Efficacy of dupilumab in chronic prurigo and chronic idiopathic pruritus: a systematic review of current evidence and analysis of response predictors.

Dupilumab has demonstrated a great reduction in chronic pruritus that is the hallmark of atopic dermatitis (AD). Underscoring relevant pathogenesis similarities emerging from AD, chronic idiopathic pruritus (CIP) and chronic prurigo (CP), several authors suggested the beneficial role of dupilumab in these conditions. The evidence on this subject is limited with no precise data available. In this study, we carried out a systematic literature review in order to evaluate the efficacy of dupilumab on both pruritus and skin manifestations in the two largest retrospective cohorts of patients with CP and CIP and tried to identify potential response predictors. Electronic searches were conducted on 4 databases. Our primary outcome was the improvement in pruritus measured by a reduction in the patient's reported numerical rating scale of itch (NRSI) by >4. Secondary outcomes included the proportion of patients with a complete response at the end of treatment, reduction in the number of lesions by the Investigator Global Assessment (IGA), improvement in numerical rating scale of sleep (NRSS), improvement in quality of life measured by the Dermatology Life Quality Index (DLQI), time until patient perceived any improvement (Time-First) and time until the patient-reported absence of pruritus (Time-Final). Descriptive statistics were calculated for each demographic and clinical variable. Univariate logistic regression analyses were conducted to explore the association between response to dupilumab and potential predictive factors. We included 25 articles in the analysis, counting a total of 153 patients. Based on CP patients' cohort (n = 132), the mean NRSI at baseline was 8.79 ± 0.86 and the NRSI final was 2.32 ± 1.27. The mean time to first improvement was 5.18 ± 3.13 weeks, while the time to complete improvement of pruritus (Time-final) was 13.6 ± 12.0 weeks. Ninety patients out of 109 (83%) noticed an improvement in pruritus before 4 weeks of dupilumab therapy. At the end of treatment, 18 patients out of 126 (14%) had a complete remission of pruritus and 110 patients out of 123 (89%) had a reduction of NRSI >4. The reduction in NRSI was significantly greater in patients improving before 4 weeks of treatment (6.57 ± 1.71) compared with patients improving in more than 4 weeks (5.49 ± 1.39, P < 0.001). Patients with history of AD and those who have been previously treated with cyclosporine or methotrexate had a significantly lower reduction in NRSI (e.g. 6.05 ± 1.34 vs. 7.08 ± 1.90, P < 0.01 for nonassociated AD patients). Based on CIP patient's cohort (n = 21), the mean NRSI at baseline was 8.33 ± 0.80 and the NRSI final was 0.95 ± 0.59. The mean time to first improvement was 2 ± 0 weeks, while the time to complete improvement (Time-final) was 14.6 ± 10 weeks. At the end of treatment, 3 patients out of 21 (14%) had a complete remission of pruritus and 100% of patients had a reduction of NRSI >4. No serious treatment-emergent adverse events were reported. The most common adverse event was mild conjunctivitis (13 cases). We highlight the importance of one early sign of improvement as a predictor of the future response to dupilumab: the improvement before 4 weeks of treatment that leads significantly to a greater final reduction in NRSI. Furthermore, patients with the presence or history of atopy appear to be less responsive to dupilumab than nonatopic patients and develop more side effects, in particular conjunctivitis.

[Cutaneous metastases on the extremities]. / Métastases cutanées des extrémités.

BACKGROUND: Cutaneous metastases (CM) on the extremities are rare complication of cancer with poor prognosis. In general, lesions simulate an infection. Herein, we report two new cases with atypical presentation. PATIENTS AND METHODS: Case no 1: a 71-year-old man consulted for suspicion of left hand pyogenic granuloma present for 3 months. His history revealed two treated squamous-cell carcinomas (tongue and lung). On physical examination, he presented three budding and foul-smelling lesions on his left hand. Histopathology showed metastasis of squamous-cell carcinoma. Radiographic examination revealed spread of pulmonary nodules with suspicion of metastasis. Case no 2: a 68-year-old man was hospitalized for indurated edema of the right leg present for several months. Six months earlier, he had undergone surgery for left pulmonary adenocarcinoma without metastasis. Physical examination revealed an indurated edema on the right foot. Histopathology showed metastasis from adenocarcinoma. A scan revealed several osteolytic lesions in the right foot as well as lymphadenopathy. DISCUSSION: Herein, we report two original cases of CM of the extremities diagnosed as tumor progression. This is a rare complication of variable clinical presentation and impacts both cancer management and prognosis. It is important to consider the diagnosis when distal cutaneous lesions persist, particularly where there is a history of cancer.

