Function of Levamisole 

Levamisole Hydrochloride (Levamisole HCl), is an anthelmintic (anti-worm) agent commonly used in large livestock such as cattle, pigs and sheep. In 1971 Levamisole  was found to have immunostimulatory properties and investigation into its use in humans began to expand.

Currently, Levamisole HCl is used in humans for diseases related to imbalances in the regulation of immune responses or deficiencies of the immune system, including autoimmune diseases, chronic and recurrent diseases, chronic infections and cancer. Levamisole has beneficial effects on host defense mechanisms and restores depressed immune responses in animals and humans.

Another interesting use of levamisole in humans is as a treatment for common warts (verruca vulgaris).

News of its anthelmintic efficacy and immune system benefits has been known among aquatic hobbyists for years.

As an added benefit, Levamisole boosts the immune competence of fish, humans, large animals, birds and some reptiles.

This article hopes to pull together what scientific information is available, a bunch of individual accounts, apply some common sense, and put together in one place a helpful guide to the use of Levamisole HCl for treating aquarium fish.

Application of Levamisole

1.Levamisole Hydrochloride (Levamisole HCl) is absorbed through the gut, can also be absorbed through the skin and is distributed throughout the body. Levamisole affects the neurotransmitters within the parasite and paralyzes the worm (spastic paralysis). The fish then passes the inactive worms. Good gravel vacuuming is advised after treatment to remove the paralyzed worms. Levamisole is not ovicidal, which means Levamisole will not affect eggs already present, but it will affect the larval stage of the worm. To ensure complete eradication of the parasite treat again after remaining eggs have hatched.

2.How does Levamisole HCl work as an immunomodulator

The mechanism of action for its immunostimulating effects is not well understood. Levamisole is believed that it restores cell-mediated immune function in peripheral T-lymphocytes and stimulates phagocytosis by monocytes. The drug appears to restore depressed immune function rather than to stimulate response to above-normal levels. There are multitudes of medical studies being done with its use in humans and animals, the goal being to attain understanding of its immunomodulating mechanism. 

The mechanism will be defined, with time. However, at the time of the writing of this article, there is no complete answer to this question. For us, Levamisole is enough to know that it does stimulate immune function in fish that are suffering due to parasites or disease.

3.How long will it stay in my fish and how do I get it out of my tank

Levamisole Hydrochloride (Levamisole HCl) is rapidly absorbed into the digestive system. Less than 6% of the medication is excreted unchanged in the urine and feces. Half-lives for several species have been recorded:

Cattle: 4 - 6 hours
Swine: 3.5 - 6.8 hours
Dogs: 1.8 - 4 hours