Although some people refer to L-asparaginase as an anti-cancer drug, it is actually an enzyme extracted from bacteria rather than a synthesized chemotherapeutic drug.1 Enzymes are proteins which catalyze or speed up biochemical reactions in body. This particular enzyme is useful as an antitumor agent because it catalyzes the breakdown of L-asparagine, a nutrient that is absolutely required for cancer cell division. The rationale behind using L-asparaginase is based on the finding that tumor cells have an unusually high requirement for L-asparagine and cannot produce enough of it; normal cells need less and are fully capable of producing this essential nutrient. Without L-asparagine, tumor cells will starve.2
L-asparaginase is most commonly used to treat lymphoma or acute lymphocytic leukemia (ALL). It can also be used to reduce growth of mast cell tumors.
This drug does not usually cause side effects but can result in an allergic reaction characterized by mild signs such as hives, itching, or restlessness. Although rare, the allergic reaction could be intense and result in a serious anaphylactic shock reaction. Symptoms associated with anaphylaxis include vomiting, diarrhea, shortness of breath, decreased blood pressure and collapse.1
Not all normal cells can rely totally on their own production of L-asparagine. Cells that normally reproduce rapidly or rely on high levels of protein synthesis are unable to grow or function normally when faced with a depletion of L-asparagine. Therefore, the actions of L-asparaginase are particularly harmful to cells of the intestine, bone marrow, liver, and pancreas and your pet may experience the following side effects:6
Less common side effects include:
Let your veterinarian know if you observe any of these side effects after treatment.
Since L-asparaginase is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur.3 However, if your dog has trouble breathing after the treatment, be sure to seek medical help immediately.4
As mentioned above, be sure to provide your veterinarian with a list of any drugs or supplements your pet may be taking prior to treatment with L-asparaginase. Severe interactions can arise when combined with the following:5
Methotrexate, a commonly used anti-tumor drug, and L-asparaginase work against each other and should be administered at least 48 hours apart. This is also true of vincristine, another chemotherapeutic agent, and administration of vincristine and L-asparaginase should be separated by a few days to prevent adverse interactions.6 Prednisolone, another anti-cancer drug, tends to increase blood sugar levels to a much greater extent when used with L-asparaginase.
Be sure to contact your veterinarian within 24 hours of noticing any of the following symptoms:3
Your vet prescribed L-asparaginase after concluding that its benefits outweigh the risks, but it is important to follow their recommendations closely. If your pet experiences side effects, remember that they often have predictable durations, are reversible, and will go away after the treatment is finished. Most pets do not experience serious side effects.