Wayne, 30, was rushed back to Cedars-Sinai hospital in Los Angeles but was not stabilized and was shaking uncontrollably.
He has been placed in an induced coma and is breathing through tubes. Sources at the hospital told TMZ that Wayne is still in critical condition but is stabilizing.
The prognosis is still uncertain, but his mother flew to Los Angeles last night in case she had to make any health decisions for him. Several other family members and friends in the rap community visited the hospital.
Doctors tested Wayne and found high amounts of codeine in his system, and sources suspect that he might have overdosed after being released from the hospital Tuesday. His stomach was pumped three times to rid his body of any remaining codeine.
The National Institutes of Health website says that codeine is usually combined with other medication, and that the outcome of codeine overdose depends on how well doctors are able to treat overdose of the other medications. The site lists seizures as a symptom of overdose, and says that even with successful treatment shock and brain damage may occur.
Representatives for the rapper told People he was "doing well," and despite being comatose, messages continue to be sent from his Twitter account.
I'm fine. Thank u— Lil Wayne WEEZY F (@LilTunechi) May 1, 2013