The sitagliptin and placebo groups had similar incidences of clinical adverse experiences (58.7% vs. 64.5%), drug-related adverse experiences (2.7% vs. 3.9%), and serious adverse experiences (1.3% vs. 3.9%), respectively. There were two clinical adverse experiences that were considered to be drug-related by the investigator with sitagliptin (gastritis and hypoesthesia) and three with placebo (exfoliative dermatitis with cellulitis, decreased blood pressure, and headache). There was one serious adverse experience with sitagliptin (overdose) that did not result in symptoms of hypoglycemia or the need for discontinuation, and three serious adverse experiences with placebo (myocardial infarction, overdose, and exfoliative dermatitis with cellulitis); of these, only the exfoliative dermatitis with cellulitis was considered by the investigator to be drug-related. There were no discontinuations due to clinical adverse experiences with sitagliptin and two with placebo (headache and exfoliative dermatitis). There were no reported occurrences of hypoglycemia in either treatment group. The sitagliptin group had a slightly higher incidence of gastrointestinal disorders (21.3% vs. 17.1%) and nervous system disorders (10.7% vs. 6.6%) compared with placebo; however, there were no particular adverse experiences in these categories that were notably different between the treatment groups.