Combined effect of divergent selection for breast muscle ultimate pH and dietary amino acids on chicken performance, physical activity and meat quality.

Responses to changes in dietary Lys and other essential amino acid (AA) concentrations were evaluated in 480 male and female broilers originating from two lines divergently selected for high (pHu+) or low (pHu-) ultimate pH (pHu) of breast muscle. The two genetic lines were fed with two grower isoenergetic diets differing in both true digestible Lys (control=10.2 g/kg and experimental=7.0 g/kg) and amounts of other essential AA calculated in relation to Lys, which were sufficient for the control diet or in excess for the experimental diet. There were six repetitions per treatment. Birds were weighed individually at days 0, 21, 28 and 43. Feed consumption was recorded per pen and feed conversion was calculated over the growing period. The physical activity and walking ability of broilers were recorded during the whole rearing period. Breast and leg yield, and abdominal fat percentage were measured at 43 days of age, as were pHu, color, drip and cooking loss, Warner-Bratzler shear force, and curing-cooking yield of the breast Pectoralis major and pHu of the thigh Sartorius muscle. Divergent selection greatly affected most breast meat quality traits without significantly changing growth rate or feed efficiency. When subjected to a variation in dietary intake of AA, birds from the two genotypes responded in a similar way in terms of animal's growth, feed efficiency, body composition and meat quality traits. Although line and diet did not affect physical or feeding activities of the broilers, a significant effect of line-by-diet interaction was observed on gait score. Contrary to the pHu- birds, the walking ability of pHu+ birds was impaired when fed the control diet that favored growth and breast muscle development and limited storage of carbohydrate in muscle.

5-HT2C receptors in psychiatric disorders: A review.

5-HT2Rs have a different genomic organization from other 5-HT2Rs. 5HT2CR undergoes post-transcriptional pre-mRNA editing generating diversity among RNA transcripts. Selective post-transcriptional editing could be involved in the pathophysiology of psychiatric disorders through impairment in G-protein interactions. Moreover, it may influence the therapeutic response to agents such as atypical antipsychotic drugs. Additionally, 5-HT2CR exhibits alternative splicing. Central serotonergic and dopaminergic systems interact to modulate normal and abnormal behaviors. Thus, 5HT2CR plays a crucial role in psychiatric disorders. 5HT2CR could be a relevant pharmacological target in the treatment of neuropsychiatric disorders. The development of drugs that specifically target 5-HT2C receptors will allow for better understanding of their involvement in the pathophysiology of psychiatric disorders including schizophrenia, anxiety, and depression. Among therapeutic means currently available, most drugs used to treat highly morbid psychiatric diseases interact at least partly with 5-HT2CRs. Pharmacologically, 5HT2CRs, have the ability to generate differentially distinct response signal transduction pathways depending on the type of 5HT2CR agonist. Although this receptor property has been clearly demonstrated, in vitro, the eventual beneficial impact of this property opens new perspectives in the development of agonists that could activate signal transduction pathways leading to better therapeutic efficiency with fewer adverse effects.

Sex- and tissue-specific expression of "similar to nothepsin" and cathepsin D in relation to egg yolk formation in Gallus gallus.

Egg yolk constitutes the main storage compartment of the avian egg and the first nutritional source that supports embryonic growth. Most egg yolk components are synthesized by the liver of laying hens at sexual maturity and are secreted into the blood to be further transferred into the ovarian oocyte (yolky follicle) by receptor-mediated endocytosis. Egg yolk proteins are secreted as precursors and must undergo proteolytic processing to be bioactive. It is assumed that chicken cathepsin D, an aspartic protease, is a key enzyme in this process. Very recently, a novel aspartic protease, namely "similar to nothepsin," has been identified in the egg yolk. Previous experiments conducted in Antarctic fish have shown that the expression of nothepsin is tissue- and sex-specific. To gain insight into the specificities of expression of both cathepsin D and "similar to nothepsin" in Gallus gallus, we compared their distribution in various tissues, in male and females. Cathepsin D is ubiquitously expressed in all tissues examined, including liver of both male and female adults, and its expression is stable during sexual maturation. In contrast, "similar to nothepsin" expression is unique to the liver of adult females and is sex steroid-dependent as it increases gradually in the liver of hens during sexual maturation. The sexual dimorphic expression of the "similar to nothepsin" gene suggests that the activity of this protein is regulated by the steroid environment of laying hens and is specifically adapted for inclusion in the yolk. Further studies are needed to assess whether "similar to nothepsin" assists cathepsin D in the proteolytic processing of egg yolk proteins during follicular growth.

