Unsuspecting cocaine users are placing themselves at significant risk of overdose, with research showing a massive variation in the purity of the drug sold on the streets.
And the cocaine is mixed with damaging adulterants, including a veterinary drug used to treat parasitic worm infections and painkillers that, if overused, have been linked to cancer.
An analysis by Forensic Science Ireland shows the overall purity of cocaine and heroin available to buy on the streets has increased in recent years.
Average Irish cocaine purity is below the European average, but the average purity of Irish heroin is significantly above.
The research shows a noticeable difference in the purity of cocaine sold in Dublin compared to the rest of the country, while the purity for heroin is marginally higher outside Dublin.
The analysis highlights the huge profits typically earned by cocaine traffickers — with the drug typically diluted by a factor of four after importation.
For heroin traffickers, the drug is diluted by a factor of roughly two.
The research shows that the average street purity of cocaine (packs between 0g and 25g) was 24% in 2015.
But the purity ranged from 1% to as high as 90% (around the highest purity).
Of the 18 samples tested, five were between 40% and just over 60% pure, while a further three were between 85% and 91% pure.
Tom Hannigan, director of chemical sciences at FSI, said the purity of street cocaine “jumps around” and that higher purities could have “adverse effects” on street buyers not suspecting high purity.
A previous study compiled by FSI showed that the average purity of street cocaine was 15% in 2010 and 19% in 2011 — indicating an increase since then (to 24%).
“Yes, it appears to have increased in purity, but it is relatively small and I would be reluctant to draw conclusions from that,” said Mr Hannigan.
He said adulterants are used to both “bulk up” and “potentiate” (increase the effects of) cocaine.
He said a veterinary drug called levamisole was found in 70% of cocaine samples. This medication is used to treat parasitic worm infections in animals.
Mr Hannigan said it is added to the cocaine in South America, noting that it is “known to have undesirable effects” and can affect a person’s immune system.
Other adulterants, benzocaine and lignocaine, are local anaesthetics commonly used by dentists in injections, and are not intended for oral use.
Another adulterant, phenacetin, is a painkiller that is banned in a number of countries as overuse has been linked to cancers.
“These adulterants are either not good for you or are not intended for human consumption,” said Mr Hannigan.
The purity of bulk cocaine seizures show purity rates of 60% or higher, with most between 70% and 90%.
Mr Hannigan said this cocaine can be diluted by a factor of four by the traffickers before it ends of the streets.
The average street purity of heroin has also risen in recent years, from 30% in 2011 to 34%, but still well below 2010 levels of 47%.
The purity of street doses can also vary, but no way as much as with cocaine, with most samples ranging between 20% and 45%.
Mr Hannigan said heroin purity has been “quite stable” over the years. Adulterants are typically caffeine and paracetamol. The purity is diluted on importation, often by a factor of around two. Bulk seizures have an average purity of 52%, but can be as high as 80%.
In relation to amphetamine, average purity was 9%, ranging from an average of 3% at street level to 28% at importation level, with caffeine the main adulterant.