May 11, 2006
Thyroxine Absorption is Impaired with H.
pylori and Gastritis
Patients
with impaired acid secretion require an increased dose of thyroxine,
suggesting that normal gastric acid secretion is necessary for effective
absorption of oral thyroxine, according to findings
in the latest issue of New England
Journal of Medicine.
Malabsorption of thyroxine has been described in patients
treated with drugs that modify an acidic environment. Investigators determined
whether there is an increased need for thyroxine with
euthyroid multinodular
goiter and impaired secretion of gastric acid by assessing the dose of thyroxine required to obtain a low level of thyrotropin in 248 patients with multinodular
goiter. Of these patients, 53 also had Helicobacter
pylori-related gastritis and 60 had atrophic gastritis of the body of the
stomach. Of these 53 patients, 31 had evidence of infection and 29 were without
such evidence. The reference group comprised 135 patients with multinodular goiter and no gastric disorders. In addition,
variation in the level of serum thyrotropin was
prospectively studied in 11 patients treated with thyroxine
before and after H. pylori infection.
The team also studied these levels both before and during treatment with omeprazole in 10 patients treated with thyroxine
who had gastroesophageal reflux.
The daily
requirement of thyroxine was higher in patients with H. pylori-related gastritis, atrophic
gastritis or both conditions. The researchers observed the occurrence of H. pylori infection in the 11 patients
treated with thyroxine led to an increase in the
level of serum thyrotropin. They noted that this
effect was nearly reversed on eradication of H. pylori infection. In a similar way, omeprazole
treatment was associated with an increase in the level of serum thyrotropin in all 10 patients treated with thyroxine. The team found that this effect was reversed by
an increase in the thyroxine dose by 37 percent. –
Newsfeed from GastroHep.com
New
England Journal of Medicine; 2006: 354(17):1787-95