Two drivers — one of them suspected of being under the influence of drugs — died after a crash Friday afternoon in Northampton, Southampton Town police said.

Brandon McKee, 24, of Center Moriches crossed the double-yellow lines on northbound Lake Avenue in his Toyota Scion and sideswiped a southbound GMC sport-utility vehicle, before slamming head-on into a Nissan Altima driven by Courtney Pivirotto, 26, of Eastport, police said.

The crash occurred shortly after 2:30 p.m., police said.

Pivirotto was pronounced dead at the scene. McKee was airlifted to Stony Brook University Hospital, where he died from his injuries Saturday morning, police said.

McKee had been charged with driving while under the influence of drugs, police said. The GMC’s two occupants were not injured.

Pivirotto worked as a personal trainer at Maximus Health + Fitness in Riverhead, friends said. She was a fitness guru with a contagious laugh who dedicated herself to helping people get in shape, they said.

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Rachel Ann Wells-Kirk said in an email that she met Pivirotto at Suffolk County Community College.

“Courtney was sweet, genuine and always striving to be better,” Wells-Kirk said. “She was successful, determined, and dedicated to make her life, and most importantly the lives of others, better.

“She left this world a better place, but too soon. In this horrible world we need people like Courtney, and it’s just a terrible loss for the world that she is gone, and in such a tragic way.”

Kandu Agbimson, a manager at Maximus Health, said Pivirotto was charged with opening the gym at 3:45 a.m. He said she was responsible and would listen to anyone’s concerns or problems.

He said she had earned a master’s degree, but was going back to school to become a dietitian.

An online GoFundMe account — Courtney Pivirotto Fund — has been established to accept donations for her family. The account showed $1,300 pledged as of Saturday night.

With Ellen Yan