Problemas relacionados a medicamentos; reações adversas a medicamentos e erros de medicação: a necessidade de uma padronização nas definições e classificações / Drug Related Problems; Adverse Drug Reaction, Medication Errors: The requirement of an uniform definition and classification

Problemas Relacionados a Medicamentos (PRMs) é um termo freqüentemente utilizado na Atenção Farmacêutica e na Farmácia Clínica. Os PRMs podem estar relacionados a Reações Adversas a Medicamentos (RAMs), consideradas não evitáveis e que sempre produzem dano ao paciente, ou Erros de Medicação (EM), considerados evitáveis e que podem ou não causar danos ao paciente. Os EM classificam-se em erros de prescrição, dispensação e administração. Uma proposta de classificação adaptada da PCNE (Pharmaceutical Care Network Europe) é descrita neste artigo.

Drug Related Problems (DRPs) is a term often used in pharmaceutical care and in the clinical pharmacy. Drug Related Problems can be related to Adverse Drug Reactions (ADRs) that are considered unavoidable and always induce harm and Medication Errors (MEs), considered avoidable and may or not induce harm. Medication Errors are classified in prescribing, dispensing and administration errors. A proposal for classification adapted from the Pharmaceutical Care Network Europe (PCNE) is described in this article.

Characterization of the interdependency between residues that bind the substrate in a â-glycosidase

The manner by which effects of simultaneous mutations combine to change enzymatic activity is not easily predictable because these effects are not always additive in a linear manner. Hence, the characterization of the effects of simultaneous mutations of amino acid residues that bind the substrate can make a significant contribution to the understanding of the substrate specificity of enzymes. In the â-glycosidase from Spodoptera frugiperda (Sfâgly), both residues Q39 and E451 interact with the substrate and this is essential for defining substrate specificity. Double mutants of Sfâgly (A451E39, S451E39 and S451N39) were prepared by site-directed mutagenesis, expressed in bacteria and purified using affinity chromatography. These enzymes were characterized using p-nitrophenyl â-galactoside and p-nitrophenyl â-fucoside as substrates. The k cat/Km ratio for single and double mutants of Sfâgly containing site-directed mutations at positions Q39 and E451 was used to demonstrate that the effect on the free energy of ES‡ (enzyme-transition state complex) of the double mutations (∆∆G‡xy) is not the sum of the effects resulting from the single mutations (∆∆G‡x and ∆∆G‡y). This difference in ∆∆G‡ indicates that the effects of the single mutations partially overlap. Hence, this common effect counts only once in ∆∆G‡xy. Crystallographic data on â-glycosidases reveal the presence of a bidentate hydrogen bond involving residues Q39 and E451 and the same hydroxyl group of the substrate. Therefore, both thermodynamic and crystallographic data suggest that residues Q39 and E451 exert a mutual influence on their respective interactions with the substrate.