Levamisole is a medication available for treatment of parasitic worm infections and certain cancers. Due to the risk of potentially serious side effects, it has been withdrawn from the market in several nations, including Canada and the United States. In regions where it is not available, there are alternatives a doctor can use to provide patients with appropriate treatments. It may also be available for veterinary use only in regions where it is not available for humans.
This drug acts as an anthelmintic, effective against parasitic worms in the digestive tract. Veterinary uses of the drug are primarily focused on its applications as a dewormer. It can treat a variety of worm infections in many different species. The drug helps the body effectively eliminate parasites from the gut. In cancer treatment, levamisole appears to be an effective antineoplastic agent and can inhibit the growth of tumors, particularly in combination therapy with other medications.
There are three significant risks with this medication. The first is a chance of an allergic reaction that may lead to skin rash, difficulty breathing, and low blood pressure in some patients. Patients can also develop bone marrow suppression and decreased immune function while taking levamisole, and will be less able to fight off infections. The drug also appears to depress the central nervous system and can cause neurological complications.
Less serious side effects can include nausea and dry skin. These should resolve when the patient stops taking the medication. Patients who notice symptoms like tremors, lip smacking, and confusion should talk to their doctors, as these can be signs that the medication is active in the central nervous system. It is also important to be careful around potential sources of infection while taking levamisole, as it is easier to get sick and harder to combat the infection effectively.
Preexisting liver, kidney, or seizure disorders are contraindications for the use of this medication. The safety of levamisole in pregnant women is not known. Pregnant patients should discuss the risks and benefits with their doctors before starting treatment. If they do experience pregnancy complications, including birth defects, it is important to report them. Data from patients provides regulators with information they use to determine what kinds of warnings to issue with a medication. It can result in a decision to pull a drug from the market or issue a black box warning alerting patients to the fact that the medication is dangerous, but beneficial enough to remain on the market.