Apathy alters emotional arousal in chronic schizophrenia

Background

Within the heterogeneity of schizophrenia, apathy constitutes an independent cluster of negative symptoms associated with poor outcomes. Attempts to identify an emotional deficit in patients who have schizophrenia with negative symptoms have yielded mixed results, and studies that focus on the relationship between apathy and emotional disorders are lacking.

Methods

We set out to remedy this shortcoming using a validated battery of film excerpts to induce positive and negative emotions in patients with chronic schizophrenia with (n = 20) or without (n = 20) apathy, and in controls (n = 20) comparable for age, sex and socioeconomic status. We assessed emotions using an innovative but validated technique to evaluate tonic and phasic electrodermal activity and subjective feelings using a standardized visual analogue scale.

Results

Using a qualitative measure of apathy, we did not find a specific decrease in tonic activity during the induction of positive emotions. However, we did observe that patients with apathy showed reduced tonic activity independent of valence (i.e., for both positive and negative emotions) compared with controls and patients without apathy. Moreover, the quantitative measure of apathy (Apathy Evaluation Scale) was the only significant factor, explaining 24% of the variance in tonic activity during induction of positive emotions after controlling for confounding factors.

Limitations

Electrodermal activity was the only physiologic measure we acquired. We induced several emotions sequentially that might have overlapped with each other, but we added an emotional “washout” period and randomized the order of each film excerpt to limit this possibility.

Conclusion

Taken together, these results suggest that apathy in schizophrenia could impair tonic activity during positive emotions. Treatments aimed at enhancing positive emotions may help alleviate apathy in schizophrenia.

Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability

Athletes lose water and electrolytes as a consequence of thermoregulatory sweating during exercise and it is well known that the rate and composition of sweat loss can vary considerably within and among individuals. Many scientists and practitioners conduct sweat tests to determine sweat water and electrolyte losses of athletes during practice and competition. The information gleaned from sweat testing is often used to guide personalized fluid and electrolyte replacement recommendations for athletes; however, unstandardized methodological practices and challenging field conditions can produce inconsistent/inaccurate results. The primary objective of this paper is to provide a review of the literature regarding the effect of laboratory and field sweat-testing methodological variations on sweating rate (SR) and sweat composition (primarily sodium concentration [Na⁺]). The simplest and most accurate method to assess whole-body SR is via changes in body mass during exercise; however, potential confounding factors to consider are non-sweat sources of mass change and trapped sweat in clothing. In addition, variability in sweat [Na⁺] can result from differences in the type of collection system used (whole body or localized), the timing/duration of sweat collection, skin cleaning procedure, sample storage/handling, and analytical technique. Another aim of this paper is to briefly review factors that may impact intra/interindividual variability in SR and sweat [Na⁺] during exercise, including exercise intensity, environmental conditions, heat acclimation, aerobic capacity, body size/composition, wearing of protective equipment, sex, maturation, aging, diet, and/or hydration status. In summary, sweat testing can be a useful tool to estimate athletes’ SR and sweat Na⁺ loss to help guide fluid/electrolyte replacement strategies, provided that data are collected, analyzed, and interpreted appropriately.

Investigation on aetiological factors in patients with hyperhidrosis

BACKGROUND

Hyperhidrosis is a condition where the amount of sweat released to skin surface increases due to the over-active eccrine sweat glands. Hyperhidrosis causes considerable psychosocial distress in affected people. It affects the quality of life and leads to social anxiety disorders.

AIMS

No study has been conducted in our country to investigate the epidemiological, clinical, and laboratory data of patients with hyperhidrosis. In this study, we aimed to retrospectively investigate the clinical and demographic characteristics, causes of sweating and laboratory findings in patients treated for hyperhidrosis at our outpatient clinic and to compare these data with the literature data.

MATERIALS AND METHODS

A retrospective review was conducted on medical records of patients diagnosed with and treated for hyperhidrosis at outpatient clinic between 2014 and 2017. Adults aged over 18 years were included in study. Age and gender of patients, type and localization of sweating, duration of disease, age of onset of sweating, presence of stress, fever, joint pain and comorbidity, family history, medication use, and examination results were recorded.

