Movies - Drugs in A Clockwork Orange

[Carbine]

"There was me, that is Alex and my three droogs; that is Pete, Georgie and Dim. And we sat in the Korova Milk Bar trying to make up our rasoodocks what to do with the evening. The Korova Milk Bar sold Milk-Plus. That is milk plus vellocet or synthemesc or drencrom, which is what we were drinking. This would sharpen you up and make you ready for a bit of the old ultra-violence".

Any ideas what these drugs are? Someone i know thought synthemesc was synthetic mescaline, but was clueless about the other two.