[The problems with the use of benzodiazepines in elderly patients]. / Les problèmes posés par l'utilisation des benzodiazépines chez le patient âgé

Benzodiazepines (BZD) are widely used to treat anxiety and insomnia in elderly patients. The interest of this prescription is discussed in this article. The discussion is based on the pharmacological properties and adverse effects of BZDs in the elderly. The conclusions are that BZDs should be rarely prescribed in this population; many patients treated by BZDs should be withdrawn and therapeutic strategies, other than BZDs, should be considered to treat anxiety and insomnia in these patients. Problems posed by BZD in the aged patient are both of a pharmacodynamic and pharmacokinetic order. In comparison to young adult users, BZD users among the aged are essentially women; the latter take these medications during important periods in their lives and often have a strong comorbidity, such as cardiovascular or rhumatological problems or even psychiatric problems, such as depression or panic disorders. Aged patients who take BZD at high doses can also consume other drugs, such as alcohol, and often have a psychiatric history. Some important side effects are associated with the use of BZD; essentially concerning falls, and it has been noticed for some years that problems posed by aged car drivers can be enhanced by BZD. It is difficult to know if continual users of BZD really have an advantage over other users. However, instruments, such as an indicator in the form of an algorithm, have been developed to identify the appropriateness of prescribing BZD to elderly patients. It is obvious that it is essential, whenever possible, to have a recourse strategy for cessation, and as much as possible to use BZD with a short half-life that are not oxidised, i.e. essentially BZD that are not metabolised in the strictest sense of the term, such as lorazepam or temazepam. Daily doses must be extremely limited and duration of use should not exceed two or three months in young patients.

Factors triggering abolishment of benzodiazepines effects in the Four-Plate Test--retest in mice.

Abolishment of anxiolytic-like effects of diazepam occurs during re-exposure to some animal tests of anxiety. We investigated the loss of anxiolytic-like effects of diazepam during Trial 2 on previously undrugged mice, namely one-trial tolerance (OTT). Swiss mice were subjected to 1) Four-Plate Test (FPT) without punishments in Trial 1 or 2) FPT without punishments in both Trials or 3) FPT with spatial modifications in Trial 1 or 4) Elevated Plus Maze (EPM), then 24 h later to FPT, with saline, diazepam (1 mg/kg) or DOI (1 mg/kg). Removing punishments in Trial 1 does not counteract the effect reduction of diazepam in Trial 2, but spatial modifications of the aversive environment. Previous exposure to EPM does not trigger a loss of efficacy of diazepam in FPT. Electric punishments do not trigger OTT to benzodiazepines; whilst knowledge of the environment seems to be responsible for this phenomenon. FPT may be useful to study OTT because punishments potentate OTT in this model of anxiety.

Dopamine dysregulation syndrome: implications for a dopamine hypothesis of bipolar disorder.

OBJECTIVE: Rational therapeutic development in bipolar is hampered by a lack of pathophysiological model. However, there is a wealth of converging data on the role of dopamine in bipolar disorder. This paper therefore examines the possibility of a dopamine hypothesis for bipolar disorder. METHOD: A literature search was conducted using standard search engines Embase, PyschLIT, PubMed and MEDLINE. In addition, papers and book chapters known to the authors were retrieved and examined for further relevant articles. RESULTS: Collectively, in excess of 100 articles were reviewed from which approximately 75% were relevant to the focus of this paper. CONCLUSION: Pharmacological models suggest a role of increased dopaminergic drive in mania and the converse in depression. In Parkinson's disease, administration of high-dose dopamine precursors can produce a 'maniform' picture, which switches into a depressive analogue on withdrawal. It is possible that in bipolar disorder there is a cyclical process, where increased dopaminergic transmission in mania leads to a secondary down regulation of dopaminergic receptor sensitivity over time. This may lead to a period of decreased dopaminergic transmission, corresponding with the depressive phase, and the repetition of the cycle. This model, if verified, may have implications for rational drug development.

