LOS ANGELES An investigation into a hospital blunder has been launched after the newborn twins of actor Dennis Quaid and his wife Kimberly were reportedly given an overdose of a blood thinner.

The celebrity website TMZ.com said on Tuesday that the children, Thomas Boone and Zoe Grace, were given vials of heparin, used to prevent clotting, that were 1000 times stronger than what was prescribed.

The California state Department of Public Health was investigating reports of an incident involving newborn twins at Cedars-Sinai Medical Centre, department spokeswoman Suanne Buggy said.

Quaid, 53, is best known for roles in a string of hit films during the 1980s including Great Balls of Fire and Innerspace.

More recently he starred in the 2004 disaster film, The Day After Tomorrow.-AP