Pharmacology and mechanism of action Indications Side effects Contraindications and precautions Interactions Preparations References
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Pharmacology and mechanism of action Indications Side effects Contraindications and precautions Interactions Preparations References
Levamisole Structure
  • CAS No.14769-73-4
  • Chemical Name:Levamisole
  • CBNumber:CB3335709
  • Molecular Formula:C11H12N2S
  • Formula Weight:204.29
  • MOL File:14769-73-4.mol
Levamisole Property
Hazard and Precautionary Statements (GHS)
  • Symbol(GHS)
  • Signal word
  • Hazard statements
  • Precautionary statements

Levamisole Chemical Properties,Usage,Production

  • Pharmacology and mechanism of action Levamisole is the L-isomer of tetramisole and is more active than the racemic mixture. It was introduced in 1966 as a veterinary drug and a little later as a human anthelminthic drug against ascariasis. The drug has also shown to be effective against hookworms (Ancylostoma duodenale and Necator americanus), but results of reported studies are inconsistent [1]. The mechanism of action of levamisole in helminthiasis is through its stimulation of autonomic ganglia (nicotinic receptors) of the worms. On exposure to the drug, immature and adult worms show spastic contraction followed by tonic paralysis. This mechanism seems to be common to other anthelminthics such as pyrantel and bephenium hydroxynaphthoate [2]. In higher doses, levamisole acts as an immunostimulant. It restores depressed cell-mediated immune mechanisms in peripheral T-lymphocytes, but may have marginal effects in immunologically competent individuals [3]. The clinical implication of this effect in the treatment of helminthiasis is unknown.
  • Indications Monoinfections with Ascaris lumbricoides. In polyinfections, mebendazole is the drug of choice.
  • Side effects During the treatment of nematode infections the drug produces minor side effects including nausea, vomiting, abdominal pain and headache [4, 5]. During prolonged treatment as an immunomodulator in rheumatic arthritis and in cancer patients, serious side effects such as blood disorders (agranulocytosis, neutropenia and thrombocytopenia), kidney damage, influenza-like reactions, vasculitis, photosensitivity and allergy to the drug have been reported [6, 7].
  • Contraindications and precautions The drug should be avoided in patients allergic to the drug. Administration of levamisole may provoke a reaction similar to that seen after intake of alcohol together with disulfiram. During long-term treatment, patients with kidney damage or with blood disorders may experience exacerbation of their diseases.
  • Interactions Levamisole has been reported to displace the protein binding of rifampicin in vitro [8]. The clinical significance of this is as yet unknown.
  • Preparations Available as levamisole hydrochloride: 118 mg is equivalent to 100 mg base.
    • Ketrax® (Zeneca). Oral solution 40 mg base per 5 ml. Tablets 40 mg base.
    • Solaskil® (Rhône-Poulenc Rorer). Tablets 30 mg base, 150 mg base.
    • Ergamisol® (Lederle). Tablets 50 mg base.
    • Levamisol® (Janssen). Tablets 50 mg base.
  • References 1. Miller MJ (1980). Use of levamisole in parasitic infections. Drugs, 19, 122–130.
    2. van Wauwe J, Janssen PAJ (1991). On the biochemical mode of action of levamisole: an update. Int J Immunopharmacol, 13, 3–9.
    3. Renoux G (1980). The general immunopharmacology of levamisole. Drugs, 19, 89–99.
    4. Lionel ND, Mirando EH, Nanayakkara JC, Soysa PE (1969). Levamisole in the treatment of ascariasis in children. BMJ, 4, 340–341.
    5. Farid Z, Bassily S, Miner WF, Hassan A, Laughli LW (1977). Comparative single-dose treatment of hookworm and roundworm infections with levamisole, pyrantel and bephenium. J Trop Med Hyg, 80, 107–108.
    6. Chrisp P, McTavish D (1991). Levamisole/fluorouracil: A review of their pharmacology and adjuvant therapeutic use in colorectal cancer. Drugs & Aging, 14, 317–337.
    7. Amery WK, Butterworth BS (1983) The dosage regimen of levamisole in cancer: is it related to efficacy and safety Int J Immunopharmacol, 5, 1–9.
    8. Pérez-Gallardo L, Blanco ML, Soria H, Escanero JF (1992). Displacement of rifampicin bound to serum proteins by addition of levamisole. Biomed Pharmacother, 46, 173–174.
  • Originator Solaskil,Specia,France,1971
  • Uses Levamisole is used for initial and secondary immunodeficient conditions, autoimmune diseases, chronic and reoccurring infections, large intestine adenocarcinoma, helmintosis, and rheumatoid arthritis. Synonyms of this drug are decaris, tetramizole, and others.
