Allergan Inc said on Tuesday that U.S. health regulators will require more information before approving its Botox anti-wrinkle drug as a treatment for upper limb spasticity in stroke victims.

Allergan said the U.S. Food and Drug Administration has not requested further clinical studies, which could have delayed approval by years.

The company has said future revenue from therapeutic uses for Botox could eventually rival cosmetic sales, which exceed $1 billion a year. It is also counting on neurology uses for Botox to help shore up cosmetic sales that have been hit hard by the recession.

Allergan said the FDA indicated it must first review the company's proposed Risk Evaluation and Mitigation Strategy for the medicine before approving it for the movement disorder common to stroke sufferers. Botox and a competing drug also derived from botulinum toxin are required to carry a strong safety warning for non-cosmetic uses.

The FDA has asked for additional documentation and analysis of one of the Botox clinical studies included in the approval application, the company said. Allergan said it believes it can satisfy those conditions in about 60 to 90 days.

The agency has also proposed certain label revisions, including one that could broaden Botox use to upper limb spasticity regardless of underlying cause, the company said.