New Drugs for Obesity Treatment / 대한내과학회지

There have recently been many advances in obesity treatment, including lifestyle modifications and pharmacological and surgical treatments. Specifically, pharmacological strategies have improved significantly. However, the history of the development of medications aimed at weight loss is complicated. The Federal Drug Administration (FDA) withdrew anti-obesity drugs such as fenfluramine, dexfenfluramine, and phenylpropylamine due to their unwanted side effects. Moreover, sibutramine was voluntarily withdrawn from the market and a new drug, rimonabant, has been suspended in the middle of a clinical trial due to unacceptable side effects. The FDA has approved four new anti-obesity drugs in recent years. Lorcaserin is a selective 5-hydroxytryptamine receptor 2c (5-HT2c) agonist. The pharmacological mechanism of action of this drug is similar to fenfluramine and dexfenfluramine, but lorcaserin is specific for 5-HT2c, which are located almost exclusively in the central nervous system and are not found in heart valves. Three phase 3 clinical trials for lorcaserin have been published recently; weight reduction was successful and no side effects involving the heart were found. Furthermore, the FDA has also approved phentermine/topiramate controlled-release (PHEN/TPM CR), which is composed of a combination of immediate-release phentermine and controlled-release topiramate. Weight reduction achieved with PHEN/TPM CR was demonstrated to be better than all other anti-obesity drugs. Lastly, the combination therapy bupropion/naltrexone activates proopiomelanocortin neurons and inhibits opioid-mediated negative feedback by synergism. Similar to liraglutide, a long-acting analogue of the hormone glucagon-like peptide-1, this treatment showed significant weight loss and metabolic improvements. However, in addition to its efficacy, clinicians should consider its side effects before use.

Weight Loss Drugs Recently Approved by the FDA / 임상당뇨병

There have been many advances in obesity treatment, including life-style modification and pharmacological and surgical treatments. It seems that the most remarkable advances in obesity treatment are those of pharmacological strategies. However, weight loss medications have a long history of development. The FDA has withdrawn anti-obesity drugs such as fenfluramine, dexfenfluramine, and phenylpropylamine due to unwanted side effects. Sibutramine was voluntarily withdrawn from the market, and new drugs such as rimonabant have been suspended in the middle of clinical study due to unacceptable side effects. Last year, the FDA approved two new anti-obesity drugs for the treatment of obesity. Lorcaserin is a selective 5-hydroxytryptamine receptor 2c (5-HT2c) agonist whose pharmacological mechanism of action is similar to those of fenfluramine and dexfenfluramine. However, lorcaserin is specific for 5-HT2c, which is located almost exclusively in the CNS and is not found on heart valves. Three exciting phase 3 clinical trials for lorcaserin have been published recently. Lorcaserin has been shown to successfully result in weight reduction, and the drug was not found to lead to heart disease, as is the case with some other such drugs. Furthermore, the FDA also approved controlled release phentermine/topiramate (PHEN/TPM CR), a drug composed of immediate-release phentermine and controlled-release topiramate. Weight reduction by PHEN/TPM CR is better than any other anti-obesity drugs in the world. Along with this excellent efficacy, however, come painful side effects that clinicians should consider.

Acute Manic Relapse with Dexfenfluramine

No abstract available.

Perspectivas no tratamento medicamentoso da obesidade / Perspectives of drug treatment of obesity

As perspectivas no tratamento medicamentoso da obesidade discutidaspodem ser divididas em duas categorias, a saber: medicamentos comercializados, em estudo clínico avançado ou em via deaprovação, ou drogas em início de investigação. Entre os primeiros destacam-se anticonvulsivantes como o topiramato (que embora tenha sido estudado na indicação de tratamento de obesidade foi descontinuado para esta indicação devido ao elevado número deabandono por efeitos adversos) e a zonisamida (com alguns estudosde curta duração em adultos obesos); antidepressivos como a bupropiona (que não somente leva a reduções de peso como minimiza o ganho de peso associado a cessação de tabagismo) e aradafaxina (metabólito da bupropiona, sem estudos documentados em obesos); análogos do glucagon-like peptide-1 como a exenatida (exendina-4), a pramlintida e a liraglutida (com estudos em diabéticos tipo 2 obesos) e um bloqueador seletivo do receptor canabinóide tipo 1, o rimonabant, cujos estudos (Rimonabant in Obesity), RIOEurope, RIO-North America, RIO-Lipids e RIO-Diabetes, envolvemmais de 6.600 pacientes com obesidade, com e sem diabetes e que se apresenta como perspectiva importante de tratamento da obesidade. Em início de investigação, estão moduladores da homeostase energética como antagonistas do neuropeptídeo Y, agonistas da melanocortina, leptina e análogos da leptina e fator neurotróficociliar (axokine); agentes termogênicos como os agonistas do receptor adrenérgico beta-3, agentes desacopladores da membranamitocondrial e moduladores periféricos da homeostase energética como a colecistoquinina.