    Levimasole is also a drug of choice for ascardiasis. Numerous investigations show that a single dose of levamisole heals from 90 to 100% of patients with ascardiasis, in particular those infected with A. duodenale. It is less effective against ancylostomiasis and strongyloidiasis. However, it is not effective against N. americanus. It seems likely that it has a gangliostimulating effect on parasite tissues in both the parasympathetic and sympathetic regions. Moreover, it is presumed that this drug has an immunomodulatory effect on the host organism. Synonyms of this drug are decaris, solacil, ergamisol, tramisol, immunol, and others.
  • Uses Biological response modifier.
  • Definition ChEBI: A 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b][1,3]thiazole that has S configuration. It is used (generally as the monohydrochloride salt) to treat parasitic worm infections in pigs, sheep and cattle and was formerly used in huma s as an adjuvant to chemotherapy for the treatment of various cancers. It is also widely used as an adulterant to coccaine.
  • Indications Levamisole (Ergamisol) is an antiparasitic drug that has been found to enhance T-cell function and cellular immunity. The drug improves survival of patients with resected colorectal cancers when combined with 5-fluorouracil; the mechanism of this interaction is not known. Levamisole does not have antitumor activity against established or metastatic cancer and has not been found useful in the adjuvant therapy of cancers other than colorectal cancer.
    The major adverse effects of levamisole are nausea and anorexia. Skin rashes, itching, flulike symptoms, and fevers also have been observed.
  • Indications Levamisole (Ergamisol) was originally developed as an antihelminthic drug. It potentiates the stimulatory effects of antigens, mitogens, lymphokines, and chemotactic factors on lymphocytes, granulocytes, and macrophages. It has been shown to increase T cell–mediated immunity.
    Levamisole has been used successfully in treating chronic infections. It also has been approved for use in combination with fluorouracil in the treatment of colorectal cancer.
  • Manufacturing Process To a stirred and refluxed suspension of 17 parts of 1,2-dibromoethane, 7.8 parts of sodium hydrogen carbonate and 50 parts of 2-propanol is added a mixture of 3.4 parts of dl-2-thio-1-phenyl-imidazolidine, 9 parts of a 20% potassium hydroxide solution in 40 parts of 2-propanol over a period of about 1 hour. After the addition is complete, the whole is stirred and refluxed for an additional 3 hours. The reaction mixture is evaporated. To the residue are added 18 parts of a 15% potassium hydroxide solution. The whole is extracted with toluene. The extract is dried and evaporated. The oily residue is dissolved in acetone and gaseous hydrogen chloride is introduced into the solution. The precipitated solid salt is filtered off and recrystallized from 2-propanol, yielding dl-2,3,5,6-tetrahydro-6-phenyl-imidazo[2,1-b]thiazole hydrochloride; melting point 264°C to 266°C.
    dl-6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole hydrochloride, 188 g (0.785 mol), is suspended in a mixture of 500 ml of water and 500 ml of methylene chloride. The suspension is stirred mechanically while 20% sodium hydroxide solution is added until the solution is basic. Ice is added from time to time to keep the temperature below the boiling point of the methylene chloride. The methylene chloride layer is separated, washed with water, dried over potassium carbonate and evaporated. The oily residue crystallizes with the evolution of the heat when poured into a beaker containing 100 ml of ether. The free base is washed with ether. The yield of dl-6-phenyl-2,3,5,6- tetrahydroimidazo[2,-b]thiazole is 151.4 g (0.746 mol), 94%. The product has a melting point of 90°C.
    A solution of 204.3 g (1 mol) of dl-6-phenyl-2,3,5,6-tetrahydroimidazo[2,1- b]thiazole and 232.3 g (1 mol) of d-10-camphorsulfonic acid in 1,750 ml of chloroform is allowed to crystallize overnight at -28°C. The solvate is recovered by filtration and washed with ice cold chloroform (400 ml). The solvate is dried (decomposed) under nitrogen 7 hours and then in air overnight. The yield of d(+)6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole d-10-camphorsulfonate is 202.5 g (0.464 mol) 92.8%, melting point 139°C to 140°C [α]D25+ 82.6 (C = 16, H2O).
    A solution of 150 g (0.344 mol) of d(+)6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole, d-10-camphorsulfonate in water is treated with 15.5 g (0.378 mol) of 98% sodium hydroxide and the liberated base extracted with chloroform. The chloroform solution is washed with water followed by sodium chloride solution and dried over magnesium sulfate. Evaporation of the solvent left 72.1 g of residue which crystallized shortly. The free base hereby obtained has a melting point of 60°C to 61.5°C and an optical rotation [α]D25+ 85.1 (C = 10, CHCl3).
    The free base d(+)6-phenyl-2,3,5.6-tetrahydroimidazo[2.1-b]thiazole is dissolved in 112 ml of acetone and 178 ml of isopropanolic hydrogen chloride is added all at once. The hydrochloride crystallizes at once. After cooling to below 0°C, the salt is recovered by filtration and washed with acetone. The product weighs 75.2 g (0.312 mol), 91%, from the camphorsulfonate, melting point 227°C to 227.5°C [α]D25+ 123.1 (C = 15, H2O).