[Sleep and wakefulness drugs and their indications]. / Les médicaments du sommeil et de la vigilance et leurs indications.

This paper is a review of the use of drugs in sleep and wakefulness disorders. Insomnia is more often a symptom than an autonomic disorder. Good knowledge of the clinical facts is required before prescribing hypnotics. Sedative drugs are potentially hypnotics; yet, melatonin is not sedative and may be considered to resynchronise of sleep phases. Stimulant drugs are prescribed in attention disorders; methylphenidate is the more frequently used. Narcolepsy, which is characterized by daytime sleepiness and irresistible episodes of sleep, is treated by an alpha1 noradrenergic stimulant modafinil which has no amphetaminic properties.

Effect of antidepressant drugs on 6-OHDA-treated mice in the FST.

There is growing evidence suggesting that dopamine could be indirectly involved in the appearance of behavioural effects of antidepressants. In this study, we induced a partial (over 70%) and non-reversible depletion of dopamine-containing neurons in mice by i.c.v. infusion of 6-OHDA. Then, we compared the antidepressant-like effect of drugs (citalopram, paroxetine, desipramine and imipramine) with or without dopamine depletion in the mice forced swimming test. Our results clearly show that lesion with 6-OHDA does not modify the response of mice to desipramine and imipramine, whereas dopamine depletion abolished the antidepressant-like effect of citalopram and paroxetine. It could then be suggested that antidepressant-like effect of selective serotonin reuptake inhibitors (paroxetine and citalopram) in the mice FST requires the activation of dopaminergic pathways to occur.

Antidepressant-like activity of selective serotonin reuptake inhibitors combined with a NK1 receptor antagonist in the mouse forced swimming test.

Substance P antagonists of the neurokinin-1 receptor type (NK1) have growing interest as new antidepressant therapies. It has been postulated that these drugs exert this putative therapeutic effect without direct interactions with serotonin (5-HT) neurons. In line with this assumption, previous intracerebral in vivo microdialysis experiments provided evidence that the NK1 receptor antagonists did not change basal cortical 5-HT levels. However, we found that increases in cortical 5-HT overflow caused by systemic injection of the selective serotonin reuptake inhibitor (SSRI), paroxetine was higher in freely moving (C57BL/6x129sv) NK1-/- mutants than in wild-type NK1+/+ mice. More recently, a pharmacological study has led to a similar conclusion since GR205171, a NK1 receptor antagonist, potentiated paroxetine-induced increases in cortical 5-HT dialysate following its acute systemic or intra-raphe administration to wild-type mice . In the present study, we tested whether an acute combination of SSRI and NK1 receptor antagonist could display antidepressant-like activity using the forced swimming test in Swiss mice. We found that a single systemic dose of GR205171 (10 and 30 mg/kg, i.p.) had no effect by itself. However, it selectively potentiated the antidepressant-like activity of subactive doses of two serotonergic antidepressant drugs, citalopram and paroxetine (without psychomotor stimulant activity), but not that of noradrenaline reuptake inhibitor, desipramine. In agreement with neurochemical data, the present study confirms that co-administration of a NK1 receptor antagonist with an antidepressant drug such as a SSRI may have a therapeutic potential to improve the treatment of major depressive episodes in human compared to SSRI alone.

Tumor necrosis factor alpha and glutathione interplay in chronic heart failure.

