Navegando por Autor "SCHALCHER, Taysa Ribeiro"

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Acesso aberto (Open Access)
Clinical applications and methemoglobinemia induced by dapsone
(2014-10) OLIVEIRA, Fábio Rodrigues de; PESSÔA, Mariely Cristine Amador; ALBUQUERQUE, Rosyana de Fatima Vieira de; SCHALCHER, Taysa Ribeiro; MONTEIRO, Marta Chagas
Dapsone is a synthetic sulfone that is used as an antibiotic in humans and animals to prevent and treat diseases including leprosy, tuberculosis, malaria, and Pneumocystis carinii pneumonia and Toxoplasma gondii encephalitis in acquired immune deficiency syndrome (AIDS) patients as well as in anti-inflammatory conditions, such as dermatitis herpetiformis. However, this drug is also associated with several adverse effects, including dose-related hemolysis, methemoglobinemia, psychosis, peripheral neuropathy, agranulocytosis, aplastic anemia, hypersensitivity syndrome, sulfone syndrome, and others. Of these effects, methemoglobinemia is the most common side effect of dapsone, which leads to functional anemia and cellular hypoxia with symptoms of cyanosis, headache, fatigue, tachycardia, weakness, and dizziness. Thus, this review summarizes relevant information on the structure, mechanism of action, clinical indication, and adverse reactions of dapsone.
Acesso aberto (Open Access)
Efeito da dapsona na geração de estresse oxidativo em pacientes com hanseníase em uso de poliquimioterapia
(Universidade Federal do Pará, 2011) SCHALCHER, Taysa Ribeiro; VIEIRA, José Luiz Fernandes; http://lattes.cnpq.br/2739079559531098; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
Inflammation caused by Mycobacterium leprae infection and drugs with oxidative properties such as dapsone, are risk factors to induce the oxidative stress in leprosy patients. This study aims to determine plasma concentrations of dapsone in leprosy patients in use of multidrug therapy (MDT), correlating the development of oxidative stress. For the study, healthy individuals and leprosy patients were selected, followed before (D0) and after the third MDT-supervised dose (D3). The plasma concentrations of dapsone in patients under treatment (D3) were evaluated by high performance liquid chromatography. The oxidative stress was performed by methemoglobin (MetHb) and Heinz bodies determination, concentrations of reduced glutathione (GSH), nitric oxide (NO), malondialdehyde (MDA), total antioxidant capacity (TEAC) and enzymatic activity of catalase (CAT), superoxide dismutase (SOD) in blood. In the study were obtained 23 samples from leprosy patients in D0 and 13 in D3; and 20 healthy and without leprosy subjects. In patients before treatment (D0) were observed increase of NO (D0 = 18.91 ± 2.39, control = 6.86 ± 1.79mM) and significant reduction of the activity of SOD enzyme (D0 = 69.88 ± 12.26, control = 138.42 ± 14.99 nmol/mL). In MDT-treated patients (D3), the dapsone concentration in plasma was of 0,552 ± 0,037 μg / mL, and they showed Heinz bodies presence and significant increase in the MetHb percentage (D3 = 3.29 ± 0.74, control = 0051 ± 0.66%). In this patients also were observed increase of the GSH levels (D3=7.01 ± 1.9; control =3.33 ± 1.9 μg/mL) and decrease of the CAT activity (D3 = 10.29 ± 02.02, control = 19:52 2:48 ± U / g protein). However, MDA levels in D0 and D3 patients didn’t show changed, while TEAC levels, in this patients, significantly increased (D0 = 2.90 ± 0.42; D3 = 3.04 ± 0:52, control = 1.42 ± 0.18 μmol / mL). These data suggest that the MDT is mainly cause for oxidative stress, because it induced the generation of oxidative damage identified by Heinz bodies’ presence and increase in the MetHb percent.