Clinical trial of risedronate in Japanese volunteers: a study on the effects of timing of dosing on absorption.

Because of its chemical structure, risedronate was thought to form a complex with divalent cations, e.g., Ca(2+), and to be likely to show changes in the efficiency of absorbance from the gastrointestinal tract according to the presence of food. Therefore, we conducted a crossover study using healthy Japanese adults to examine the effects of food intake on absorption after the oral administration of risedronate and to choose the best timing of regimen for risedronate. Using single doses of 5 mg risedronate, the following four dose times were investigated: (a) in the morning under a fasting condition without breakfast; (b) 30 min before breakfast; (c) 30 min after breakfast; and (d) 3 h after breakfast. The results showed that the C(max) and AUC(0-24) of the plasma risedronate concentrations and its cumulative urinary excretions decreased in the following order: fasting without breakfast >>30 min before breakfast >>3 h after breakfast >>30 min after breakfast. In other words, it was demonstrated that the absorption of risedronate decreases due to the effects of food. Several adverse events, whose causality with risedronate was unknown or possibly related, were observed, including headaches, diarrhea, increased CK-BB, and an increased urinary Beta(2)-microglobulin excretion rate, but none of these events was clinically significant, and none differed in frequency or severity from the events after a single oral administration. In consideration of the optimal practical timings required to administer risedronate for Japanese patients, therefore, it was found that ingesting the drug immediately after waking up in the morning, when the stomach is empty, was optimal, and that it was necessary to refrain from eating and drinking for at least 30 min after drug ingestion. Therefore, we determined that the optimal time for risedronate to be administered in Japanese patients is 30 min before breakfast.

RCT Entities:   Population Interventions Outcomes