A shortage of a versatile medicine used to treat immune disorders and other diseases has forced U.S. hospitals and infusion clinics to suspend treatment for many patients.

The medicine, immune globulin, contains antibodies harvested from plasma, a component of blood. The injected product helps people with compromised immune systems fight off infections, and treats certain muscle and nerve disorders. The drug’s shortage increases the risk of infection for patients and the amount of pain they are suffering, doctors say.