Lil Wayne -- Day 6 in Intensive Care at Hospital

Lil Wayne is still in rough shape ... and remains in the intensive care unit at an L.A. hospital 6 days after being admitted for seizures stemming from a suspected drug overdose ... TMZ has learned.

Sources tell us ... Wayne's condition has not improved enough to be moved out of the ICU ... and he continues to be monitored very closely by staff at L.A.'s Cedars-Sinai hospital.

We know Wayne has been surrounded by friends and family since he was admitted to the ICU this past Wednesday ... and we're told the mood around Wayne's bedside has been very serious.

Among Wayne's visitors -- Drake, Chris Paul, Nicki Minaj, Birdman and others.

TMZ broke the story ... Wayne's stomach was pumped at least 3 times after doctors suspected he had overdosed on the prescription drug codeine ... the main ingredient in "sizzurp."

Wayne has struggled with codeine for years -- and just a few months ago suggested he had quit using the powerful painkiller.