Redmond O'Neal is getting extremely sick behind bars because the son of actor Ryan O'Neal and the late Farrah Fawcett is experiencing painful withdrawal from being off drugs, RadarOnline.com is exclusively reporting.

Redmond, 26, was formally charged Thursday with two felonies -- possession of heroin and possession of a firearm, which is illegal for a convicted felon. O'Neal is currently on felony probation stemming from a conviction of a prior heroin conviction in 2009.

Redmond O'Neal has formally pled not guilt to felony drug and firearms charges, RadarOnline.com is exclusively reporting.

O'Neal appeared in front of Judge Keith Schwartz at the LAX Airport Courthouse on Thursday. O'Neal's powerhouse attorney, Richard Pintal, tells RadarOnline.com that his client is being held without bail pending the next hearing.

"We received the discovery and the next hearing is set for August 24th," Pintal says. "We hope that we can achieve a favorable resolution of these matters that would involve additional further treatment for Mr. O'Neal. The judge denied bail, we respectfully implored the court so that Mr. O'Neal could receive assistance and treatment for the underlying causes of all of his criminal cases."