Nurses at a New Jersey hospital allegedly gave patients Benadryl to zonk them out and “lighten the workload,” a fellow nurse alleges in a new lawsuit.

Patricia Moran, of Wall, claims several night-shift co-workers in the adult psychiatric unit at Monmouth Medical Center in Long Branch secretly and “knowingly misused” the medicine to make patients drowsy or put them to sleep, according to court papers filed in New Jersey Superior Court Wednesday.

The nurses allegedly “deceptively” failed to note in patients’ charts that they had been given the antihistamine, she claims in the suit.

When Moran complained about the misconduct in March 2019, her boss allegedly launched an “immediate retaliatory campaign” to force her to quit or justify firing her, court papers allege.

Even though a supervisor sent out “instructions to stop” the practice, her boss allegedly gave Moran a “bogus” evaluation and transferred her to the children’s unit, for which she wasn’t properly trained, the suit charges.

Moran was later suspended for more than three months without pay and told she might be fired, she claims in the lawsuit.

Moran’s lawyer, Matthew Luber, told The Post the hospital “turned its back” on her and that its conduct was “egregious.”

“No employee deserves to be treated in such a manner, let alone someone who has dedicated more than 31 years at this particular hospital. Ms. Moran looks forward to her day in court,” Luber said via email.

A spokeswoman for RWJBarnabas Health, a health care network that owns the hospital, said the allegations in the lawsuit were false.

“Monmouth Medical Center is fully committed to providing a safe environment for our patients, visitors and staff. The hospital disagrees with the allegations and intends to vigorously defend itself against this complaint,” she told The Post.