Análise da absorção de levotiroxina em uso combinado com inibidores de bomba de prótons em pacientes com hipotireoidismo controlado.

Abstract

Proton pump inhibitors (PPI) are the most prescribed and without prescription class of drugs used for heartburn and gastroesophageal reflux disease (GERD). Among patients using levothyroxine (LT4),this is the most common drugs coadministration. We performed a randomized blind trial to access the effect of a standard PPI Omeprazole® in levothyroxine (LT4) absorption, varying its dosage and administration interval. A total of 63 patients, mean age 48,9 years the great majority females (89%), were allocated in 5 groups during 8 weeks (Placebo; LT4+PPI 20mg with 30 and 60min interval; LT4+PPI 40mg with 30 and 60min interval). Inclusion criteria included a stable dose of LT4 for one year and controlled parameters of thyroid function accessed before the use of PPI(serum FT4 and TSH). Patients in the groups who received PPI 20mg 30min, PPI 40mg 30 and 60min after the LT4 presented a statically significant increasing in TSH levels. Only the group LT4+40mg of PPI 30min after showed significant decrease in FT4(p=0,01). Most patients have not reached high enough values in need of adjustment in dosage of LT4, possibly a reflection of the trial short interval. Many studies failed in demonstrate the ideal interval between the use of these drugs and either if the dosage and this fasting time has any interference in LT4 absorption.In this trial, we concluded that the greater the dosage od PPI used, greater the absorption interference, and TSH levels increases more significantly the shorter the interval between the drugs administration.