Heart failure NYHA classification III-IV. Pituitary or adrenal insufficiency, poor nutritional state, starvation, irregular food intake or debilitating condition, intensive exercise or excessive alcohol intake. Patients taking medication that may enhance blood glucose lowering effect of teneligliptin (β-blockers, MAOIs) or attenuate blood glucose lowering effect of teneligliptin (steroids, thyroid hormones). History of bowel obstruction or abdominal surgery. Concomitant use w/ sulfonylureas or insulin. Patients who are prone to QT prolongation, w/ existing or w/ history of arrhythmia, bradycardia, heart failure, low serum K, Torsades de pointes, patients using antiarrhythmic drugs (Class IA & III). Severe hepatic impairment. Pregnancy & lactation.