Linagliptin is an oral dipeptidyl peptidase-4 (DPP-4) inhibitor that increases endogenous incretin levels, enhancing glucose-dependent insulin secretion and suppressing glucagon release. Its predominantly non-renal elimination allows use across all stages of renal impairment without dose adjustment. Indicated for the treatment of type 2 diabetes mellitus in adults as monotherapy when metformin is inappropriate, and as combination therapy with metformin, sulphonylureas, or insulin when these agents alone fail to provide adequate glycaemic control.