Effects of propylthiouracil on intestinal transit time and symptoms in hyperthyroid patients

Gastrointestinal disturbances such as diarrhea and malabsorption with steatorrhea may show up in hyperthyroid patients. The aim of our study was to evaluate oro-caecal transit time (OCTT) and gastrointestinal symptoms in hyperthyroid patients before and after propylthiouracil administration.

Twenty hyperthyroid patients (15 Females and 5 Males, mean age 47 years) were studied. Eight of them had diarrhea and 10 steatorrhea. The control group was composed of 20 healthy volunteers (13 F and 7 M, mean age 49 yrs). OCTT and fecal fat excretion were measured before and after propylthiouracil administration (300 mg/day for 10 day and then 200 mg/day for 30 days).

Before the treatment in hyperthyroid patients had began the mean OCTT was significantly lower than in the control group (64 min. versus 107 min; p < 0.0001). After treatment mean OCTT became similar to the controls (p = ns); diarrhea disappeared in all affected patients and mean fecal fat excretion was reduced from 7.9 gr/24h to 3.4 gr/24h, with a statistically significantly difference (p < 0.0001).

The treatment with propylthiouracil induces the normalization of thyroid hormone status and consequently of OCTT with the disappearance of gastrointestinal symptoms, such as diarrhea and steatorrhea, with a better efficacy if compared to other drugs utilized in the treatment of hyperthyroidism.