Actor Dennis Quaid and his wife, Kimberly, filed suit today against a manufacturer of the blood thinner heparin, saying the product's labeling and design contributed to an overdose of the drug given to their newborn twins last month.

The Quaids' babies, Thomas Boone and Zoe Grace, received 1,000 times the intended dosage of the blood thinner Nov. 18 at Cedars-Sinai Medical Center. Nurses mistakenly administered a dose with a concentration of 10,000 units per milliliter instead of 10 units per milliliter, the hospital has acknowledged. Heparin is used as a flush to prevent blood clots in intravenous lines.

In their suit, filed in the Circuit Court of Cook County, Ill., the Quaids contend that Baxter Healthcare Corp. failed to recall the 10,000-unit vials of heparin even though the firm knew that other infants had died as a result of similar medication errors. Three babies in Indiana died last year after nearly identical mistakes. The lawsuit also faults Baxter for using shades of blue as the prominent background color on the label of both the high concentration and the smaller one "when they knew that such packaging" could have caused fatal errors.