RESULTS

Records of a total of 70 patients consisting of 30 men and 40 women with hyperhidrosis were examined. Overall mean age was 37.1 years. Mean age was 41 years in women and 32 years in men. Most frequent forms were palmoplantar and axillary hyperhidrosis for primary hyperhidrosis (primary HH), and head-neck and generalized hyperhidrosis for secondary hyperhidrosis (secondary HH). Most common comorbidities were diabetes mellitus, thyroid disease, non-specific joint and bone pain, cardiovascular disease, and neuropsychiatric disease. Cases with secondary HH had a history of drug use (antithyroid drugs, nonsteroidal anti-inflammatory drugs, antidiabetic agents, antidepressants, and antihypertensives).

CONCLUSION

This is the first study that investigated the characteristics of patients with primary and secondary HH in our country. These characteristics can help determine the cause and apply treatment for hyperhidrosis by an appropriate examination and approach.

Meta-analysis: Risk of hyperhidrosis with second-generation antidepressants

BACKGROUND

Our goal was to quantify the risk of hyperhidrosis associated with commonly used antidepressant agents and examine the impact of medication class, pharmacodynamics, and dose on risk of hyperhidrosis.

METHODS

We conducted a PubMed search to identify all double-blind, randomized, placebo-controlled trials examining the efficacy of second-generation antidepressant medications in the treatment of adults with a depressive disorder, anxiety disorders, or obsessive-compulsive disorder. We used a random-effects meta-analysis to examine the pooled risk ratio of hyperhidrosis reported as a side effect in adults treated with second-generation antidepressants compared to placebo. We used stratified subgroup analysis and metaregression to examine the effects of medication type, class, dosage, indication, and receptor affinity profile on the measured risk of hyperhidrosis.

RESULTS

We identified 76 trials involving 28,544 subjects. There was no significant difference in the risk of hyperhidrosis between serotonin-norepinephrine reuptake inhibitors (SNRI) [risk ratio (RR) = 3.17, 95% CI: 2.63-3.82] and selective serotonin reuptake inhibitors (SSRI) (RR = 2.93, 95% CI: 2.46-3.47) medications compared to placebo. All antidepressant medications were associated with a significantly increased risk of hyperhidrosis except fluvoxamine (RR = 0.56, 95% CI: 0.12-2.53), bupropion (RR = 1.23, 95% CI: 0.57-2.67), and vortioxetine (RR = 1.35, 95% CI: 0.79-2.33). The dose of SSRI/SNRI medications was not significantly associated with the risk of hyperhidrosis. Increased risk of hyperhidrosis was associated with increased affinity of SSRI/SNRI medications to the dopamine transporter.

CONCLUSION

Risk of hyperhidrosis was significantly increased with most antidepressant medications but was associated with dopamine transporter affinity.

The Safety, Tolerability and Risks Associated with the Use of Newer Generation Antidepressant Drugs: A Critical Review of the Literature

Newer generation antidepressant drugs (ADs) are widely used as the first line of treatment for major depressive disorders and are considered to be safer than tricyclic agents. In this critical review, we evaluated the literature on adverse events, tolerability and safety of selective serotonin reuptake inhibitors, serotonin noradrenaline reuptake inhibitors, bupropion, mirtazapine, trazodone, agomelatine, vilazodone, levomilnacipran and vortioxetine. Several side effects are transient and may disappear after a few weeks following treatment initiation, but potentially serious adverse events may persist or ensue later. They encompass gastrointestinal symptoms (nausea, diarrhea, gastric bleeding, dyspepsia), hepatotoxicity, weight gain and metabolic abnormalities, cardiovascular disturbances (heart rate, QT interval prolongation, hypertension, orthostatic hypotension), genitourinary symptoms (urinary retention, incontinence), sexual dysfunction, hyponatremia, osteoporosis and risk of fractures, bleeding, central nervous system disturbances (lowering of seizure threshold, extrapyramidal side effects, cognitive disturbances), sweating, sleep disturbances, affective disturbances (apathy, switches, paradoxical effects), ophthalmic manifestations (glaucoma, cataract) and hyperprolactinemia. At times, such adverse events may persist after drug discontinuation, yielding iatrogenic comorbidity. Other areas of concern involve suicidality, safety in overdose, discontinuation syndromes, risks during pregnancy and breast feeding, as well as risk of malignancies. Thus, the rational selection of ADs should consider the potential benefits and risks, likelihood of responsiveness to the treatment option and vulnerability to adverse events. The findings of this review should alert the physician to carefully review the appropriateness of AD prescription on an individual basis and to consider alternative treatments if available.

