Is it necessary to increase the dose of levothyroxine in patients with hypothyroidism who use omeprazole? É necessário aumentar a dose de levotiroxina em pacientes com hipotireoidismo que usam omeprazol?

ABSTRACT Objective: It is believed that gastric pH interferes in levothyroxine absorption. Omeprazole, which acts by blocking the secretion of gastric acid, might interfere in hypothyroidism control in patients using levothyroxine and this effect could be dose dependent. The present study aimed to investigate this possibility. Subjects and methods: Twenty-one patients with primary hypothyroidism who had been using a stabilized levothyroxine dosage for at least one year were selected and randomly assigned to take omeprazole at the dosage of 40 mg or 20 mg per day. The mean levels of thyroid-stimulating hormone (TSH) before and 3 months after omeprazole usage were compared in the entire sample and in each group. Results: Ten patients concluded the entire treatment protocol in the 20 mg group and nine patients in the 40 mg group. There was no significant difference in TSH levels before and 3 months after omeprazole treatment in the entire patient sample (median levels: 2.28 vs. 2.30 mU/L, respectively: p = 0.56). Analysis of each subgroup (20 and 40 mg) showed no significant variation in TSH levels before and 3 months after omeprazole treatment (median levels: 2.24 vs. 2.42 mU/L, p = 0.62, and 2.28 vs. 2.30 mU/L, p = 0.82, respectively). No significant difference in the absolute (p = 0.93) or relative (p = 0.87) delta were observed between the two subgroups. Conclusion: Omeprazole in the dosage of 20 or 40 mg/day does not interfere in a clinically relevant manner in the treatment of patients with hypothyroidism that was previously under control. Arq Bras Endocrinol Metab. 2014;58(7):731-6 Keywords Hypothyroidism; thyroxine; absorption; omeprazole; proton pump inhibitors RESUMO Objetivo: Acredita-se que o pH gástrico possa interferir na absorção de levotiroxina. O omeprazol, ao inibir a secreção de ácido gástrico, poderia interferir no controle do hipotireoidismo em pacientes em uso de levotiroxina de forma dose-dependente. O presente estudo tem como objetivo investigar essa hipótese. Sujeitos e métodos: Vinte e um pacientes em uso de dose estável de levotiroxina por no mínimo um ano foram incluídos e aleatoriamente selecionados para iniciar o uso de omeprazol na dose de 40 mg ou 20 mg por dia. Foram comparados os níveis médios de hormônio tireoestimulante (TSH) antes e 3 meses após o uso de omeprazol, na amostra total e em cada grupo. Resultados: Dez pacientes concluíram o protocolo de tratamento no grupo de 20 mg e nove, no grupo de 40 mg. Não houve diferença significativa nos níveis de TSH antes e 3 meses após terapia com omeprazol na amostra total de pacientes (média: 2,28 vs. 2,30 mU/L, respectivamente: p = 0,56). A análise de cada subgrupo (20 e 40 mg) não demonstrou variação significativa nos níveis de TSH antes e 3 meses após terapia com omeprazol (média: 2,24 vs. 2,42 mU/L, p = 0,62 e 2,28 vs. 2,30 um/L, p = 0,82, respectivamente). Não houve diferença significativa no delta absoluto (p = 0,93) ou relativo (p = 0,87) entre os dois subgrupos. Conclusão: Omeprazol na dose de 20 ou 40 mg/dia não interfere de forma clinicamente relevante no tratamento de pacientes com hipotireoidismo previamente bem controlados. Arq Bras Endocrinol Metab. 2014;58(7):731-6 Descritore

Stenosis of reverse great saphenous vein graft in infrainguinal arterial revascularization

Objective: The aim of this study was to evaluate the prevalence of hemodynamically significant infrainguinal bypasses stenosis using reverse great saphenous vein graft. Methods: From March of 2008 to March of 2009, 56 infrainguinal bypasses were performed with reverse great saphenous vein graft in 56 patients. On the 30th post-operative day, 32 out of 56 patients were submitted to vascular ultrasonography. The prevalence of significant graft stenosis was determined. In addition, the diagnosis of stenosis was related to the clinical and surgical characteristics of the patients. The variables analyzed at the moment of diagnosis were the localization of the graft stenosis, the risk factors associated with stenosis and the association of vascular ultrasonography findings with ankle-brachial pressure index (ABI). Results: The overall prevalence of significant graft stenosis was 48.4%. Out of the total number of observed stenosis, 19.4% were considered severe, and 29% mild or moderate. There was no significant association between the presence of significant stenosis and the following variables: gender, diabetes, hypertension, smoking, hipercholesterolemia, graft diameter, site of the distal anastomosis, and graft composition. There was a weak agreement between ABI and vascular ultrasonography in detecting stenosis in general (K = 0.30; CL95% 0.232 -0.473; p = 0.018). However, there was a substantial agreement in detecting severe stenosis (K = 0.75; CL95% 0.655 -0.811; p = 0.0001). Conclusion: There was a high prevalence of stenosis on the 30th post-operative day, mostly localized in the proximal half of the vein graft. There was no significant association of stenosis with clinical and surgical factors analyzed. ABI and vascular ultrasonography had weak agreement with the diagnosis of stenosis in general and an important agreement for the diagnosis of severe stenosis