CHICAGO — The American Medical Association called Tuesday for a ban on consumer advertising for prescription drugs and medical devices, saying such marketing could be driving demand for unnecessary expensive treatments.

The policy was adopted by physicians at an AMA meeting in Atlanta.

The AMA move follows stands by the World Health Organization, the National Center for Health Research and other groups, saying such advertising may pressure doctors to prescribe particular medications that may be less effective and more expensive and risky.

The United States and New Zealand are the only countries that allow direct-to-consumer prescription drug advertising.

According to Nielsen, drugmakers spent nearly $20 billion over the past five years to advertise drugs to consumers. The biggest share last year went to television ($3.2 billion), then magazines ($1.2 billion), newspapers ($127 million), radio ($26 million) and billboards ($4 million).

The top 10 advertised prescription drugs are for treating erectile dysfunction, arthritis, mental health issues and stroke prevention.