The pro-inflammatory cytokine, tumor necrosis factor alpha (TNF alpha), in concert with neurohormones, contributes to chronic heart failure (CHF) progression. This implies that TNF a antagonism may constitute an important target for CHF therapy. However, clinical trials in CHF patients using compounds that trap TNF alpha, comprising infliximab, an antibody directed to TNF alpha, and etanercept, a soluble recombinant receptor of TNF alpha, gave disappointing results bringing back to light the dual, short-term beneficial and long-term harmful effect of TNF alpha. This review focuses on the dual, concentration- and time-related effects of TNF alpha, the yin and yang action of TNF alpha in cardiac ischemia/reperfusion and contraction. Importantly, the harmful effects of TNF a are related to glutathione deficiency, a common hallmark to several other chronic inflammatory diseases. Recently, in rat models of CHF, oral administration of the glutathione precursor, N-acetylcysteine (NAC), was shown to hinder pathways of TNF alpha harmful signalling and to rescue cardiac structure and function. These results suggest that glutathione deficiency in association with TNF alpha activation may play a role in the pathophysiology of CHF and that NAC may represent a potential therapy in CHF.

A typical mood stabilizers: a "typical role for atypical antipsychotics.

OBJECTIVE: To assess the potential role of atypical antipsychotics as mood stabilizers. METHOD: A MedLine, PsychLIT, PubMed, and EMBASE literature search of papers published up to December 2004 was conducted using the names of atypical antipsychotics and a number of key terms relevant to bipolar disorder. Additional articles were retrieved by scrutinizing the bibliographies of review papers and literature known to the authors. Data pertinent to the objective was reviewed according to the various phases of bipolar disorder. RESULTS: The data is most substantive for the use of atypical antipsychotics in mania, to the extent that an argument for a class effect of significant efficacy can be made. This does not extend to bipolar depression, however, good data is now emerging for some agents and will need to be considered for each individual agent as it accumulates. As regards mixed states and rapid cycling the evidence is thus far sparse and too few maintenance studies have been conducted to make any firm assertions. However, with respect to long-term therapy the atypical antipsychotics do have clinically significant side-effects of which clinicians need to be aware. CONCLUSION: Based on the evidence thus far it is perhaps premature to describe the atypical antipsychotics as mood stabilizers. Individual agents may eventually be able to claim this label, however, much further research is needed especially with respect to maintenance and relapse prevention.

Effects of acute treatment with paroxetine, citalopram and venlafaxine in vivo on noradrenaline and serotonin outflow: a microdialysis study in Swiss mice.

1. This study investigated whether a single administration of a range of doses (1, 4 and 8 mg kg-1, i.p.) of paroxetine, citalopram or venlafaxine may simultaneously increase extracellular levels of 5-HT ([5-HT]ext) and noradrenaline ([NA]ext) by using in vivo microdialysis in the frontal cortex (FCx) of awake, freely moving Swiss mice. 2. In vivo, paroxetine induced similar increases in cortical [5-HT]ext at the three doses tested, and induced a statistically significant increase in cortical [NA]ext at 4 and 8 mg x kg-1. Citalopram increased neither [5-HT]ext nor [NA]ext at the lowest dose, but increased both neurotransmitter levels at 4 and 8 mg x kg-1. At these doses, citalopram induced greater increases in cortical [5-HT]ext than in [NA]ext. Venlafaxine increased [5-HT]ext and [NA]ext to about 400 and 140% of the respective basal values at 8 mg kg-1. 3. Citalopram and paroxetine have the highest potency to increase cortical [5-HT]ext and [NA]ext, respectively. In addition, the rank of order of efficacy of these antidepressant drugs to increase [5-HT]ext in vivo in the FCx of mice was as follows: venlafaxine>citalopram>paroxetine, while the efficacy to increase cortical [NA]ext in mice of paroxetine and citalopram is similar, and greater than that of venlafaxine. 4. In conclusion, extracellular levels of cortical [NA]ext increase with the highest doses of the very selective SSRI citalopram, as well as with the very potent SSRI paroxetine. Surprisingly, the SNRI venlafaxine increased cortical [5-HT]ext to a greater extent rather than [NA]ext in the range of doses studied in mice.

Effects of chronic paroxetine treatment on dialysate serotonin in 5-HT1B receptor knockout mice.