Current and Emerging Medical Therapies for Primary Hyperhidrosis

Hyperhidrosis is defined as the production of sweat beyond what is physiologically necessary to maintain thermal homeostasis. This disease state may (and typically does) have a significant impact on the patient’s quality of life. Medications including antiperspirants, anticholinergics, and botulinum toxin have been shown to be effective in the management of hyperhidrosis. Several medical device technologies have also proven to be effective. This review article will explore the current and emerging pharmacological and medical device treatments for hyperhidrosis and provide a framework for treating patients who suffer with primary forms of hyperhidrosis.

Hospitalizations from Hypertensive Diseases, Diabetes, and Arrhythmia in Relation to Low and High Temperatures: Population-Based Study

Little is known about the extent to which ambient temperatures contribute to the burden of hospitalizations from hypertensive diseases, diabetes, and arrhythmia. To fill this knowledge gap, we conducted a time-series study comprising entire population of Ontario, Canada during 1996–2013. A distributed lag non-linear model was developed to estimate the cumulative effect of temperatures over a 21-day lag period. We computed the burden of hospitalizations attributable to cold and heat. Furthermore, we separated the burden into components related to mild and extreme temperatures. Compared to the temperature with minimum risk of morbidity, cold temperatures (1^st percentile) were associated with a 37% (95% confidence interval: 5%, 78%) increase in hypertension-related hospitalizations whereas no significant association with hot temperatures (99^th percentile) was observed. Cold and hot temperatures were also associated with a 12% (1%, 24%) and a 30% (6%, 58%) increase in diabetes-related hospitalizations, respectively. Arrhythmia was not linked to temperatures. These estimates translate into ~10% of hypertension-related hospitalizations attributable to total cold, and ~9% from mild cold. Similarly, ~11% of diabetes-related hospitalizations were due to total heat, virtually all of which were from mild heat. In conclusion, ambient temperatures, especially in moderate ranges, contribute to excess hospitalizations from hypertension and diabetes.

Palmar hyperhidrosis treated by noninvasive ultrasound stellate ganglion block

Focal palmar hyperhidrosis is a common and often debilitating eccrine sweat gland disorder with negative impact on quality of life and self-esteem. For treatment of recalcitrant cases, a stellate ganglion block is a nonsurgical alternative. Although this method has only a temporary effect, surgical risks can be avoided. The usual way to perform the block is by ultrasound-guided injection of local anesthetics. Here we describe the use of therapeutic ultrasound at 0.8 MHz for stellate ganglion block. Ultrasound was applied for 1 min unilaterally every other day for 6 days. The efficacy was monitored by video capillaroscopy and Minor's iodine starch test. Treatment was well tolerated and no adverse effects were noted. Sweating was stopped and capillary blood flow increased. The effect lasted for several weeks.

Body temperature regulation in diabetes

The effects of type 1 and type 2 diabetes on the body's physiological response to thermal stress is a relatively new topic in research. Diabetes tends to place individuals at greater risk for heat-related illness during heat waves and physical activity due to an impaired capacity to dissipate heat. Specifically, individuals with diabetes have been reported to have lower skin blood flow and sweating responses during heat exposure and this can have important consequences on cardiovascular regulation and glycemic control. Those who are particularly vulnerable include individuals with poor glycemic control and who are affected by diabetes-related complications. On the other hand, good glycemic control and maintenance of aerobic fitness can often delay the diabetes-related complications and possibly the impairments in heat loss. Despite this, it is alarming to note the lack of information regarding diabetes and heat stress given the vulnerability of this population. In contrast, few studies have examined the effects of cold exposure on individuals with diabetes with the exception of its therapeutic potential, particularly for type 2 diabetes. This review summarizes the current state of knowledge regarding the impact of diabetes on heat and cold exposure with respect to the core temperature regulation, cardiovascular adjustments and glycemic control while also considering the beneficial effects of maintaining aerobic fitness.

Human cardiovascular responses to passive heat stress

Heat stress increases human morbidity and mortality compared to normothermic conditions. Many occupations, disease states, as well as stages of life are especially vulnerable to the stress imposed on the cardiovascular system during exposure to hot ambient conditions. This review focuses on the cardiovascular responses to heat stress that are necessary for heat dissipation. To accomplish this regulatory feat requires complex autonomic nervous system control of the heart and various vascular beds. For example, during heat stress cardiac output increases up to twofold, by increases in heart rate and an active maintenance of stroke volume via increases in inotropy in the presence of decreases in cardiac preload. Baroreflexes retain the ability to regulate blood pressure in many, but not all, heat stress conditions. Central hypovolemia is another cardiovascular challenge brought about by heat stress, which if added to a subsequent central volumetric stress, such as hemorrhage, can be problematic and potentially dangerous, as syncope and cardiovascular collapse may ensue. These combined stresses can compromise blood flow and oxygenation to important tissues such as the brain. It is notable that this compromised condition can occur at cardiac outputs that are adequate during normothermic conditions but are inadequate in heat because of the increased systemic vascular conductance associated with cutaneous vasodilation. Understanding the mechanisms within this complex regulatory system will allow for the development of treatment recommendations and countermeasures to reduce risks during the ever-increasing frequency of severe heat events that are predicted to occur.

