Brazil sees spread of Amazon crack cocaine called oxi

A dirtier and cheaper variety of crack cocaine has taken hold in Brazil's Amazon towns and is now spreading to major cities.

Oxi (short for oxidado) or rust, has been known to users and authorities in the Amazon for almost two decades but over the last few years the police have noticed a significant rise in its use.

Researchers also say that even though oxi remains a drug of choice for the poor and homeless, it is making its way into the middle and upper classes.

Luiz Veiga spoke to BBC News about the work he does helping oxi addicts overcome their problem and his own history of substance abuse.