A man has won $8 billion in punitive damages from Johnson & Johnson over claims that antipsychotic drugs gave him breasts without warning.

Nicholas Murray, 26 was given Risperdal from 2003 to 2008 to treat troubled sleeping, a result of autism, court documents show, but developed gynecomastia, a condition in which breast tissue usually found in women starts to grow in men.

Attorneys for Murray said Johnson & Johnson "knew that there was a significant risk of gynecomastia in male children" but "failed to warn healthcare providers."

Johnson & Johnson denies there is a "significant risk" of developing gynecomastia from Risperdal and has said it will appeal what it calls a "grossly disproportionate" penalty. The sum is expected to be lowered on appeal.

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A man has been awarded $8 billion in damages over claims he wasn't forewarned his antipsychotic medicine from Johnson & Johnson could cause him to develop breasts.

A jury at the Philadelphia Court of Common Pleas ruled on Tuesday that Nicholas Murray had been misled by the pharmaceutical giant and that the company should pay the huge damages as a result, Reuters reported.

Murray's attorneys, Tom Kline and Jason Itkin, said in a statement that Johnson & Johnson "valued profits over safety and profits over patients."

Murray, now 26, was prescribed the drug Risperdal as a minor by pediatricians from 2003 to 2008 because he had trouble sleeping, a result of "autism spectrum disorder," court documents show.

The drug is commonly prescribed to treat schizophrenia and bipolar disorder but is also used as a sleeping medicine.

Murray claimed taking Risperdal, produced by the Johnson & Johnson subsidiary Janssen, caused him to develop gynecomastia, a condition in which breast tissue usually found in women starts to grow in men.

The drug Risperdal, made by the Johnson & Johnson subsidiary Janssen. CBS News

Johnson & Johnson denied there was "any significant risk of gynecomastia from the use of Risperdal," the documents show.

Attorneys for Murray, however, argued there was evidence Johnson & Johnson "knew that there was a significant risk of gynecomastia in male children and adolescents but failed to warn healthcare providers."

Read more: The $572 million fine Johnson & Johnson has to pay for its role in the opioid epidemic is only 4% of its annual profit

Murray was awarded $680,000 compensation by a court in 2015, but those were not punitive damages on the company, The New York Times reported.

The medical multinational on Tuesday said the $8 billion figure was "grossly disproportionate with the initial compensatory award in this case" and that it was "confident it will be overturned."

Carl Tobias, a professor at the University of Richmond School of Law, told Reuters that the amount would almost certainly be reduced on appeal and that the jury was simply sending a message.

Risperdal was approved in 1993 by the US Food and Drug Administration for severe schizophrenia but was slowly prescribed for less serious conditions over time.

Legal claims have dogged Risperdal since it began circulating, with 13,000 lawsuits alleging it caused gynecomastia in boys, The Wall Street Journal reported Tuesday.