The US Food and Drug Administration has approved Zyprexa, Eli Lilly's drug, in tablet form, as a treatment for schizophrenia and bipolar disorder in teenagers, as has been confirmed by the company. The label has accordingly been updated, and highlights that doctors should keep in mind the side-effects, which include increased potential to gain weight, when prescribing it to teens.

Also to be considered are some other long-term side effects, also the recommended dosage for youngsters is lower than that for adults.

The new label informs of the need for a complete, comprehensive treatment in teens, while asserting that the drug should only be used as a "part of total treatment program for pediatric patients with schizophrenia and bipolar I disorder", which could include some psychological, educational and social programs.

The FDA has, however, indicated that an additional study is needed to study the link between antipsychotic drugs and weight gain.

Post the news of the approval, Lilly's shares gained 1.3% to trade at a new high of $37.88. So far this year, the company has gained 10%.