A U.S. advisory panel has recommended that drugs used by millions to treat attention deficit hyperactivity disorder (ADHD), should carry a warning of the risk of heart problems.
The advice comes despite the lack of clarity over whether the drugs do in fact contribute to sudden deaths, heart attacks and other complications.
The ADHD drugs include Ritalin and Adderall.
Dr. Peter Gross, the panel chairman and head of internal medicine at Hackensack University Medical Center in New Jersey, admits the data is at present only suggestive at this stage but doctors need to be made aware of that concern.
The Food and Drug Administration (FDA) will consider the panel's recommendation for a warning highlighted by a black box, the most serious type for prescription drugs.
It seems the committee voted 8-7 in favor of the warning, with one abstention.
The FDA reviewers say that each month, doctors write approximately 1 million prescriptions for ADHD drugs for adults and 2 million for children.
Several panel members were concerned because the ADHD drugs are amphetamines or chemically similar drugs, which are known to raise blood pressure, often a precursor to severe heart problems.
Dr. Steven Nissen, a panel member and cardiologist at the Cleveland Clinic, said many prescriptions were probably unnecessary and he hopes a new warning might deter some use.
Some panel members also voted to urge the drugs be dispensed with a patient-friendly guide that explained the risks.
According to FDA officials they normally reserved black-box warnings for risks clearly linked to a drug.
The FDA had asked only for input if cardiac problems were related to the widely used medicines.
An FDA report in April 2004 recorded 51 U.S. deaths among patients taking ADHD medicines.
Other reports describe high blood pressure, chest pain, heart attacks, strokes, irregular heart beats and fainting.
FDA officials emphasise that the drugs have important benefits for many children and adults with ADHD, in which trouble focusing and impulsive or hyperactive behaviour affects school, work or relationships.
They are concerned that overly strong warnings might discourage effective treatment.
Dr. Robert Temple, director of the FDA's medical policy office, has said they do not want to frighten people with data which is 'not very solid'.
Drug manufacturers are apparently considering the re-labelling of their products.