Risk of Erythrocytosis during Concomitant Testosterone and SGLT2-Inhibitor Treatment: A Warning from Two Clinical Cases

Context Erythrocytosis is one of the most common side effects occurring during testosterone replacement therapy (TRT) in male hypogonadism. It is well known that all testosterone formulations may cause Hb and hematocrit increase, especially with short-Acting injectable formulations. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a new class of glucose-lowering agents that reduce hyperglycemia in patients with type 2 diabetes mellitus (T2DM) by inhibition of renal glucose reabsorption, leading to increased urinary glucose excretion. The co-occurrence of T2DM and hypogonadism is known to be increasingly frequent. However, to date, no adverse events with the concomitant use of TRT and SGLT2is are reported. Case Description We report two cases of erythrocytosis during testosterone treatment and SGLT2i in patients with hypogonadism and T2DM. Conclusion Considering that hypogonadism and T2DM are frequently associated, clinicians should carefully monitor the risk of occurrence of erythrocytosis when prescribing TRT and SGLT2i together.