ATLANTA — Federal prosecutors say an Alabama man who imported a Chinese drug sold as a Viagra substitute has been charged with intentionally defrauding and misleading consumers. They say the drug sold as Zhen Gong Fu fails to list a potentially dangerous ingredient on its label.

Nabil Chagri allegedly distributed Zhen Gong Fu to gas stations. Laboratory analysis showed the drug contains sildenafil, which can provoke dangerous drops in blood pressure, particularly for men taking nitrates for heart disease or diabetes.

Chagri, 38, of Hoover, Alabama, has pleaded not guilty. His federal public defenders in Birmingham didn't immediately return requests for comment on Tuesday.

The U.S. Food and Drug Administration has warned consumers not to buy or use Zhen Gong Fu because of its potentially harmful effects.