BACKGROUND: Tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factor (VEGF) receptor signalling are used in cancer therapy to inhibit angiogenesis. Unfortunately, VEGF inhibitors are known to induce severe hypertension in patients. This study aimed to elucidate the impact of the TKI lenvatinib on blood pressure, arterial stiffness, vascular reactivity, as well as cardiac function in a short-term murine model to shed light on potential contributors to cardiovascular (CV) toxicities associated with VEGF inhibition. METHODS: Male C57BL/6J mice were randomly divided into 2 cohorts, either treated for 4 days with lenvatinib 4 mg/kg/day or 40% hydroxypropyl β-cyclodextrin as control. In an additional study, mice were subjected to a 4-day treatment followed by a 4-day wash-out, with echocardiography and blood pressure measurements performed on day 2 and 7. Subsequently, ex vivo vascular reactivity of thoracic aortic segments was determined. RESULTS: Lenvatinib induced hypertension and arterial stiffness (i.e., increased pulse wave velocity), starting from day 2 of treatment. Further, left ventricular ejection fraction was reduced and the ventricle dilated upon treatment. Lenvatinib induced neither endothelial dysfunction nor impaired vascular smooth muscle cell reactivity to nitric oxide (NO). Interestingly, lenvatinib demonstrated a concentration-dependent increase in ATP-mediated relaxation. In addition, after the 4-day wash-out period, lenvatinib-treated mice did not show complete remission of hypertension. However, arterial stiffness, ATP-mediated relaxation and cardiac adaptation were recovered. CONCLUSION: This comprehensive investigation provides valuable insights into the interplay between VEGF inhibition, vascular function and cardiac outcomes, emphasising the need for nuanced understanding and further exploration of the differential effects of lenvatinib on the CV system. Additionally, the study proposes a synergistic formation between VEGF and ATP, indicating an enhanced response via P2Yx receptor signalling.