Introduction: Dipeptidyl peptidase (DPP)-4 inhibitors belong to one class of drugs that have been approved for treatment of type 2 diabetes (T2D) based on the glucose-lowering actions of the gastrointestinal hormone glucagon-like peptide (GLP)-1. Several different compounds are now available, and although their mechanism of action (inhibition of the catalytic activity of DPP-4) is the same, there are fundamental differences between them.

Areas covered: The authors discuss the differences between different DPP-4 inhibitors and review their therapeutic efficacy and key safety data. The literature covered includes original studies and meta-analyses identified in PubMed, recent abstracts presented at major diabetes scientific conferences, and clinical trials registered at ClinicalTrials.gov.

Expert opinion: Although there are some differences in the pharmacokinetic and pharmacodynamic profiles of the different DPP-4 inhibitors, all are small orally active compounds with broadly similar HbA1c-lowering efficacy. They improve glycaemic control in T2D, without increasing the risk of hypoglycaemia or causing weight gain. They can be used as monotherapy or in combination with other anti-diabetic therapies, including insulin, regardless of renal or hepatic function, and are efficacious across the spectrum of patients with T2D, including those with long-standing disease duration. DPP-4 inhibitors may also have beneficial effects beyond glycaemic control, although this remains to be demonstrated in purpose-designed clinical trials.