He told the High Court in Edinburgh that in January last year he was taking drugs and using a more addictive form of the Class A drug cocaine.
Advocate depute Alex Prentice KC asked him: “Did this drug take over your life at this time?”, to which he replied “yes”.
He was asked how much the drug was costing him in December 2023 and January 2024.
Mr El-Nakla, a gas and electrical engineer, told the court that he would spend £700 or £800 in a single day on the drug when he got paid, but after that it would cost him £10 to £20 a day.
It is alleged the trio put Mr Munro in an extreme state of fear for his safety by threatening and intimidating him.
Prosecutors say this caused him to flee through a high window, where he died from his injuries after falling to the ground.
Mr El-Nakla was called as a witness by the Crown and told the court that he had been clean of drugs for months.
He said in January 2024 he sourced crack cocaine from Stephen Stewart and would go to the Morgan Street flat to buy the drug.
He said on 9 January last year he went to the flat and got crack cocaine passed to him through the letterbox.