Oregon ? A pharmacy erroneously made a drug 10 times more potent than intended, which killed three people who received it at an Oregon clinic, the state medical examiner said Friday.

ApotheCure Inc., a drug compounding pharmacy company in Texas, said an employee made a weighing error in the creation of the drug colchicine.

The drug was only sent to the Center for Integrative Medicine in Portland, where three people received injections of the defective batch to treat back pain, ApotheCure said.

All three people, two from Portland and one from Yakima, Wash., died between the end of March and beginning of April from the toxic levels of the drug, officials said.

The Food and Drug Administration said it is investigating the case, but thinks the problem is contained.

Gary Osborn, a pharmacist and certified clinical nutritionist for ApotheCure, said the situation could have been contained earlier, but the clinic did not contact ApotheCure until nearly two weeks after the first death.