You don't actually have statistics to back up your claim, do you? I'm assuming you don't simply because Singapore's number of heroin addicts has been rising since the mid 80s.
As far as I'm concerned, Singapore's "solution" could be 100% efficacious and I'd still find it counter to the principles of individual liberty. Furthermore, anyone who would back such a penalty for drug use, and I know that you don't, is a numbskull.