The role of serotonin (5-HT)1B receptors in the mechanism of action of selective serotonin re-uptake inhibitors (SSRI) was studied by using intracerebral in vivo microdialysis in conscious, freely moving wild-type and 5-HT1B receptor knockout (KO 5-HT1B) mice in order to compare the effects of chronic administration of paroxetine via osmotic minipumps (1 mg per kg per day for 14 days) on extracellular 5-HT levels ([5-HT]ext) in the medial prefrontal cortex and ventral hippocampus. Basal [5-HT]ext values in the medial prefrontal cortex and ventral hippocampus, approximately 20 h after removing the minipump, were not altered by chronic paroxetine treatment in both genotypes. On day 15, in the ventral hippocampus, an acute paroxetine challenge (1 mg/kg i.p.) induced a larger increase in [5-HT]ext in saline-pretreated mutant than in wild-type mice. This difference between the two genotypes in the effect of the paroxetine challenge persisted following chronic paroxetine treatment. Conversely, in the medial prefrontal cortex, the paroxetine challenge increased [5-HT]ext similarly in saline-pretreated mice of both genotypes. Such a challenge produced a further increase in cortical [5-HT]ext compared with that in saline-pretreated groups of both genotypes, but no differences were found between genotypes following chronic treatment. To avoid the interaction with raphe 5-HT1A autoreceptors, 1 micro m paroxetine was perfused locally through the dialysis probe implanted in the ventral hippocampus; similar increases in hippocampal [5-HT]ext were found in acutely or chronically treated wild-type mice. Systemic administration of the mixed 5-HT1B/1D receptor antagonist GR 127935 (4 mg/kg) in chronically treated wild-type mice potentiated the effect of a paroxetine challenge dose on [5-HT]ext in the ventral hippocampus, whereas systemic administration of the selective 5-HT1A receptor antagonist WAY 100635 did not. By using the zero net flux method of quantitative microdialysis in the medial prefrontal cortex and ventral hippocampus of wild-type and KO 5-HT1B mice, we found that basal [5-HT]ext and the extraction fraction of 5-HT were similar in the medial prefrontal cortex and ventral hippocampus of both genotypes, suggesting that no compensatory response to the constitutive deletion of the 5-HT1B receptor involving changes in 5-HT uptake capacity occurred in vivo. As steady-state brain concentrations of paroxetine at day 14 were similar in both genotypes, it is unlikely that differences in the effects of a paroxetine challenge on hippocampal [5-HT]ext are due to alterations of the drug's pharmacokinetic properties in mutants. These data suggest that there are differences between the ventral hippocampus and medial prefrontal cortex in activation of terminal 5-HT1B autoreceptors and their role in regulating dialysate 5-HT levels. These presynaptic receptors retain their capacity to limit 5-HT release mainly in the ventral hippocampus following chronic paroxetine treatment in mice.

CCK2 receptor-deficient mice have increased sensitivity of dopamine D2 receptors.

The present study supports a role of CCK(2) receptors in the regulation of dopamine neurones. In pharmacological studies conducted on male CCK(2) receptor-deficient mice the changes in the activity of dopamine system were established. A low dose of dopamine agonist apomorphine (0.1 mg/kg), stimulating the pre-synaptic dopamine receptors, induced significantly stronger suppression of locomotor activity in mutant mice (-/-) compared to their wild-type littermates (+/+). The administration of amphetamine (3-6 mg/kg), a drug increasing dopamine release, caused a dose-dependent stimulation of locomotor activity in wild-type mice. In mice lacking CCK(2) receptors, a lower dose of amphetamine (3 mg/kg) tended to suppress the motor activity, whereas the higher dose (6 mg/kg) induced the significantly stronger motor stimulation in mutant mice. Moreover, in the CCK(2) receptor-deficient mice the affinity of dopamine D(2) receptors, but not 5-HT(2) receptors, was increased. Altogether, the targeted genetic suppression of CCK(2) receptors increased the sensitivity of pre- and post-synaptic dopamine D(2) receptors.

[Characteristics of hypersensitivity syndrome to lamotrigine: review of one case reported in the Regional Center of Pharmacovigilance of Nantes]. / Caractéristiques du syndrome d'hypersensibilité à la lamotrigine: revue à partir d'un cas observé au CRPV de Nantes.

