Contrast media (CM) given orally for roentgen examination of the upper
gastrointestinal tract may inadvertently enter the lungs. The present
paper describes the local effects on the lungs of rats after a single
intratracheal instillation of the nonionic, isoosmolar, dimeric CM io
dixanol and iotrolan, and the ionic, hyperosmolar, monomeric CM diatri
zoate. Hydrochloric acid (HCl) and saline were included as positive an
d negative controls, respectively. The test compounds were given by in
tratracheal instillation to anesthetized rats at dose volumes of 0.5 m
l/kg b.w. The animals were killed 6 hours, 24 hours or 7 days after do
sing, and the trachea and lungs subjected to histopathological examina
tion. Acute signs of dyspnea were observed in 7 out of 15 animals that
received HCl. No clinical signs could be related to treatment with an
y of the CM. Histomorphological assessment of the respiratory tract di
d not reveal any CM-related adverse effects, whereas animals treated w
ith HCl showed marked histopathological changes. The results indicate
that accidental exposure of the respiratory system to iodixanol, iotro
lan or diatrizoate is unlikely to cause any significant tissue damage
or lead to respiratory complications.