Tratamento medicamentoso atual / Current obesity drug tratment

O tratamento farmacológico da obesidade é uma área de bruscasmudanças, desenvolvimento de novos produtos e propostas de tratamento. A informação apresentada nesta revisão oferece uma visão dos agentes fisiológicos, da terapêutica corrente, bemcomo de medicamentos amplamente usados e que não mais estão disponíveis.

Involvement of central serotonergic systems in dextromethorphan-induced behavioural syndrome in rats.

Dextromethorphan, a noncompetitive blocker of the N-methyl-D-aspartate (NMDA) type of glutamate receptor, at 45, 60 and 75 mg/kg, ip doses induced a behavioural syndrome characterised by reciprocal forepaw treading, lateral head-weaving, hind-limb abduction and flat body posture. Such type of behavioural syndrome is induced by 8-hydroxy-2- (di-n-propylamino) tetralin (8-OH-DPAT) by directly stimulating the central postsynaptic 5-hydroxytryptamine (5-HT, serotonin) receptors of the 5-HT1A type. Pretreatment with buspirone (5, 10 mg/kg, ip) and l-propranolol (10, 20 mg/kg, ip) antagonised the behavioural syndrome induced by 8-OH-DPAT and dextromethorphan. Pretreatment with p-chlorophenylalanine (100 mg/kg/day x 4 days) antagonised the behavioural syndrome induced by dextromethorphan and dexfenfluramine but had no significant effect on 8-OH-DPAT induced behavioural syndrome. This indicates that dextromethorphan induces the behavioural syndrome by releasing 5-HT from serotonergic neurons with resultant activation of the postsynaptic 5-HT1A receptors by the released 5-HT. Pretreatment with fluoxetine (10 mg/kg, ip) significantly potentiated the behavioural syndrome induced by dextromethorphan and 5-hydroxytryptophan but significantly antagonised dexfenfluramine induced behavioural syndrome. This indicates that dextromethorphan releases 5-HT by a mechanism which differs from that of dexfenfluramine. Dextromethorphan may be releasing 5-HT by blocking the NMDA receptors and thereby counteracting the inhibitory influence of l-glutamate on 5-HT release.

Effects of dexfenfluramine on dopamine dependent behaviours in rats.

5-hydroxytryptamine (5-HT) inhibits the synthesis and release of dopamine (DA) from rat nigrostriatal DAergic neurons. Dexfenfluramine releases 5-HT from brain 5-HTergic neurons. The present study was undertaken to determine whether dexfenfluramine, through the released 5-HT, modulates the intensity of the behaviours dependent on the functional status of the nigrostriatal DAergic system. The effect of pretreatment with dexfenfluramine on dexamphetamine and apomorphine stereotypies of the oral movement variety and on catalepsy induced by haloperidol and small doses (0.05 and 0.1 mg/kg ip) of apomorphine was studied in rats. We also investigated whether dexfenfluramine induces catalepsy in rats. Dexfenfluramine at 2.5, 5 and 10 mg/kg ip did not induce catalepsy and did not antagonise apomorphine stereotypy. However, 1 h pretreatment with 5-HT releasing doses of dexfenfluramine ie 5 and 10 mg/kg ip, antagonized dexamphetamine stereotypy and potentiated catalepsy induced by haloperidol and small doses of apomorphine. Our results, that dexfenfluramine at 2.5, 5 and 10 mg/kg ip neither induced catalepsy nor antagonised apomorphine stereotypy, indicate that dexfenfluramine at these doses does not block the postsynaptic striatal D2 and D1 DA receptors. They also indicate that the 5-HT released by 5 and 10 mg/kg dexfenfluramine does not exert an inhibitory effect at or beyond the postsynaptic striatal D2 and D1 DA receptor sites. However, 5 and 10 mg/kg doses of dexfenfluramine, through the released 5-HT, inhibit the synthesis and release of DA from the nigrostriatal DAergic neurons and thus antagonise dexamphetamine stereotypy and potentiate catalepsy induced by haloperidol and small doses of apomorphine.

