The 32-year-old, who is now clean, talked about his battle with drinking and recreational drugs which blighted the latter years of his career in an interview with BBC Radio Manchester due to be broadcast Thursday.
"I'd been on humongous benders. It wasn't just alcohol, it was cocaine and a mixture of other drugs.
"The cocaine just enabled me to drink more. From being so drunk, to then having some cocaine, and then being able to go another two or three days."
Whitley, who won 20 caps for Northern Ireland, was sent home from a squad in 2005 after breaking a curfew ahead of games against Azerbaijan and England to go drinking with team-mate Phil Mulryne.
But it was after moving from Sunderland to Cardiff in 2005 that he began to use Class A drugs.
"I remember Dave Jones (Cardiff manager at the time) at one point said to me 'Jeff, don't come in but we'll still pay you' (because of his drinking).
"I never took any other drug apart from alcohol and cigarettes when I was playing at the time. When Dave Jones said that to me I thought 'I've never tried cocaine, I'd give it a blast' and when I did I thought 'wow, this is what I'm missing'.
"I was hooked that quick. If you're an addict you can get hooked on computer games, texting, eating... it doesn't matter what it is.
"When it comes to class A drugs then you're in trouble."
When he was a child his family moved to Wrexham from Zambia. He played in the Wrexham Youth League before being taken on as a trainee at Manchester City.
He made his City debut in 1996 and went onto make 126 appearances at Maine Road, before mutually agreeing to leave the club after falling out of favour.
Whitley, who also represented Wrexham, Notts County, Stoke, Woodley Sports and Northwich in a 13-year career, confronted his addictions during a spell in the Sporting Chance Clinic and is now sober.
Source: AFP
Source: AFP