[Acute hepatitis due to Exolise, a Camellia sinensis-derived drug].
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Acute Disease↗
Biomedical subjects
Jacques Descotes
Publications and source records attributed to Jacques Descotes.
Allergic adverse reactions to sulfonamides.
Antimicrobial sulfonamides were the first antimicrobial agents used effectively to treat infectious diseases. However, because they may cause severe adverse drug reactions (ADRs) and because more effective agents have since been developed, sulfonamides now are used for only a few indications in specific groups, such as AIDS patients. Skin reactions, from benign rash to potentially lethal toxidermias, are the most frequent ADRs to sulfonamides. Other major ADRs include acute liver injury, pulmonary reactions, and blood dyscrasias. Although the mechanisms involved have not been fully elucidated, reactive metabolites appear to play a pivotal role. The hydroxylamine and nitroso metabolites of sulfamethoxazole, the most frequently used sulfonamide today, can bind covalently to proteins because of their chemical reactivity, resulting in the induction of specific adverse immune responses. Therefore, changes in the activity of metabolic and detoxification pathways are associated with a greater risk for developing allergic reactions to sulfonamides. Allergies to sulfonamides, particularly sulfamethoxazole (often used in combination with trimethoprim as co-trimoxazole), are more frequent in AIDS patients, but the reason for this increased risk is not fully understood. No valid tools are available to predict which patients have a greater risk for developing allergies to sulfonamides. Diagnosis is essential to avoid a possible evolution toward severe reactions and readministration of the offending drug. In patients who absolutely require further treatment, successful desensitization may be achieved.
Anti-Infective Agents↗
Low-molecular-weight heparins and thrombocytosis.
BACKGROUND: A possible association between low-molecular-weight heparins (LMWHs) and thrombocytosis was suspected from spontaneous reports to the French Pharmacovigilance System. This association is not mentioned in LMWH's summary of product characteristics. METHODS: All case records in the French Pharmacovigilance database were reanalyzed for relevance and causality, and the case/noncase approach was used including reports of thrombocytosis as cases and all other reports as noncases. RESULTS: Fifty-one patients treated with LMWHs had platelet counts >500 x 10(3)/mm(3). All patients were asymptomatic, and 1 had a positive rechallenge. There were 143 cases of thrombocytosis among the 174 213 reports in the database, with 61 of 4644 involving LMWHs. The calculated relative reporting ratio is 27.5 (p < 0.0001; 95% CI 19.5 to 38.9). CONCLUSIONS: There is a highly significant association of thrombocytosis reported with LMWH treatment.
Adolescent↗
Popliteal lymph node assay: facts and perspectives.
The popliteal lymph node assay (PLNA) derives from the hypothesis that some supposedly immune-mediated adverse effects induced by certain pharmaceuticals involve a mechanism resembling a graft-versus-host reaction. The injection of many but not all of these compounds into the footpad of mice or rats produces an increase in the weight and/or cellularity of the popliteal lymph node in the treated limb (direct PLNA). Some of the compounds known to cause these adverse effects in humans, however, failed to induce a positive PLNA response, leading to refinements of the technique to include pretreatment with enzyme inducers, depletion of CD4(+) T cells or additional endpoints such as histological examination, lymphocyte subset analysis and cytokine fingerprinting. Alternative approaches have been used to improve further the predictability of the assay. In the secondary PLNA, the test compound is injected twice in order to illicit a greater secondary response, thus suggesting a memory-specific T cell response. In the adoptive PLNA, popliteal lymph node cells from treated mice are injected into the footpad of naive mice; a marked response to a subsequent footpad challenge demonstrates the involvement of T cells. Finally, the reporter antigens TNP-Ficoll and TNP-ovalbumin are used to differentiate compounds that induce responses involving neo-antigen help or co-stimulatory signals (modified PLNA). The PLNA is increasingly considered as a tool for detection of the potential to induce both sensitization and autoimmune reactions. A major current limitation is validation. A small inter-laboratory validation study of the direct PLNA found consistent results. No such study has been performed using an alternative protocol. Other issues include selection of the optimal protocol for an improved prediction of sensitization vs autoimmunity, and the elimination of false-positive responses due to primary irritation. Finally, a better understanding of underlying mechanisms is essential to determine the most relevant endpoints. The confusion resulting from use of the PLNA to predict autoimmune-like reactions as well as sensitization should be clarified. Interestingly, most drugs that were positive in the direct PLNA are also known to cause drug hypersensitivity syndrome in treated patients. This observation is expected to open new avenues of research.
