For a time this year, a psychiatric hospital run by the state of Maryland didn't have enough injectable drugs for schizophrenia patients who refused to take pills. Doses of the most effective drug to boost blood pressure in patients at risk of dying from infection-related shock were low at Johns Hopkins Hospital. And some local pharmacists were having trouble filling prescriptions for attention deficit hyperactivity disorder. The drugs are among hundreds that have been in short supply at the nation's hospitals, and more recently, community pharmacies. Pharmacists, doctors and advocacy groups say countless patients are getting less effective or more costly substitutes as a result. Occasionally, they may be receiving inappropriate drugs or doses ? or no treatment at all. "Every month we review what's not available to us," said Pamela Lipsett, MD, a professor of surgery at Hopkins. "We get one [drug] back and lose another. And some diseases have only one drug. It's very frightening."