May 20 (Reuters) - A Howard University scientist on

Monday sued the U.S. Food and Drug Administration for failing to

act on his six-year-old petition seeking a warning label for two

classes of common antidepressant drugs about the potential for

persistent sexual side effects.

In a complaint filed in Washington, D.C. federal court,

Antonei Csoka said the FDA has "unreasonably delayed issuing a

decision in light of the nature and extent of the public health

interests addressed in the petition."

Csoka was one of 22 scientists who filed the so-called

citizen petition with the FDA in May 2018, urging the agency to

require an update to warning labels of selective serotonin

reuptake inhibitors (SSRIs) and serotonin-norepinephrine

reuptake inhibitors (SNRIs).

Current warning labels for the drugs - which include Eli

Lilly's ( LLY ) Prozac, Viatris's ( VTRS ) Effexor and generic versions of them -

warn of sexual side effects during use. The petition said

research has showed that these side effects, including loss of

sexual function and pleasure, can persist after the drugs are

discontinued.

The FDA declined to comment on the lawsuit.

Csoka's lawsuit said that the FDA ran afoul of its own

regulations, which generally require a response to citizen

petitions within 180 days. It said that the agency issued an

interim response in November 2018 saying the petition required

further review, but has since not made a decision or taken any

actions requested in the petition.

European and Canadian regulators have since warned that

SSRIs and SNRIs can have persistent sexual side effects, it

said.

"The FDA needs to act in a timely way to inform the public

about the risks associated with use of these drugs," Michael

Kirkpatrick of Public Citizen Litigation Group, a lawyer for

Csoka, said in a statement. "The FDA's failure to act exposes

consumers to potentially life-long harm."

The case is Csoka v. Food and Drug Administration, U.S.

District Court for the District of Columbia, No. 1:24-cv-01486.

For Csoka: Michael Kirkpatrick and Nicolas Sansone of Public

Citizen Litigation Group

For FDA: not available

(Reporting By Brendan Pierson in New York)