The warning, in a two-page letter to physicians dated Aug. 22, is unusual in that Wyeth's Effexor currently isn't even approved or recommended for use in children. Drug makers usually issue such warnings, commonly known as "Dear Doctor" letters, only for severe risks associated with a treatment's approved uses, often at the urging of the Food and Drug Administration.

Wyeth's letter comes after similar questions swirled around GlaxoSmithKline PLC's (GSK, news) Paxil, one of the most commonly prescribed antidepressants. In June, U.K. regulators urged doctors not to prescribe Paxil to children because of data linking it to suicidal behavior in those under the age of 18. The Food and Drug Administration immediately echoed a similar warning. Glaxo hasn't yet sent its own letter to U.S. doctors, but it has to physicians in the U.K., Ireland and Canada.

In the letter, Wyeth told physicians that in recent clinical trials of children ages six to 17, Effexor did not demonstrate efficacy in treating anxiety or severe depression. In the unpublished studies of children and teenagers, researchers saw "increased reports of hostility and, especially in Major Depressive Disorder, suicide-related adverse events such as suicidal ideation and self-harm."

Wyeth declined to specify how many studies it has conducted of Effexor and children or how recent, only to say that the data are from several studies, some of them continuing. Wyeth spokesman Douglas Petkus said the company decided to notify doctors as a precaution, but said that it wasn't prompted to do so by Paxil-induced concern about antidepressant use in children.

Wall Street Journal Staff Reporters Vanessa Fuhrmans and Anna Wilde Mathews contributed to this article.

  Dow Jones Newswires
   09-03-03  0210ET