MIDFIELD, Ala. (AP) _ An attorney for a man charged with rape says he will base an insanity defense on his client's use of Viagra, the popular anti-impotence medicine.

Will Wright, 42, is charged with raping and sodomizing the 19-year-old daughter of his live-in girlfriend.

Wright's lawyer, Charles Salvagio, said he intends to prove Wright is innocent due to a mental defect brought on by Viagra.

``I really hope that what comes out of this, in addition to justice for my client, is that doctors are made to take some precautions before prescribing the drug,'' Salvagio said.

In 1984, Wright pleaded guilty to a charge of sexual abuse. Salvagio claims that Wright should not have been prescribed the drug.

Arthur Green, deputy district attorney for Jefferson County, said he doubts Salvagio's tactic will work.

``I'd be very surprised if he came up with any medical testimony to satisfy the requirements,'' Green said.

Viagra, introduced by Pfizer Inc. in April 1998, was the first pill to treat impotence. It became an instant success, and was the fastest selling new drug in history.