Drug-induced hypersensitivity syndrome is an uncommon but potentially life-threatening idiosyncratic drug reaction. In the literature, about five cases have been reported concerning hypersensitivity syndrome with lamotrigine. Most cases concern aromatic anticonvulsants but we report a case induced by lamotrigine which is a non aromatic anticonvulsant. A 73-year-old man was treated with lamotrigine for epilepsy due to a cerebrovascular stroke for 5 weeks. After 2 weeks with a single oral dose of 50 mg lamotrigine, the patient received 100 mg. Quickly thereafter fever, erythema and edema involving the periorbital area appeared. He was then admitted to hospital and lamotrigine was immediately discontinued. He developed acute hepatic and renal failure. During his hospital stay, he was treated with systemic and topical corticosteroids. After slow improvement, he was discharged 4 weeks later. Concerning this typical case, we review the characteristics of hypersensitivity syndrome and the different etiopathogenesis. The hypersensitivity syndrome typically develops two to six weeks after a drug is first administered, later than most other serious skin reactions. This syndrome manifests as rash, fever, tender lymphadenopathy, hepatitis and eosinophilia. The mechanism of hypersensitivity syndrome is unknown. Several theories have been proposed. The reaction is secondary to circulating antibodies or concerns toxic metabolities. On the other hand, association of human herpes virus 6 infection may play a role in the development of hypersensitivity syndrome. Hypersensitivity reactions to the aromatic antiepileptic drugs appear to have an immune etiology much like lamotrigine: bioactivation, detoxification, covalent adduct formation, processing and presentation of antigen to the immune system, and consequent formation of antibody and T-cell immune effectors. Another theory involves toxic metabolites; the aromatic antiepileptic agents are metabolised by cytochrome P-450 to an arene oxide metabolite. This is normally detoxified by epoxide hydrolase. This enzyme may be lacking or mutated in persons that develop the syndrome, and this is genetically determined. Lamotrigine is mainly metabolised by hepatic glucuronidation, but hypersensitivity may involve similar processes such aromatic antiepileptic drugs, except that the toxic metabolite has not yet been found. Because of slow evolution and clinical similarity to many infectious illnesses, the diagnosis of hypersensitivity syndrome may be delayed. Prompt recognition and withdrawal of the suspected drug is essential. The goal of research is to describe a "susceptibility profile" identifying individuals at risk for these forms of drug toxicity.

[Mechanism of action of antidepressants and therapeutic perspectives]. / Mécanisme d'action des antidépresseurs et perspectives thérapeutiques.

Depression is an incapacitating disease which needs appropriate treatment. This article reviews the pharmacology of antidepressant drugs and the future perspectives of treating mood disorders such as depression. The foremost theory for explaining the biological basis of depression has been the monoamine hypothesis. Depression is due to a deficiency in one or other biogenic monoamines (serotonin, 5-HT; noradrenaline, NA; dopamine, DA). Antidepressant drugs are therefore classified according to their ability to improve monoaminergic transmission. Since this first theory, other explanations based on abnormal function of monoamine receptors or associated with impaired signalling pathways have been suggested. Notable progress has been accomplished in the treatment of major depressive disorders with new compounds recently discovered (selective serotonin reuptake inhibitors: SSRI; serotonin noradrenaline reuptake inhibitors: SNRI). Behavioural, electrophysiological and microdialysis studies have shown that serotonin (5-HT) receptors, mainly 5-HT1A, 5-HT1B and 5-HT2C sub-types, exert a key role in modulating antidepressant activity. Indirect activation of neurotransmitter receptors by antidepressants may also lead, via increases in endogenous levels of serotonin in synapses in specific brain regions, to activation of various G proteins coupled to a receptor, signal of transduction, transcription factors and neurotrophic factors such as brain-derived neurotrophic factor (BDNF). Thus, depression may be considered as a transduction mechanism anomaly. This hypothesis needs to be clarified by molecular biology. Although antidepressants have improved the therapeutic potential compared to tricyclics (TCA) in terms of reduced side effects, a number of problems still occur with these drugs. Clinical effects are not always observed until after this time has elapsed (4-6 weeks) and a substantial proportion of depressed patients show only partial or no response to antidepressants. Knowledge of the existence of links between neurotransmitter systems and the discovery of the most specific target, 5-HT receptors, should lead to improvements in antidepressant therapy. Developing drugs using innovative mechanisms such as directly acting on 5-HT receptors (5-HT1A agonists or 5-HT2 antagonists), would appear to be useful in the treatment of depression. The use of antidepressants in anxiety disorders such as obsessional compulsive disorders and even generalised anxiety, highlights the distinction between antidepressants and classic anxiolytics such as benzodiazepines, or even buspirone.