Tolerabilidad de Aspirina / Aspirin tolerability

El ácido acetilsalicílico (AAS) es un fármaco profusamente utilizado en todo el mundo, presente tanto en preparados que requieren prescripción médica como en productos de libre dispensación, sea en formulaciones que lo contienen como único principio activo, sea como parte de asociaciones a dosis fija. Se emplea tanto de forma puntual, en indicaciones agudas, sintomáticas, como de forma continuada en los regímenes profilácticos anti-trombóticos. Así pues, es muy importante disponer de una sustancia bien tolerada y segura, por su perfil de reacciones adversas y capacidad para interaccionar con otros fármacos. Ambos rasgos son particularmente importantes cuando la población expuesta al fármaco es de cierta edad, debido a sus particulares características que aumentan la susceptibilidad ante reacciones adversas y sus complicaciones. Aspirina comparte el perfil general de reacciones adversas de los AINE, de los que se considera el fármaco prototipo. Administrada de forma aguda, la incidencia de reacciones adversas, por lo general leves, parece similar a la de otros analgésicos. Destacan por su frecuencia los efectos sobre el tracto gastrointestinal, habiéndose detectado una serie de factores de riesgo para el desarrollo de complicaciones graves de las lesiones digestivas. La consideración de estos factores de riesgo junto con la toma de medidas profilácticas, puede disminuir su morbimortalidad. En los últimos años se ha prestado especial atención a las reacciones de hipersensiblidad, destacando el asma inducido por Aspirina, que puede ser cruzado con otros AINE de uso, asimismo, frecuente. El sector de la población más susceptible a presentar reacciones de tipo asmático, presenta unos rasgos bien definidos. Las propiedades antiagregantes de Aspirina pueden complicar ciertas situaciones en que la hemostasia está comprometida, no obstante, se ha demostrado su beneficio en la prevención de accidentes vasculares de carácter atero-trombótico. El síndrome de Reye es un cuadro de rara presentación, pero de graves consecuencias, que contraindica el uso de Aspirina en niños o adolescentes con fiebre o ciertas infecciones virales. Dada la extensa utilización de Aspirina, puede ser considerado un fármaco bien tolerado en general, cuyas reacciones adversas más graves deben ser objeto de una especial farmacovigilancia, prestando especial atención a la población de mayor riesgo. Esta situación aconseja, asimismo, la puesta en marcha de programas de educación sanitaria sobre el uso de los analgésicos. En todo caso, Aspirina sigue siendo un fármaco de referencia con una importante potencialidad terapéutica derivada de los beneficios inherentes a su uso (AU)

The acetylsalicylic acid (ASA) is a widely used drug worldwide, both as prescription and over-the-counter products, and both as the only active drug or associated to other drugs in fixed doses. It is used either occasionally for the management of acute symptomatic conditions, or continuously in prophylactic anti-thrombotic regimes. Its profile of adverse reactions and potential interactions with other drugs makes it very important to have a well-tolerated and safe substance. Both things are particularly relevant when the population exposed to this drug has reached a certain age, since its specific features may increase its susceptibility to side effects and complications. Aspirin shares the general profile of adverse reactions of the NSAIs and it is considered as its prototype. When acutely administered, the incidence of side effects, most of them light, are the same as with other analgesics. Gastrointestinal effects are the most frequent of all and several risk factors have been identify for the development of severe gastrointestinal complications. These risk factors must be considered along with the need to take prophylactic measures in order to reduce the morbi-mortality. In recent years, special attention has been devoted to hypersensitivity reactions, in particular Aspirin-induced asthma, and potential cross-reactions with other frequently used NSAIs. The most susceptible sub-population for asthmatic reactions has well-defined features. The anti-aggregation effects of Aspirin can complicate some conditions associated to hemostasis disorders; however, its benefit has been shown for the prevention of athero-thrombotic vascular accidents. The Reye´s Syndrome is a rare but severe condition in which the use of Aspirin is contraindicated in children or adolescents with fever or certain viral infections. Given the extensive use of Aspirin, it can generally be considered a well-tolerated drug whose most severe adverse reactions require special pharmacovigilance, as well as special attention to high risk populations. This also suggests the need to implement health education programs about the use of analgesics. In any case, Aspirin is still a reference drug with a high therapeutic potential derived from the benefits provided by its use (AU)

Antinociceptive effects of tricyclic antidepressants and their noradrenergic metabolites.

This study evaluates the antinociceptive effect of several tricyclic antidepressants in four nociceptive tests which employ either thermal (hot plate and tail flick tests) or chemical (formalin and acetic acid tests) stimuli. Forced swimming test was also performed as a model of depression and an activity test was also performed. Mixed antidepressants in current clinical use: amitriptyline, imipramine and clorimipramine and their respective main secondary metabolites which preferentially inhibit noradrenaline reuptake: nortriptyline, desipramine and desmethylclorimipramine, were tested (2.5-20 mg/kg, i.p.) in mice. The results show a stronger antinociceptive effect in chemical tests induced by all the drugs, compared with thermal tests. The doses needed to produce antinociception were lower than those inducing an antidepressive effect, both effects being mutually independent. The overall results show that preferentially noradrenergic tricyclics induced an antinociceptive effect comparable with that of mixed tricyclics, indicating that noradrenaline reuptake plays an important role in tricyclic-induced antinociception.

