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Structural formula
Structural formula of levamisole
Non-proprietary name Levamisole
other names

( S ) -6-phenyl-2,3,5,6-tetrahydro-imidazo [2,1- b ] [1,3] thiazole

Molecular formula
  • C 11 H 12 N 2 S levamisole
  • C 11 H 12 N 2 S HCl (levamisole hydrochloride)
Brief description

white solid (hydrochloride)

External identifiers / databases
CAS number
  • 14769-73-4 (levamisole)
  • 16595-80-5 (levamisole hydrochloride )
  • 32093-35-9 (levamisole phosphate)
EC number 238-836-5
ECHA InfoCard 100.035.290
PubChem 26879
DrugBank DB00848
Wikidata Q417097
Drug information
ATC code

P02 CE01 Q P52AE01

Drug class


Mechanism of action

Acetylcholine mimetic

Molar mass 204.29 g mol −1
Melting point
  • 60-61.5 ° C
  • 227–229 ° C (hydrochloride)

good in water (210 mg ml −1 at 20 ° C)

safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
GHS labeling of hazardous substances
06 - Toxic or very toxic


H and P phrases H: 301
P: 301 + 310
Toxicological data

223 mg kg −1 ( LD 50mouseoral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Levamisole is a drug from the group of imidazothiazoles that is used as a remedy against roundworms ( anthelmintic ). In addition, it has a stimulating effect on the immune system and can be used for chronic infections and inflammations as well as malignant tumors . It is the levorotatory isomer of tetramisol and is used in medicine as hydrochloride or phosphate . Levamisole hydrochloride is a white to pale cream-colored, almost odorless, crystalline powder.

In immunohistological assays (for example APAAP ) it is added to the substrate in the last staining step to block unspecific endogenous alkaline phosphatases. It specifically blocks only the endogenous non-intestinal phosphatases, but not the alkaline phosphatase derived from calf intestine in the APAAP complex. On the one hand, this ensures the specificity of the staining and, on the other hand, prevents the non-specific staining of endogenous intestinal phosphatases.


Levamisole can be administered either orally , subcutaneously or intramuscularly . It is mainly metabolized in the liver and has a plasma half-life of 4.4 to 5.6 hours. It is 20 to 25 percent bound to proteins.

It acts primarily as an acetylcholine mimic with an effect on the nicotinic acetylcholine receptor of the parasites. It causes depolarization in the ganglia and motor end plates , and thus persistent spastic paralysis of the parasites. The worm-killing effect is dose-dependent and occurs after about one to three hours. Some roundworms such as Ostertagia spp. however, they are already resistant.

In addition to the anti-parasitic effect, the active ingredient also stimulates the immune system in small doses, which corresponds to that of thymopoietin (a hormone that has an effect on the thymus ). It causes an increase in the differentiation of the T lymphocytes and the activity of the differentiated T lymphocyte forms.

Side effects

The most common side effects are vomiting and diarrhea. In addition, persistent states of excitement as well as hypersalivation , pulmonary edema , shortness of breath and frequent urination and feces can occur. Agranulocytosis , which is often fatal, can occur in people who are carriers of the histocompatibility antigen HLA-B27 , which is why levamisole is not commercially available in Germany. The most dangerous side effects are the aplastic anemia and vasculitis , and also by the reduction of levamisole to Aminorex that pulmonary hypertension .

Extender in cocaine

The admixture of levamisole to cocaine is increasingly observed as an extender, which was found in approx. 70% of the samples in 2016 with an average proportion of 13.2%. In April 2011, more than 80% of all samples from the American drug control agency contained levamisole.

Trade names

Veterinary medicine: Belamisol , Chronomintic ad us. vet., Citarin-L , Concurat-L , Levovermax cutaneous , Nematovet , Nilverm nova , niratil pour on , Ripercol Drench , Levamicil , Vetamisol Spot-on

Web links

Individual evidence

  1. a b c data sheet levamisole at Acros, accessed on February 26, 2010.
  2. a b entry on levamisole. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
  3. a b data sheet Levamisol hydrochloride from Sigma-Aldrich , accessed on May 13, 2017 ( PDF ).
  4. External identifiers or database links for levamisole hydrochloride : CAS number: 16595-80-5, EC number: 240-654-6, ECHA InfoCard: 100.036.943 , PubChem : 27944 , ChemSpider : 25996 , Wikidata : Q27107205 .
  5. External identifiers or database links for levamisole phosphate : CAS number: 32093-35-9, EC number: 250-920-3, ECHA InfoCard: 100.046.276 , PubChem : 198119 , ChemSpider : 171476 , Wikidata : Q27278002 .
  6. JL Cordell, B. Falini et al. a .: Immunoenzymatic labeling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP complexes). In: The Journal of Histochemistry and Cytochemistry. Volume 32, Number 2, February 1984, pp. 219-229, PMID 6198355 .
  7. ^ Bernhard Manger: Checklist XXL Rheumatology. Thieme, 2005, ISBN 978-3-131-51683-1 , p. 130 ( limited preview in Google book search).
  8. HKu: Levamisole - Dangerous Extender in Cocaine. In: toxinfo.ch. Tox Info Suisse, August 22, 2016, accessed on November 11, 2016 .
  9. Cocaine Adulterated with Levamisole on the Rise .