Cocaine (benzoylecgonine methyl ester) is extracted from the leaves of the South American coca bush (Erythroxylon coca) and belongs to the group of stimulants. 

In 2020, 685 samples declared as cocaine were handed in for analysis at the Drug Information Centre (DIZ) in Zurich. In a mobile drug checking carried out in the city of Zurich in 2020, six samples declared as cocaine were handed in and analysed. The results published here are not representative for the entire substance market of the city of Zurich. 

Risk assessment

In addition to the known side effects and the great psychological dependence potential of cocaine, the frequent occurrence of pharmacologically active extender substances, especially for regular users, means an additional health risk that is difficult to assess. These are rarely acute side effects, but rather long-term effects. The evaluation shows that even samples with a high cocaine content often contained pharmacologically active extenders. Apart from the pharmacologically active extender, the strongly fluctuating cocaine content is an often underestimated consumption risk. The higher the cocaine content, the greater the risk of overdose. High-dose cocaine can put a heavy strain on the cardiovascular system and, under certain circumstances and physical conditions, trigger a heart attack or stroke. Information and recommendations for low-risk use can be found under Cocaine Safer Use. 

Cocaine content

In 2020, the average cocaine content of the samples analysed at the DIZ and at the mobile drug checkings was 80 % cocaine*HCl. Compared to the previous year, there was hardly any change in the average active substance content, with a decrease of 0.2 %. The cocaine content of the samples analysed varied greatly and ranged from 1.6 % to 98.2 %. 

Cocaine content in %, 2011 - 2020, grouped (n=5'801) 

Pharmacologically active extender 

Cocaine is often a mixture of cocaine and one or more extenders. Some of these extenders are not pharmacologically active (e.g. lactose, starch, cellulose) and have no additional effects on health. However, the extenders are often chosen in such a way that a higher cocaine content is simulated and an effect enhancement and/or prolongation is induced. 

In 2020, 34.9 % (+3.4 %) of all cocaine samples that were handed in for analysis at the DIZ and at the mobile drug checkings were laced with at least one pharmacologically active substance. Levamisole was again the most frequently added substance (29.2 % of the samples). Other extenders were local anaesthetics (4.2 %), caffeine (3.8 %) and phenacetin (3 %). 

Most frequent extender in cocaine samples 2011 - 2020, in % (n=5'801) 

In the following, the pharmacologically active extenders analysed in cocaine samples in 2020 and their risks and effects are described. 


Levamisole is nowadays used in veterinary medicine against worm infestation. It was originally used in humans as an agent against threadworms (anthelmintic), but has not been used in human medicine since 2004 due to undesirable drug effects. Common acute side effects are vomiting and diarrhoea. Digestion can still be disturbed the following day. In addition, allergic reactions (shortness of breath, skin rashes, swelling of the lips, tongue or face), disturbances of the nervous system (numbness up to unconsciousness, severe fatigue) and speech problems may occur. 

The most dangerous side effects of levamisole are aplastic anaemia, agranulocytosis and vasculitis. Aplastic anaemia leads to a greatly reduced defence against serious infections (immunodeficiency) due to a lack of white blood cells. Agranulocytosis is a severe reduction in granulocytes, a subgroup of white blood cells. The disease begins unspecifically with a disturbance of the general condition and fever. Later, mucosal ulcers, skin necrosis and localised lymphomas (tumours of the lymphatic tissue) appear. Vasculitis leads to the death (necrosis) of skin areas due to the occlusion of small blood vessels. 

A study suggests that there is an additional danger from the degradation of levamisole to aminorex (amphetamine-like substance) in the human body. Aminorex had to be withdrawn from the market as an appetite suppressant because it leads to pulmonary hypertension (= life-threatening pulmonary hypertension). This risk accumulates with repeated use of Aminorex. Pulmonary hypertension does not occur acutely during use, but may only manifest itself after several months in the form of increasingly impaired physical performance, circulatory disorders and fatigue. Symptoms such as chills, infections in the respiratory tract, anal region, throat, etc. may be associated with the use of levamisole. These must be accompanied by a doctor and treated with antibiotics. 

