literature for more comprehensive information prior to patient care decisions. Direct questions or comments on “Off-Label Drug Uses” to hospitalpharmacy@drugfacts.com .

Adjuvant Analgesics in Cancer Pain Management

Adjuvant analgesics are defined as drugs with a primary indication other than pain that have analgesic properties in some painful conditions. The group includes numerous drugs in diverse classes. Although the widespread use of these drugs as first-line agents in chronic nonmalignant pain syndromes suggests that the term "adjuvant" is a misnomer, they usually are combined with a less-than-satisfactory opioid regimen when administered for cancer pain. Some adjuvant analgesics are useful in several painful conditions and are described as multipurpose adjuvant analgesics (antidepressants, corticosteroids, alpha(2)-adrenergic agonists, neuroleptics), whereas others are specific for neuropathic pain (anticonvulsants, local anesthetics, N-methyl-D-aspartate receptor antagonists), bone pain (calcitonin, bisphosphonates, radiopharmaceuticals), musculoskeletal pain (muscle relaxants), or pain from bowel obstruction (octreotide, anticholinergics). This article reviews the evidence supporting the use of each class of adjuvant analgesic for the treatment of pain in cancer patients and provides a comprehensive outline of dosing recommendations, side effects, and drug interactions.