Anorexígenos: indicaciones e interacciones / Anorexigens: indications and interactions

Antecedentes: Los anorexígenos generalmente no suelen ser de manejo habitual en la práctica clínica psiquiátrica. Sin embargo, es frecuente indicar una amplia gama de psicofármacos a pacientes a los cuales se les ha prescrito medicamentos supresores del apetito por otros profesionales. Esta combinación farmacológica implica una serie de aspectos a considerar en relación a las indicaciones, efectos adversos y fundamentalmente las interacciones propias de los agentes anorexígenos que en algunos casos pueden llegar a provocar complicaciones irreversibles y fatales. Objetivo. Puesta al día de los principales fármacos anorexígenos disponibles en Chile describiendo su clasificación, características, farmacocinética, indicaciones, contraindicaciones, efectos adversos e interacciones. Material y métodos. Revisión actualizada de la literatura especializada. Resultados. Los anorexígenos son coadyuvantes en el tratamiento integral de pacientes obesos. El resultado del tratamiento es mejor si se acompaña de una recuperación de los hábitos alimentarios. Poseen un alto potencial de abuso, dependencia, tolerancia y síndrome de privación. Sus principales efectos son cardiovasculares, gastrointestinales y en el sistema nervioso central. Los más utilizados en Chile entre 1997 y 1998 fueron fetermina, dietilpropión, fenproporex y dexfenfluramina. Discusión. La principal indicación de los anorexígenos es la obesidad. Deben ser prescritos exclusivamente por médicos. Se recomienda su indicación a corto plazo. Poseen importantes interacciones a considerar con IMAOs, ISRSs, descongestionantes, antitusígenos, antialérgicos, anestésicos generales, sustancias ilícitas, alcohol y otras drogas metabolizadas por citocromo P450. Se enfatiza la posibilidad de la producción del síndrome serotoninérgico. Chile, Argentina y Brasil se encuentran entre los principales países consumidores de estimulantes

Possible thermogenesis with dexfenfluramine.

Fifty obese patients with a body mass index greater than 25 kg/m2 were randomized into 3 groups: control (C = 19), placebo (P = 18) and dexfenfluramine (D = 18). A behavioral modification program which included eating habits, exercise, attitudes, social relationships and six steps to lifetime weight control was taught every week. All patients strictly followed the food manual and recorded their behavior, physical activity and food intake every day through 12 weeks. Placebo and dexfenfluramine 30 mg/day were given in a double blind placebo controlled study. The results showed that all 3 groups had significant decreases in rest times and increased activity times (p < 0.05) and significant reductions of the average total daily energy, carbohydrate and fat intake (p < 0.05). They all lost weight. Mean +/- SEM cumulative weight loss was 8.3 +/- 0.7 kg in group D, 3.3 +/- 1 kg, in group P and 2.9 +/- 0.7 kg, in group C. The mean additional weight loss of 5 kg, and 5.4 kg seen with dexfenfluramine being highly significant (p < 0.001) from group P and C most likely due to increased thermogenesis. Significant (p < 0.05) and gradual reduction of biceps, triceps skinfold and per cent body fat were constantly observed only in the dexfenfluramine group. There were no significant differences among the 3 groups regarding blood pressure, heart rate, hematologic, lipids and biochemical profiles.

Psicoterapia y farmacoterapia en el tratamiento de los trastornos de personalidad / Psychotherapy and pharmacotherapy in the treatment of personality disorders

Presentamos la transcripción de un Coloquio efectuado acerca del lugar que ocupan la psicoterapia y farmacoterapia en el tratamiento de los trastornos de personalidad. El coloquio muestra los diferentes argumentos, empíricos, clínicos y teóricos, que fundamentan la indicación de uno u otro método en cada caso particular. Desde el punto de vista de la farmacoterapia, que presentan las evidencias que apoyan un sustrato neurobiológico para los trastornos de personalidad. Especial énfasis es otorgado a las relaciones que existirían entre sistemas de neurotransmisión, dimensiones de personalidad, presentación clínica y respuesta a farmacoterapia. Asimismo, son examinados los problemas teóricos que supone clasificar los trastornos de personalidad en base a criterios puramente categoriales. Desde el punto de vista de la psicoterapia se examinan diversos aspectos de ella en relación a los trastornos de personalidad: su indicación, su relación e integración con otras formas de tratamiento (p.ej. farmacoterapia); su implementación en el ámbito institucional y las formas de cooperación multi e interdisciplinaria. Se examina asimismo la función de la psicoterapia como un marco de referencia que otorga sentido, no sólo a los conflictos del paciente, sino al conjunto de intervenciones efectuadas. Finalmente, se examina el problema del monismo vs dualismo metódico y sus implicancias para la praxis futura