EXCLUSIVE
Soulja Boy tells TMZ ... he's "mad as hell" over Actavis' decision to cease all production of promethazine codeine -- saying it doesn't punish rappers -- it hurts the infirmed.
S.B. doesn't think Actavis' decision had anything to do with celebrities drinking it -- even though that's what the company said , adding, "Actavis is running away from money ... they could be selling out everywhere."
Soulja says he drinks Actavis on the road so he can sleep -- and he says there's nothing wrong with that ... so he's rallying his friends together in a petition drive.
Soulja adds, "As far as the lean goes, just know I been had the juice since 2011."
Wild guess ... that testimonial won't help his cause.