¿Tienen algún papel los cannabinoides en el tratamiento del dolor? / Is there a place for cannabinoids in the management of pain?

No disponible

Interacciones de metadona con fármacos antiinfecciosos y sustancias de abuso / Methadone interactions with anti infectious drugs and abuse substances

Frecuentemente es necesario utilizar fármacos antiinfecciosos en pacientes tratados con metadona. Se han observado diversas interacciones entre metadona y fármacos antiinfecciosos , siendo necesaria una especial vigilancia en caso de tratamiento antirretroviral. Se ha descrito aumento de los niveles plasmáticos y de la toxicidad de zidovudina por metadona; también es posible el efecto contrario, es decir la disminución de los efectos del opiáceo por la zidovudina. Entre los inhibidores de la proteasa, ritonavir puede aumentar considerablemente los niveles plasmáticos de metadona y sus efectos depresores. Eritromicina o ketoconazol tienen efectos farmacocinéticos similares. Al contrario, se ha observado el desencadenamiento de síndrome de abstinencia debido a inducción metabólica originada por rifampicina. También las sustancias de abuso, frecuentemente utilizadas por estos pacientes, pueden originar interacciones farmacológicas. La significación clínica de la interacción alcohol/metadona no está clara, en ella pueden participar modificaciones en el metabolismo hepático. A pesar del extenso abuso de cocaína en estos pacientes, son poco conocidas las consecuencias de su consumo con metadona, en las que pudieran estar implicadas interacciones entre la neurotransmisión catecolaminérgica y opioidergica. Se requieren más estudios sobre cannabinoides, anfetaminas o drogas de diseño, de frecuente consumo en esta población (AU)

[Drug interactions of methadone with CNS-active agents]. / Interacciones medicamentosas de metadona con psicofármacos.

Psychoactive medication is frequently used in methadone maintenance treatment programs (MMP) to treat comorbid mental disorders (depression, anxiety, schizophrenia) in opiate-addicts. Thus, several pharmacological interactions are possible. This problem becomes more relevant with the introduction of new CNS-drugs like SSRI, atypical antipsychotics or new anticonvulsants. The most common interactions seen in practice are pharmacodynamic in nature, most often due to the cumulative effects of different drugs on the central nervous system (e.g. neuroleptics or benzodiazepine interactions). However important pharmacokinetic interactions may occur particularly between methadone and antidepressant drugs: Desipramine plasma levels are increased by methadone; further fluvoxamine (and fluoxetine to a less extent) may cause an important increase in serum methadone concentrations. The inhibition of different clusters of the cytochrome P450 system are involved in these interactions. Several lines of evidence suggest that benzodiazepines and methadone may have synergistic interactions and that opiate sedation or respiratory depression could be increased. This is a serious problem, given the widespread use of benzodiazepines among MMP patients. Experimental but not clinical data support methadone and lithium interactions. Finally, classic anticonvulsant drugs, such as phenytoin, carbamazepine and phenobarbital, produce dramatic decreases in methadone levels, which may precipitate a withdrawal syndrome; valproic acid and the new anticonvulsant drugs do not have these effects. Accordingly, caution is advised in the clinical use of methadone when other CNS-drugs are administered.

[Prescription habits in a primary health care district: approach to an indication-prescription study]. / Hábitos de prescripción en un distrito de atención primaria de salud. Aproximación a un estudio de indicación-prescripción.

OBJECTIVE: To analyse the profile of medical prescription and prescription habits in the most common illnesses in a Primary Health Care district. DESIGN: Descriptive crossover study. SETTING: Algeciras-La Línea (Cádiz) Primary Care district. MEASUREMENTS AND MAIN RESULTS: A randomised sample of clinical histories stratified by months was selected. This included 338 Paediatrics cases (< 8 years old) and 665 general medical cases (> 8). The therapeutic groups most commonly prescribed for the children were R (45.7%) and J (27.1%) The therapeutic groups most used among the > 8 group were C (17.9%), R (14.8%), N (14.7%) and A (14.3%). Hypertension was the most common chronic pathology in this group (8.9%), treated most often by ACEIs (44.9%). CONCLUSIONS: 1) In our ambit, the most widespread pathology signified the greatest consumption of therapeutic groups. 2) The indication-prescription analysis detected prescription habits that need to be watched: the use of antibiotics and expectorants/mucolytics in ARI and the use of fixed-dose combinations which are hard to justify. Prescription habits in Hypertension treatment and Hyperlipidaemia also merit a consensus analysis.

Influence of antidepressant drugs administration on the morphine inhibitory effect in mice vasa deferentia.

The effect of chronic and acute antidepressant drug administration on peripheral opioid mechanisms was investigated. For this purpose, the inhibitory effect of morphine on electrically-induced contractions of mouse vas deferens was measured. Acute antidepressant administration did not induce any change in morphine inhibition. Chronic fluvoxamine and chlorimipramine treatment induced strong and significant hypersensitivity to morphine-inhibition. Chronic desipramine, desmethylclomipramine and nortriptyline treatment induced the opposite effect. These results seem to show differential opioidergic regulation depending on the monoaminergic antidepressant used. The level of this interaction remains to be elucidated.