  • brand name Ergamisol (Janssen).
  • Therapeutic Function Antiinflammatory
  • Antimicrobial activity Its principal activity is against Asc. lumbricoides and hookworms. Worms are paralyzed and passed out in the feces within a few hours.
  • Pharmaceutical Applications The l-isomer of tetramisole, available as the monohydrochloride. The d-isomer has no anthelmintic activity. It is very soluble in water and is stable in the dry state.
  • Mechanism of action Levamisole has immunomodulating activity. It is believed that it regulates cellular mechanisms of the immune system, and the mechanism of its action may be associated with activation and proliferative growth of T-lymphocytes, increased numbers of monocytes and activation of macrophages, and also with increased activity and hemotaxis of neutrophylic granulocytes. Levamisole also exhibits anthelmint action. It also increases the body’s overall resistivity and restores altered T-lymphocyte and phagocyte function. It can also fulfill an immunomodulatory function by strengthening the weak reaction of cellular immunity, weakening strong reaction, and having no effect on normal reaction.
  • Pharmacokinetics Oral absorption: c. 90%
    Cmax 150 mg oral: 0.5 mg/L after c. 2 h
    Plasma half-life: c. 4 h
    Volume of distribution: 100–120 L
    Levamisole is rapidly absorbed from the gut and extensively metabolized in the liver. It is excreted chiefly in the urine.
  • Clinical Use Ascariasis
    Hookworm infection
    Levamisole has been used in rheumatoid arthritis and some other conditions that are said to respond to its immunomodulatory activity.
  • Side effects Nausea, gastrointestinal upsets and very mild neurological problems have been reported.
  • Chemical Synthesis Levamisole, 2,3,5,6-tetrahydro-6-phenylimidazo[2,1-b]thiazole (31.1.4), is synthesized in various ways. One of them begins with α-bromoacetophenone, the reaction of which with 2-imino-1,3-thiazolidine gives 3-phenacyl-2-imino-1,3-thiazolidine (31.1.1). Reacting this product with acetic anhydride gives 3-phenacyl-2-acetylimino-1,3- thiazolidine (31.1.2). The ketone group in the resulting compound is reduced to an alcohol using sodium borohydride, and the resulting hydroxyl group in (31.1.3) is replaced with chlorine using thionyl chloride. Heating the product in acetic anhydride, the imidazole cycle closes, forming the product (31.1.4).

    A somewhat different approach was realized when using styrene oxide as the initial starting material. Reacting it with 2-imino-1,3-thiazolidine gives 3-(2-phenyl-2-hydroxyethyl)- 2-imino-1,3-thiazolidine (31.1.5), which is subsequently treated with thionyl chloride and then acetic anhydride to give the desired levamisole (31.1.4).
    Finally, the following scheme of making the product has been proposed using the same styrene oxide. Styrene oxide is reacted with aziridine, forming 2-aziridion-1- phenylethanol-1 (31.1.6). Treating this with potassium isothiocyanate or thiourea gives 3- (2-phenyl-2-hydroxyethyl)-2-amino-1,3-thiazolidine (31.1.5), and subsequent treatment with thionyl chloride (such as described above) and then with acetic anhydride gives the desired levamisole (31.1.4).
  • Veterinary Drugs and Treatments Depending on the product licensed, levamisole is indicated for the treatment of many nematodes in cattle, sheep and goats, swine, poultry. In sheep and cattle, levamisole has relatively good activity against abomasal nematodes, small intestinal nematodes (not particularly good against Strongyloides spp.), large intestinal nematodes (not Trichuris spp.), and lungworms. Adult forms of species that are usually covered by levamisole, include: Haemonchus spp., Trichostrongylus spp., Osteragia spp., Cooperia spp., Nematodirus spp., Bunostomum spp., Oesophagostomum spp., Chabertia spp., and Dictyocaulus vivapurus. Levamisole is less effective against the immature forms of these parasites, and is generally ineffective in cattle (but not sheep) against arrested larval forms. Resistance of parasites to levamisole is a growing concern.
    In swine, levamisole is indicated for the treatment of Ascaris suum, Oesophagostomum spp., Strongyloides, Stephanurus, and Metastrongylus.
    Levamisole has been used in dogs as a microfilaricide to treat Dirofilaria immitis infection in the past, but is rarely used today. It has also garnered some interest as an immunostimulant in the adjunctive therapy of various neoplasms.
    Because of its narrow margin for safety and limited efficacy against many equine parasites, levamisole is not generally used in horses as an antiparasitic agent. It has been tried as an immune stimulant, however.
Levamisole Preparation Products And Raw materials
Raw materials
Preparation Products
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