Selective Serotonin Reuptake Inhibitors and Night Sweats in a Primary Care Population

Objective

Several small published case reports have suggested that selective serotonin reuptake inhibitors (SSRIs) can cause night sweats. The purpose of this study was to investigate this possibility further and to explore possible associations between night sweats and other commonly prescribed medications.

Design

Cross-sectional, secondary data analysis.

Setting

Data were obtained during the Oklahoma Longitudinal Assessment of the Health Outcomes of Mature Adults, a longitudinal cohort study carried out in the Oklahoma Physicians Resource/Research Network.

Participants

413 adult primary care patients aged 65–94 years.

Interventions

Current regular use of one of 35 classes of medication.

Main Outcome Measures

At least moderate night sweats during the prior month.

Results

A total of 38 (9.2 %) reported night sweats. Age, gender, body mass index, and total number of medications taken regularly were not associated with night sweats. After adjusting for age and gender, SSRIs (odds ratio [OR] 3.01; 95 % confidence interval [CI] 1.26–7.19), angiotensin receptor blockers (ARBs) (OR 3.44; 95 % CI 1.36–8.69), and thyroid hormone supplements (OR 2.53; 95 % CI 1.24–5.15) were the only classes of medications associated with night sweats.

Conclusions

Use of SSRIs may well be associated with night sweats in older patients. Associations found between night sweats and ARBs and thyroid supplements warrant further study.

Adverse reactions of Methylphenidate in children with attention deficit-hyperactivity disorder: Report from a referral center

Objective:

The aim of the current study was to determine various aspects of methylphenidate adverse reactions in children with attention deficit-hyperactivity disorder (ADHD) in Iran.

Methods:

During the 6 months period, all children under methylphenidate treatment alone or along with other agents attending a university-affiliated psychology clinic were screened regarding all subjective and objective adverse drug reactions (ADRs) of methylphenidate. Causality and seriousness of detected ADRs were assessed by relevant World Health Organization definitions. The Schumock and Thornton questionnaire was used to determine preventability of ADRs.

Findings:

Seventy-one patients including 25 girls and 46 boys with ADHD under methylphenidate treatment were enrolled within the study period. All (100%) ADHD children under methylphenidate treatment developed at least one ADR. Anorexia (74.3%), irritability (57.1%), and insomnia (47.2%) were the most frequent methylphenidate-related adverse reactions. Except for one, all other detected ADRs were determined to be mild. In addition, no ADR was considered to be preventable and serious.

Conclusion:

Our data suggested that although methylphenidate related adverse reactions were common in children with ADHD, but they were mainly mild and nonserious.

Analysis of oxybutynin treatment for hyperhidrosis in patients aged over 40 years

Objective:

Our aim was to analyze the effectiveness of oxybutynin for hyperhidrosis treatment in patients over 40 years.

Methods:

Eighty-seven patients aged over 40 years were divided into two groups. One group consisted of 48 (55.2%) patients aged between 40 and 49 years, and another was composed of 39 (44.8%) patients aged over 50 years (50 to 74 years). A comparative analysis of Quality of Life and level of hyperhidrosis between the groups was carried out 6 weeks after a protocol treatment with oxybutynin. A validated clinical questionnaire was used for evaluation.

Results:

In the younger age group, 75% of patients referred a “partial” or “great” improvement in level of hyperhidrosis after treatment. This number was particularly impressive in patients over 50 years, in which 87.2% of the cases demonstrated similar levels of improvement. Over 77% of patients in both groups demonstrated improvement in Quality of Life. Excellent outcomes were observed in older patients, in which 87.1% of patients presented “slightly better” (41%) or “much better” (46.1%) improvement.

Conclusion:

Patients aged over 40 years with hyperhidrosis presented excellent results after oxybutynin treatment. These outcomes were particularly impressive in the age group over 50 years, in which most patients had significant improvement in Quality of Life and in level of hyperhidrosis.

