The novel the series is based on was seized by court order on February 2018, only to rocket to the top of Amazon's bestsellers list before the seizure was enforced. Antena 3 took advantage of the controversy to set an early premiere, since the series was not affected by the order, which eventually turned into the full series release. The seizure order was lifted in June 2018, more than a month after the series finale aired.
Carmen Avendaño is a real person. Jaime and Abel, two of her five sons, struggled with heroin addiction in the early 1980s. Sito Miñanco was involved in the early smuggling of Colombian cocaine and their colleagues also smuggled hashish into Spain, but they weren't involved in the heroin trade.
The word "Farina" is the Galiciam word for "flour". In Spanish word is "harina". Once the action takes place in Galicia, one of the regions where that language is widely spoken, this title makes sense.