As far as you can from concentrations of drug abusers as you can manage.
Drug abusers looking for a fix are fundamentally irrational in that they are slaves to their cravings. That makes them two legged Ebola vectors in a epidemic situation.
The easiest way to spot areas with a lot of drug abusers are electronic maps of high crime areas. There are a number of web sites and smart phone ‘Apps’ that will give you that information.
Good one... thanks.