The woman was still unable to urinate and was sent home. Eight hours later, she was taken to a Burlingame, Calif., hospital after she demonstrated confusion, slurred speech and a unsteady gait.

The authors, Dr. David Klonoff and Dr. Andrew Jurow of Peninsula Hospital in Burlingame, said the woman's case points to a need to look into the effects drinking a lot of water has on drug test results.