A man who died at a Brooklyn medical center while in NYPD custody following his arrest on drug charges was hospitalized after suffering apparent withdrawal symptoms, cops said Monday.

Reginald Newkirk was arrested Friday after officers spotted him holding a crack pipe in plain sight outside a Rockaway Parkway apartment building near Rutland Road in East Flatbush around 8:53 p.m. Friday, police said.

He was taken to Downstate Medical Center after falling ill around 6:45 a.m. the following day, but doctors cleared him about four hours later, and he was returned to the 67th Precinct, according to police.

Newkirk was hospitalized a second time, this time being taken to Kings County Hospital, after he began exhibiting withdrawal symptoms around 2:05 p.m. Saturday. He died there around 5 a.m. Sunday, police said

A spokesperson for the city’s Medical Examiner said Newkirk’s cause of death is pending further study.

Newkirk lived in the Ozone Park neighborhood of Queens, cops said.