Feb 15 (Reuters) - Culper Research has taken a short position on Acadia Pharmaceuticals' stock, it said on Thursday, sending the drugmaker's shares down as much as 8%.

Acadia's drug, trofinetide, to treat Rett syndrome, a genetic brain disorder, was launched in the U.S. last year under the brand name Daybue.

"Acadia has misrepresented Daybue's safety profile, and in turn, patent retention rates," Culper Research alleged in its report.

"The company now faces a wall of discontinuations due to insurance reauthorization requirements. Numerous insurance plans we reviewed require tangible proof of improvement on the drug," the report said.

Reuters could not immediately verify the short seller's allegations.

San Diego California-based Acadia, which licensed trofinetide from Australian drugmaker Neuron Pharmaceuticals , did not immediately respond to a request for comment.

The approval had allowed use of the drug in adult and pediatric patients two years of age and older, with a label warning of diarrhea and weight loss.

Culper the drug "will continue to decline over time as patients discontinue" treatment and the company "runs out of new patients to fill the gap" and estimates revenue from Daybue will be $316 million in 2024.

Analysts were expecting revenue of about $379 million for the drug in 2024, as per LSEG data.

Acadia has an antipsychotic drug sold under the brand name Nuplazid approved for patients with a type of Parkinson's disease.

The company's shares clawed back some lost ground and were last down 2.1%.

Short sellers make money by betting that the price of a security (such as a stock) will decrease.

(Reporting by Pratik Jain in Bengaluru; Editing by Shilpi Majumdar)