Pharmacokinetic and pharmacodynamic interactions between antiepileptics and antidepressants

INTRODUCTION

Antiepileptic-antidepressant combinations are frequently used by clinicians; their pharmacokinetic (PK) and pharmacodynamic (PD) drug interactions (DIs) have not been well studied but are frequently likely to be clinically relevant.

AREAS COVERED

This article provides a comprehensive review of PK DIs between antiepileptics and antidepressants. In the absence of PD DI studies, PD information on pharmacological mechanisms and studies on efficacy and safety of individual drugs are reviewed.

EXPERT OPINION

The clinical relevance of the inductive properties of carbamazepine, phenytoin, phenobarbital and primidone and the inhibitory properties of valproic acid and some antidepressants are well understood; correction factors are provided if appropriate DI studies have been completed. More PK studies are needed for: i) antiepileptics with potent inductive effects for all recently approved antidepressants; ii) high doses of mild CYP3A4 inducers, such as clobazam, eslicarbazepine, oxcarbazepine, rufinamide and topiramate for reboxetine and vilazodone; iii) valproate as a possible inhibitor, mild inducer or both a mild inducer and competitive inhibitor of some antidepressants; and iv) inhibitory effects of long-term fluoxetine use on clobazam, lacosamide, phenobarbital, primidone, carbamazepine, felbamate, tiagabine and zonisamide. Possible synergistic or additive beneficial PD DIs in generalized anxiety disorder, chronic pain, migraine prophylaxis, weight control and menopausal symptoms need study.

Oxybutynin reduces sweating in depressed patients treated with sertraline: a double-blind, placebo-controlled, clinical study

BACKGROUND

Selective serotonin reuptake inhibitors are primarily used in the pharmacological treatment of patients experiencing a major depressive disorder. However, one of the common unwanted effects is excessive sweating or hyperhidrosis. Oxybutynin is an anticholinergic medication which reduces sweating. The aim of this double-blind study was to examine the effect of administration of oxybutynin on subjective sweating in patients treated with sertraline.

METHODS

A total of 140 patients experiencing a major depressive disorder (mean age 37.69 ± 10.44 years, 86 females [61.4%]) treated with sertraline (mean dose 83 mg/day) were consecutively enrolled in the study, and all reported excessive sweating as a side effect. Thereafter, the patients were randomly assigned to either an oxybutynin 5 mg/day group or to a placebo group. At the beginning and end of the 2-week trial, the patients completed questionnaires related to sweating and medication-related side effects.

RESULTS

Over time, subjective sweating reduced significantly in the treatment group as compared with the control group. Oxybutynin-induced side effects were uncommon. Relative to male patients, female patients reported less subjective sweating.

CONCLUSION

Administration of oxybutynin successfully reduced excessive sweating in patients experiencing a major depressive disorder and treated with sertraline. However, possible gender effects should be taken into account.

Treatment options for hyperhidrosis

Hyperhidrosis is a disorder of excessive sweating beyond what is expected for thermoregulatory needs and environmental conditions. Primary hyperhidrosis has an estimated prevalence of nearly 3% and is associated with significant medical and psychosocial consequences. Most cases of hyperhidrosis involve areas of high eccrine density, particularly the axillae, palms, and soles, and less often the craniofacial area. Multiple therapies are available for the treatment of hyperhidrosis. Options include topical medications (most commonly aluminum chloride), iontophoresis, botulinum toxin injections, systemic medications (including glycopyrrolate and clonidine), and surgery (most commonly endoscopic thoracic sympathectomy [ETS]). The purpose of this article is to comprehensively review the literature on the subject, with a focus on new and emerging treatment options. Updated therapeutic algorithms are proposed for each commonly affected anatomic site, with practical procedural guidelines. For axillary and palmoplantar hyperhidrosis, topical treatment is recommended as first-line treatment. For axillary hyperhidrosis, botulinum toxin injections are recommended as second-line treatment, oral medications as third-line treatment, local surgery as fourth-line treatment, and ETS as fifth-line treatment. For palmar and plantar hyperhidrosis, we consider a trial of oral medications (glycopyrrolate 1-2 mg once or twice daily preferred to clonidine 0.1 mg twice daily) as second-line therapy due to the low cost, convenience, and emerging literature supporting their excellent safety and reasonable efficacy. Iontophoresis is considered third-line therapy for palmoplantar hyperhidrosis; efficacy is high although so are the initial levels of cost and inconvenience. Botulinum toxin injections are considered fourth-line treatment for palmoplantar hyperhidrosis; efficacy is high though the treatment remains expensive, must be repeated every 3-6 months, and is associated with pain and/or anesthesia-related complications. ETS is a fifth-line option for palmar hyperhidrosis but is not recommended for plantar hyperhidrosis due to anatomic risks. For craniofacial hyperhidrosis, oral medications (either glycopyrrolate or clonidine) are considered first-line therapy. Topical medications or botulinum toxin injections may be useful in some cases and ETS is an option for severe craniofacial hyperhidrosis.

