Levamisole

Indications

Levamisole is primarily utilized as an adjuvant therapy in conjunction with fluorouracil following surgical resection for patients diagnosed with Dukes' stage C colon cancer. Additionally, it serves as a treatment option for malignant melanoma and cancers of the head and neck.

Pharmacodynamics

As a synthetic imidazothiazole derivative, Levamisole has been extensively employed for its anthelmintic properties in addressing worm infestations across both human and animal populations. Its mechanism of action as an anthelmintic likely involves targeting the nicotinergic acetylcholine receptor of nematodes. Furthermore, Levamisole functions as an immunomodulator; it acts as an immunostimulant, demonstrated by the increase in natural killer (NK) cells and activated T-cells in patients receiving this medication alongside 5-fluorouracil for the treatment of Stage III colon cancer.

Absorption

Levamisole is efficiently absorbed within approximately two hours when administered via the gastrointestinal tract, facilitating its prompt therapeutic action.

Metabolism

The metabolism of Levamisole occurs primarily in the liver, where it undergoes extensive biotransformation, resulting in the production of both active and inactive metabolites.

Mechanism of Action

Levamisole functions as an antiparasitic agent primarily through its agonistic interaction with L-subtype nicotinic acetylcholine receptors in the muscles of nematodes. This interaction impairs the nematode males' ability to control their reproductive muscles, consequently hindering their capacity for copulation. While the precise mechanism of Levamisole when used as an anticancer agent in conjunction with fluorouracil remains unidentified, its effects on the immune system are multifaceted. Levamisole is known to restore compromised immune functions rather than enhancing them beyond normal levels. It stimulates the formation of antibodies to various antigens, enhances T-cell responses by promoting T-cell activation and proliferation, and strengthens monocyte and macrophage functions, including phagocytosis and chemotaxis. Additionally, it increases neutrophil mobility, adherence, and chemotaxis.