State health officials are investigating whether five Rhode Island hospitals gave 2,000 patients the wrong form of their medications.
There are no reports of patients harmed by the mix-up.
The patients were prescribed timed-release medications but may have received the regular form of the medication instead. Those affected were all discharged from Newport Hospital, Miriam Hospital, Bradley Hospital, Rhode Island Hospital and Hasbro Children's Hospital in the last year.
Lifespan, the operator of the hospitals, says a software error is to blame. Lifespan has contacted 90 percent of the patients affected and says many already had corrected their prescriptions. Lifespan says all affected patients should be contacted by Thursday.
People who received out-patient or emergency room care were not affected by the computer error.