Two studies by the University of Zurich have also shown that cognitive performance decreases in people who have regularly used cocaine with levamisole. The areas examined were attention, working memory, long-term memory and higher planning functions. It was found that the cortex of the middle frontal brain was clearly thinner in people who used levamisole regularly than in people who used less levamisole. This has a connection with the decrease in cognitive performance, since the planning function of humans is embedded in the middle frontal brain. 

Levamisole is probably used as an extender because of its effect-enhancing and effect-prolonging effect. 

In 2020, levamisole was analysed in 29.2 % of the cocaine samples (+5.1 %); on average, 13.8 % levamisole (+/-0 %) was contained in the samples. The highest levamisole content was 73.6 %. 


Phenacetin is an aminophenol derivative and has been used as a medicine to treat pain and reduce fever. Since phenacetin is harmful to the kidneys (phenacetin kidney) when consumed frequently in high doses, as well as increasing the risk of ureteral and bladder cancer, it has not been used medicinally in Europe since 1986. 

Phenacetin in high doses can cause excitement and euphoria, as well as slightly dazed and dulled perception, and is probably used as an extender for this reason. 

In 2020, phenacetin was analysed in 3.0 % of the cocaine samples (-1.4 %); on average, 17.6 % phenacetin (+2.9 %) was contained in the samples. The highest phenacetin content was 48.2 %. 

Local anaesthetics

Local anaesthetics are locally anaesthetising drugs. In 2020, procaine (14 samples), lidocaine (12 samples), benzocaine (2 samples) and tetracaine (1 sample) were analysed. In addition to side effects in the area of the central nervous system (e.g. agitation, seizures, coma), cardiac arrhythmia, drop in blood pressure and allergic reactions can also occur due to the use of local anaesthetics. Intravenous consumption of cocaine mixed with local anaesthetics is particularly dangerous. This can lead to paralysis of the central nervous system and delay or blockage of the cardiac excitation conduction system between the atria and the ventricles. Severe forms of this so-called AV block lead to a heartbeat that is too slow (bradycardia, bradyarrhythmia). In extreme cases, the ventricles can come to a complete standstill, which is life-threatening without medical treatment. Local anaesthetics are used as an extender due to their anaesthetic effect. Consumers falsely conclude from this that the cocaine is particularly pure when they have their tongues and gums tested for "quality control". 

In 2020, local anaesthetics were analysed in 4.2 % of cocaine samples (-0.7 %). 


Caffeine makes you awake, speeds up the heartbeat, temporarily increases mental performance and has an appetite-suppressing effect. In higher doses, from 300 mg (approx. 8 cups of coffee), caffeine also produces euphoria. At high doses, the following side effects are possible: sweating, fluttering of the heart, urinary urgency, cardiac arrhythmia, perceptual disturbances, tremors, nervousness and sleep disturbances. With permanent, regular use, there is a risk of dependence with physical symptoms. 

Caffeine is used as an extender because of its stimulating effect and effect-enhancing potential. 

In 2020, caffeine was analysed in 3.8 % of the cocaine samples (-1.3 %); on average, 10.3 % caffeine was contained in the samples (+3.3 %). The highest caffeine content was 40.3 %. 


Paracetamol is an analgesic and antipyretic drug from the group of non-opioid analgesics. Paracetamol does not cause any psychoactive effect even in high doses. An influence on the effect of cocaine can also be ruled out. 

Why paracetamol is added to cocaine cannot be said with certainty. 

In 2020, paracetamol was analysed in 2.2 % of the cocaine samples. (+1.2 %); on average, 17.4 % paracetamol was contained in the samples (+3.6 %). The highest paracetamol content was 84.7 %. 

Other pharmacologically active substances analysed 

In addition to the most common extenders described above, MDMA (5 samples), amphetamine (4 samples), methamphetamine (2 samples), ketamine (2 samples), benzoylecgonine (1 sample), trazodone (1 sample) and ethylnorhexedrone (1 sample) were analysed in individual cocaine samples as further pharmacologically active substances. In the case of MDMA, amphetamine, methamphetamine and ketamine, a mix-up or unintentional contamination (smear contamination in the minigrip) can probably be assumed. 


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