Effects of Phenytoin Sodium Injection into the Rat Tail Vein on Blood Vessels and Perivascular Tissues

Abstract

　Phlebitis may occur as a vascular injury caused by peripheral intravenous drug administration. However, the pathological basis for intervening in phlebitis remains unclear. In the present study, we examined the blood vessels and surrounding tissues in nine rats at 24 hours after phenytoin sodium injection, which may cause chemical phlebitis. As a result, no macroscopic inflammatory findings were observed. However, histological inflammatory findings, such as vascular endothelial injury, thrombus formation, and inflammatory cell infiltration, were obtained. Of note, the inflammatory cell infiltration was not localized solely to the blood vessel wall but was also present in the tissues surrounding the blood vessel in all rats. Thus, phlebitis was demonstrated to be an inflammation spreading to the tissues surrounding the blood vessel, possibly caused by drug leakage outside the blood vessel, with direct invasion into the blood vessel wall.