Relationship between Adverse Gastric Reactions and the Timing of Enteric-Coated Aspirin Administration.

Objective: This study aimed to elucidate the association between the adverse gastric effects of enteric-coated aspirin and the timing of its administration.

Methods: The study population comprised 572 patients (age range 45-84 years) admitted to Huaiyin Hospital between August 2012 and October 2014. Patients were administered a 100 mg enteric-coated aspirin tablet once daily: before a meal (30 min before a meal), during a meal, after a meal (30 min after a meal), or before sleep, and all patients were followed up for 6-9 months to observe for adverse gastric reactions and other side effects. Gastroscopy was performed if indicated by the patient's condition after obtaining due consent. In addition, release tests for an enteric-coated aspirin tablet were conducted using the chromatography method.

Results: Enteric-coated aspirin tablets released completely, with a release rate of >99 % under 20-120 min at pH > 5.5. Furthermore, the number of patients with recurring adverse stomach reactions was significantly lower in the before-meal and before-sleep groups than that observed in the during-meal and after-meal groups (p < 0.05). No significant between-group differences were observed with respect to damage to other organs. Similarly, the number of patients with gastric lesions was significantly lower in the before-meal and before-sleep groups than that observed in the during-meal and after-meal groups (p < 0.05).

Conclusions: The optimal time for once-daily administration of low-dose enteric-coated aspirin tablets was before a meal or before sleep owing to the increase in pH level during and after meals.