Relevancia clínica de las interacciones medicamentosas en pacientes infectados con el virus de la inmunodeficiencia humana: actualización 2009-2014 / The clinical relevance of drug interactions in patients with human immunodeficiency virus infection: update 2009-2014

Objective: To update information about drug interactions in patients with HIV/AIDS. Methods: Comprehensive literature review in MEDLINE/PubMed database from May of 2009 to December of 2014, using the Mesh terms: Anti-retroviral agents and drug interactions or herb-drug interactions or food-drug interactions. Publications with drug interactions in humans, in English or Spanish, and with full text were retrieved. Additionally, citation lists from identified articles were reviewed. The study inclusion was assessed by three independent researchers and by consensus among them when was necessary. Clinical relevance of drug interaction was grouped into four levels according to seriously and probability of occurrence. Results: Global, 546 different references were retrieved and 243 were selected. In addition 11 further manuscripts were identified in the references of the included articles. Overall, 935 pairs of drug interactions were identified, 95.7% pharmacokinetic (823 by enzyme induction or inhibition and 67 by changes in bioavailability). Of the 935 pairs of drug interactions, 402(43%) were classified as levels 1 or 2. Conclusions: The most clinically relevant antiretroviral drug interactions are due to pharmacokinetic mechanism, mainly induction or enzyme inhibition, according to previous reviews, the protease inhibitors remain as the antiretrovirals with the highest number of clinical relevant interactions.

Objetivo: Actualizar información sobre interacciones medicamentosas en pacientes con VIH/SIDA. Métodos: Revisión estructurada en MEDLINE/PubMed utilizando los términos Mesh: Anti-retroviral agents and drug interactions or herb-drug interactions or food-drug interactions, entre mayo de 2009 y diciembre de 2014. Publicaciones sobre interacciones medicamentosas, en humanos, en inglés o español y con acceso a texto completo fueron seleccionadas. Además, se incluyeron referencias de artículos considerados relevantes. La inclusión de los artículos fue evaluada por tres investigadores independientes y, en caso de requerirlo, por consenso entre ellos. La relevancia clínica se estableció en cuatro niveles, acorde con la gravedad y probabilidad de ocurrencia de la interacción. Resultados: Se identificaron 546 artículos, de los cuales se seleccionaron 273; además, se incluyeron 11 referencias relevantes. Se identificaron 935 parejas de interacciones medicamentosas, 95,7% farmacocinéticas. De este grupo, 823 mediadas por inducción o inhibición enzimática y 67 por cambios en la biodisponibilidad. De las 935 parejas de interacciones, 402 (43%) fueron relevantes clínicamente (niveles 1 o 2). Conclusiones: Las interacciones medicamentosas con anti-retrovirales de mayor relevancia clínica se deben a mecanismos farmacocinéticos, principalmente inducción o inhibición enzimática. Acorde con revisiones previas, los inhibidores de proteasa continúan siendo los anti-retrovirales con mayor número de interacciones relevantes.

Comparison of levels of antiretroviral drugs with efficacy in children with HIV infection.

Objective. To determine the prevelance of low and high antiretroviral (ARV) plasma levels and to analyze correlation between ARV concentrations and the appearance of therapeutic failure and toxicity. Methods. The authors present here a study evaluating antiretroviral plasma concentrations in HIV infected children on nonnucleoside reverse transcriptase inhibitors and protease inhibitors based therapy. The authors carried out a multicentre, crosssectional study, including HIV-infected children from five large Hospitals in Madrid, Spain. Clinical, haematological, biochemical and immuno-virological parameters were assessed. Antiretroviral plasma trough levels were performed using a validated high performance liquid chromatography method. Results. Between April 2006 and April 2008, 129 children were enrolled in the present study, with median treatment duration of 39.2 months. 25.5% of the non-nucleoside reverse transcriptase inhibitors levels were low and 17.6%, high. 27.9% percent of the protease inhibitors levels were low and 12.5%, high. A correlation was found among adequate or high levels of antiretrovirals and normal CD4 percentage and low viral load. Lopinavir/ritonavir plasma levels were correlated with an increase in lipodystrophy. Patients with Tanner stage 1 presented the lowest ARV plasma levels. Full adherence was reported for all the participants by a questionnaire. Conclusion. Many HIV-infected children show ARV plasma levels out of the therapeutic range which demands a child-adjusted approach. However, larger studies are urgently needed in pediatric populations to define optimal reference values.

Reversed phase HPLC determination of zidovudine in rat plasma and its pharmacokinetics after a single intranasal dose administration

The development and validation of a simple and accurate method based on HPLC with ultraviolet detection for the quantification of zidovudine in rat plasma and its application to a pharmacokinetic study following a single intranasal dose zidovudine is described. Zidovudine was extracted from the plasma using a single-step deproteinization. Chromatographic separation of zidovudine from interfering components was achieved with a C-18 reverse phase column, a mobile phase consisting of a mixture of sodium acetate buffer (55mM) with pH adjusted to 7.0 and acetonitrile (91:9 v/v) and UV detection set at 265 nm. The method was linear from 100 to 10000 ng.mL"¹ (r² > 0.9995), and zidovudine had a mean recovery from plasma of 92.8 percent. The coefficient of variation of inter-day and intra-day quality control samples was less than 15 percent. After a single intranasal dose of zidovudine administered to rats, pharmacokinetic parameters (AUC0 24, Cmax, t , t1/2) were determined. The proposed method was found to be simple, specific, accurate, and precise and could be applied to the quantitative analysis of clinical pharmacokinetic studies of zidovudine in rats.