The concern it raises is pharmacodynamic instead: both drugs independently reduce appetite and fluid intake, creating additive risk of dehydration, electrolyte imbalance, and acute kidney injury in vulnerable patients
You can get it as part of a Part C plan or as a standalone policy

Vildagliptin: peripheral oedema and nasopharyngitis Interactions Clinically significant drug interactions are described as follows: *Sitagliptin is metabolised primarily by CYP3A4, in severe renal impairment metabolism plays a more significant role in sitagliptin elimination, therefore potent CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir, clarithromycin) may increase sitagliptin plasma levels in severe renal impairment The blood glucose-lowering effects of DPP-4 inhibitors may also be enhanced or inhibited by other substances: References DPP-4 inhibitors | Prescribing information | Diabetes type 2 | CKS | NICE Sitagliptin 100 mg Film-coated Tablets Summary of Product Characteristics (SmPC) (emc) Onglyza 2.5mg film-coated tablets Summary of Product Characteristics (SmPC) (emc) Trajenta 5 mg film-coated tablets Summary of Product Characteristics (SmPC) (emc) Alogliptin 12.5 mg film-coated tablets Summary of Product Characteristics (SmPC) (emc)

Effects of Hericium erinaceus on amyloid (25-35) peptide-induced learning and memory deficits in mice
Many studies have demonstrated that GLP-1 suppresses feeding behaviors and modulates the spontaneous firing activities and/or glutamatergic or GABAergic neurotransmission in multiple brain regions