Deaths force GSK to add warning to attention deficit disorder drug

The US Food and Drug Administration has ordered GlaxoSmithKline to put a black-box warning on its Dexedrine drug for attention deficit hyperactivity disorder to alert doctors and patients to the risk of heart problems and psychotic behaviour.

The FDA said there had been reports of sudden death caused by stimulant treatment in children and adolescents with serious heart problems. The new labels will also alert patients to the risk that pre-existing psychotic disorders, such as bipolar illness, may be exacerbated. New psychiatric symptoms such as hallucinations can also emerge.

The FDA decided in May that all manufacturers of ADHD drugs should update their warnings about the risks they carry. This affects Novartis's Ritalin, Shire's Adderall XR, Eli Lilly's Strattera and Johnson & Johnson's Concerta.

GSK wrote a Dear Doctor letter advising US practitioners of the changes in the labelling of Dexedrine. The letter was published on the FDA's website on Monday. Dexedrine is one of GSK's oldest drugs, having been launched in 1952. The company said it had a 0.8 per cent share of the American ADHD market. "It's a really small part of our business," a spokeswoman said.

Ritalin also hit the market in the 1950s and is used by 8.4 million patients a year worldwide. "It is not one of our top 10 products," a Novartis spokeswoman said.

Its smaller rival, Shire, relies on Adderall for much of its growth. It captured a record 26 per cent of the American ADHD market last year, with sales of $730.8m (£387.5m).

Five million Americans use ADHD drugs, 3.3 million of them under 19. FDA reports describe a seven-year-old boy who after taking ADHD drugs thought he saw people coming into his house and stealing presents.