Adoptive Transfer↗
Paclitaxel hypersensitivity reactions: assessment of the utility of a test-dose program.
UNLABELLED: Several studies have suggested the usefulness of a test dose of paclitaxel to reduce the incidence of hypersensitivity reactions and the resulting cost of drug wastage. The aim of this study was to assess the utility of implementing such a test dose. METHOD: We retrospectively reviewed the medical charts of patients who had received one or two courses of single-agent paclitaxel or a combination chemotherapy regimen to calculate hypersensitivity reaction incidence and the cost of drug wastage. Thereafter, a paclitaxel test-dose program was routinely implemented during the first and second cycles of paclitaxel treatment for all patients. Hypersensitivity reaction incidence and drug wastage cost were again assessed. RESULTS: Before the routine use of a test dose, 162 patients received one or two paclitaxel infusions alone or in combination therapy from January 1, 1997 to February 28, 2003. Ten (6.2%) patients experienced a hypersensitivity reaction; one of them was severe. After implementation of the test-dose program, 130 patients received 244 test doses (12 mg paclitaxel/10 mL normal saline) with an intensified premedication regimen at the first and second cycles of chemotherapy from June 28, 2003 to March 2, 2005. Three patients (2.3%) experienced a minor hypersensitivity reaction, one immediately after the test dose and two during infusion of the full dose despite a well-tolerated test dose. Thus, the negative predictive value of the test dose was 98.4%. The overall incidence of hypersensitivity reactions experienced during the first or second cycle of paclitaxel chemotherapy decreased about 63% compared with the incidence before implementation of the test dose (P < 0.20). The test-dose program resulted in a 29% increase in the cost of chemotherapy (approximately 6100 dollars for 130 patients). CONCLUSION: To our knowledge, this is the largest study ever reported to test the potential cost-saving benefit of the implementation of a paclitaxel test-dose program to prevent hypersensitivity reactions. The results suggest that the routine use of a test dose is not a cost-effective measure.
Adult↗
[Preclinical evaluation of the safety of biotechnology products: specific aspects].
Biotechnology-derived products represent a class of increasingly numerous drugs. One of their major characteristics is extreme diversity, which requires specific approaches for the preclinical evaluation of their safety. The selection of relevant animal species is not easy, as most of these products are human-specific. Thus, only one species will often be used, i.e. primates. As most of these products are large molecules, they can be directly immunogenic. When they are human-specific, no animal model is available to predict the risk. Many biotechnology-derived products have an expected influence on the immune system. This must be taken into account in the preclinical strategy of immunotoxicity evaluation that is now required for every new drug. As conventional toxicity testing is generally limited, safety pharmacology studies should include more than the core battery of assays required by current guidelines in order to complement missing data as much as possible. Because of these particularities, a comprehensive investigation of metabolism and pharmacokinetics is not usually needed. Some products can cross-react with cellular components not intended as therapeutic targets. It is, therefore, essential to rule out the risk of possible cross-reactions that can result in adverse effects. Finally, viral safety is a crucial component of the preclinical safety evaluation of these products. Overall, biotechnology-derived products raise specific issues because of their innovative and original characteristics, and it is difficult to address all these issues if not by using a case-by-case approach.
Animals↗
[Severe and unusually prolonged acute poisoning with primidone suggesting the presence of bezoars].
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Anticonvulsants↗
Autoimmune diseases and vaccinations.
The potential association between vaccination and autoimmune diseases has been largely questioned in the past few years, but this assumption has mostly been based on case reports. The available evidence derived from several negative epidemiological studies is reassuring and at least indicates that vaccines are not a major cause of autoimmune diseases. However, there are still uncertainties as to whether a susceptible subpopulation may be at a higher risk of developing an autoimmune disease without causing an overall increase in the disease incidence. Based on selected examples, this review highlights the difficulties in assessing this issue. We suggest that a potential link between vaccines and autoimmune diseases cannot be definitely ruled out and should be carefully explored during the development of new candidate vaccines.
Arthritis, Rheumatoid↗