About 12% of drugs doctors prescribe are for uses other than those approved by regulators, a recent study found. So-called off-label prescribing significantly raises the rate of negative side effects, the research showed.

Doctors are free to prescribe medications off-label, and in some cases patients benefit from those prescriptions. Physicians may find that an off-label drug is more effective at treating a problem than medications specifically approved for that use. For example, amitriptyline, approved to treat depression, is often used off-label for migraines.

The study, published in the journal JAMA Internal Medicine in November, suggests doctors should take greater care in choosing when to use off-label drugs and to more closely monitor patients receiving them, said Chester Good, a physician with the Department of Veterans Affairs, VA Pittsburgh, who co-wrote an editorial accompanying the study.

Often Prescribed

Top five drugs used off-label without strong scientific evidence, according to a recent study.

• QUININE
  Off-label use: nocturnal leg pain
  Approved use: malaria (falciparum)
• GABAPENTIN
  Off-label use: bipolar disorder
  Approved use: seizure disorder
• QUETIPINE
  Off-label use: dementia, insomnia
  Approved use: bipolar disorder
• AMITRIPTYLINE
  Off-label use: irritable bowel syndrome, fibromyalgia
  Approved use: depression
• RISPERIDONE
  Off-label use: obsessive compulsive behavior, ADHD
  Approved use: schizophrenia, bipolar disorder

“I’m not saying that physicians shouldn’t be using drugs off-label, it happens all the time,” Dr. Good said. “But we need to be more circumspect when we do so. Indications should either be supported by some evidence or recommended in guidelines.”

Doctors often don’t know if the reason for prescribing a drug is off-label or on-label, studies have shown. They typically choose a drug based on other patients’ experiences with similar conditions or clinical guidelines from professional organizations, which sometimes include off-label use of a drug. Patients wanting to know if the drug they are getting is for an approved use should ask their doctor, some health experts suggest.

Other studies have found higher estimated rates of off-label drug use—perhaps as much as 20% of all prescriptions. The rate is greatest among patient groups that normally aren’t included in drug companies’ clinical trials, such as children, pregnant women and psychiatric patients, said William Lanier, a professor of anesthesiology at Mayo Clinic in Rochester, Minn. Cancer patients frequently get off-label drugs because medication approved to treat one type of tumor may be found useful in treating other types, according to the American Cancer Society.