Clinical differentiation of primary from secondary hyperhidrosis

BACKGROUND

Hyperhidrosis (HH) is excessive sweating that may be primary (idiopathic) or secondary to medication or disease. Clinical features supporting primary or secondary etiology have not been well documented.

OBJECTIVE

To identify clinical and demographic features predictive of a diagnosis of primary versus secondary HH.

METHODS

A retrospective chart review was conducted over a 13-year period (1993-2005) of all patients (children and adults) seen at a university-based outpatient dermatology department with an International Classification of Diseases, 9th revision diagnosis code for HH (N = 415).

RESULTS

Three hundred eighty-seven patients (93.3%) had primary HH (PHH); 28 patients (6.7%) had secondary HH (SHH). SHH patients were older (39.0 ± 18.6 years vs 27.3 ± 12.3 years) with more frequent onset at age older than 25 years (55% for SHH vs12.1% for PHH; odds ratio [OR] 8.7; 95% confidence interval [CI] 3.5-21.4; P < .00001 for each). SHH was more often unilateral/asymmetric (OR: 51; 95% CI: 12.6-208), generalized (vs focal; OR: 18; 95% CI: 7.3-47.6), and present nocturnally (OR: 23.2; 95% CI: 4.3-126; P < .00001 for each). Of SHH cases, endocrine disease accounted for 57% (including diabetes mellitus [11], hyperthyroidism [4], and hyperpituitarism [1]). Neurologic disease accounted for 32% (including peripheral nerve injury [3], Parkinson's disease [2], reflex sympathetic dystrophy [2], spinal injury [1] and Arnold-Chiari malformation [1]). Malignancy (pheochromocytoma), respiratory disease, and psychiatric disease were each represented once. Compared to other secondary causes, asymmetric HH favored neurologic disease (OR: 63; 95% CI: 4.9-810); P = .0002).

LIMITATIONS

Results were obtained from a single, university-based population.

CONCLUSIONS

On the basis of these data, the diagnostic criteria for PHH were assessed statistically. Criteria include: excessive sweating of 6 months or more in duration, with 4 or more of the following: primarily involving eccrine-dense (axillae/palms/soles/craniofacial) sites; bilateral and symmetric; absent nocturnally; episodes at least weekly; onset at 25 years of age or younger; positive family history; and impairing daily activities. These criteria discriminate well between PHH and SHH (sensitivity: 0.99; specificity: 0.82; positive predictive value: 0.99; negative predictive value: 0.852) and may facilitate optimal clinical management.

Hyperhidrosis in association with efavirenz

Hyperhidrosis may be an adverse drug event (ADE) induced by the effect on any of the components of human thermoregulation. Some of our efavirenz (EFV)-treated patients have reported excessive nocturnal sweating that resolved after dose reduction. A representative clinical case of a male patient being treated with a night-time 600-mg dose of EFV who reported severe nocturnal sweating is reported here. His EFV plasma concentrations were always above normal and he was homozygous for a deficient function-allele of CYP2D6; for this reason, his EFV dose was reduced to 400mg=d. Simultaneous with this reduction, the patient described a progressive decrease in nocturnal sweating until its complete disappearance 15-20 days after this new drug dosage. The mechanism explaining sweating could be similar to the one suggested for hyperhidrosis related to serotonin uptake inhibitors, because this hyperhidrosis is episodic, nocturnal, and dose dependent. Hyperhidrosis could correspond to a dose-dependent ADE induced by EFV, therefore, a reduction of EFV from 600 to 400mg/d seems to control it. EFV crosses the hematoencephalic barrier and reaches a mean concentration in the cerebroespinal fluid equivalent to 0.69% of the plasma concentration. The ability of EFV to accessing the central nervous system (CNS) could explain an effect on thermoregulation. Hyperhydrosis is not easily discovered through a routine anamnesis because it is not noted on the EFV package insert, so its incidence may be higher than expected. Additionally, hyperhidrosis may be an indicator of elevated EFV plasma concentrations and hence may be controlled through a reduction of dose.