The Japanese unit of major drugmaker Janssen Pharmaceuticals says 17 people have died after being injected with its drug to treat schizophrenia since it was launched in Japan last November.
The company, an affiliate of US-based healthcare giant Johnson and Johnson, advised medical workers in Japan to use the Paliperidone Palmitate medication with great care even though it was not know whether it had caused the deaths.
The drug, brand-named Xeplion, is estimated to have been used by 10,700 people since it was released in Japan on November 19, according to a notice posted on the Japanese unit's website and seen Wednesday.
The causes of the 17 deaths included cardiac infarction, pulmonary embolism and suffocation due to inhalation of vomit.
In many cases the deaths occurred about 40 days after injections of the drug.
The notice advised doctors to "fully understand that the substance remains in the body for at least four months after being injected" and to stay alert for any side-effects.
It also asked them to refrain from using the medicine with other anti-psychotic drugs because the "effectiveness and safety" of such a combined application had not been established.
The use of Xeplion has been approved in 78 countries and areas of the world as of June 2013, the company has said.