Drug Purity, Cutting Agents and Substitutes

Most of the drugs sold on the street aren’t exactly what they claim to be and are often mixed with cutting agents or substituted for similar-looking substances. Purity of drugs on the market is therefore in constant flux, hinging on factors such as drug policy, the price of chemical precursors, and the ever-morphing landscape of trafficking networks.

Additional substances make their way into street drugs at various points in the supply chain, either as impurities that occur as by-products of the manufacturing process or as cutting agents, which are deliberately added to dilute, bulk up the final product and improve profits. These adulterants often constitute a concerningly high proportion of the substance sold, sometimes reducing the purity of a drug to virtually zero.  Increasingly we also see sellers not even bothering with cutting the substances they sell, instead replacing less valuable substances for more expensive ones, occasionally which have significantly different effects, potentially significantly increasing harm to the consumer.

 

Here’s a look at some of the most common cutting agents in popular street drugs.

 

Cocaine

The cutting agents found in cocaine hydrochloride (powder cocaine) can be divided into pharmacologically inert fillers - or ‘diluents’ - and more nefarious ‘adulterants’, which are often added in lieu of cocaine with the intention of replicating or enhancing its effects.

 In the Americas, the majority of diluents found in cocaine consist of carbonates and bicarbonates, including those generally used in the food industry. In Europe, meanwhile, sugars like dextrose, fructose and glucose are the most common diluents. Largely harmless, these bulking agents are added to increase the weight of a drug without producing any narcotic effects.

Sadly, the same cannot be said of the adulterants found in cocaine. In 2015, 50 different dangerous cutting agents were detected in street cocaine samples in the UK, and the number may now be even higher.

Until fairly recently, a veterinary deworming medication known as levamisole was by far the most common adulterant found in cocaine worldwide. In 2015, the DEA estimated that 93 percent of all samples seized by US customs contained levamisole, while Dutch authorities found the substance in 70 percent of shipments the following year. By 2020, however, the use of this cutting agent had dropped considerably, with the medication appearing in less than 20 percent of the cocaine entering the US.

And that’s just as well, because levamisole causes nausea, diarrhoea and vomiting, while also contributing to pulmonary hypertension. Unsurprisingly, it’s been declared unsafe for humans.

Other common adulterants include caffeine - which is believed to potentiate the effects of cocaine - and local anesthetics such as lidocaine, benzocaine, procaine and norcocaine. Those in the latter category often disguise the reduction in cocaine purity as they mimic the drug’s numbing effect on the nose and mouth, but can trigger heart problems and seizures.

A painkiller called phenacetin, is also often found in cocaine. Considered unfit for human consumption, the drug damages the kidneys and may cause cancer.

Then there’s the heart medication diltiazem, which is regularly added to cocaine in order to enhance its effects but can cause major cardiovascular complications. Finally, the sedative antihistamine hydroxyzine often appears as a cocaine adulterant and has been linked to convulsions.

In 2022, an analysis of street drugs tested in Poland found levamisole in 38.6 percent of cocaine samples, while phenacetin appeared in 22.8 percent and caffeine was present in 21 percent.

In 2023, the average purity of cocaine samples submitted for drug testing across Europe was 45 percent.

 

MDMA

MDMA comes in both crystal and pill form, with the latter generally referred to as ecstasy. In 2021, only 54.8 percent of MDMA samples tested at festivals across the UK actually contained the compound, down from 92.8 percent in 2019. These findings underscore an alarming rise in the use of cutting agents in recent years.

In particular, the use of synthetic cathinones as adulterants in MDMA has skyrocketed. In 2023, these amphetamine-like compounds were detected in 44 percent of MDMA samples tested across Europe, making them by far the most common cutting agent for ecstasy.

The most well-known synthetic cathinone is mephedrone (4-MMC), which became popular in the UK and Europe in the late 2000s. Other examples commonly detected in MDMA include  4-CMC, 3-MMC and eutylone, all of which can cause heart problems, insomnia and psychosis.

Caffeine, meanwhile, was found in 21 percent of European MDMA samples in 2023, and was much more common in crystals than in ecstasy tablets. Hallucinogens were detected in ten percent, while amphetamine, ketamine and methamphetamine appeared in six, four and three percent of samples respectively.

The average purity of all MDMA crystals tested in Europe in 2023 was 44 percent, while ecstasy tablets contained an average of 115 milligrams of the compound.

 

Heroin

It is not uncommon for heroin to be tainted with other opioids such as codeine, morphine, or noscapine, all of which occur as opium-derived impurities. Before the drug hits the street, dealers regularly add both caffeine and paracetamol, which are by far the most common adulterants found in European heroin.

In the US, the anti-malaria medications quinine and quinidine are often added to heroin, with a sharp increase detected in 2022 when they occurred in more than 2,000 street drug samples. Another adulterant of concern in North America is the opioid fentanyl, which is around ten times more potent than heroin itself and has been linked to large numbers of accidental overdoses.

Equally alarming are a group of synthetic opioids called nitazines, which were invented as painkillers in the 1950s but were quickly declared too dangerous for human consumption. However, in 2019, the DEA reported that Chinese-manufactured nitazines had begun appearing in heroin and cocaine samples in the US. They later spread to Europe and have been implicated in numerous fatalities.

More recently, the veterinary sedative xylazine - also known as ‘tranq’ - has started showing up in heroin in the US, potentially contributing to yet more overdose deaths. In Europe, meanwhile, batches of heroin laced with synthetic cannabinoids have caused non-lethal poisonings in countries such as France and Lithuania.

Heroin samples tested across Europe in 2023 varied massively in purity, with the most adulterated containing just 9.3 percent of the actual drug while the least tainted contained 47 percent. The average purity was only 23 percent.

 

Other Drugs

It doesn’t happen often, but dangerous synthetic cannabinoids are sometimes sprayed onto cannabis or hashish products in order to enhance their effects. LSD, meanwhile, is occasionally substituted for other psychedelic drugs like 2CB, DOB or DOI.

Amphetamine - also known as speed - is another drug that is often contaminated with cutting agents. Samples tested across Europe in 2023 were 40 percent pure on average, with some batches containing as little as 8.3 percent of the actual drug.