Side Effects of Paclitaxel
Most Paclitaxel patients lose their hair - it usually grows back - and experience some nausea or vomiting. Patients are also at increased risk of infection because your immune system is compromised. Chemotherapy drugs tend to have dose-limiting toxicity in one organ system. For Paclitaxel that system is the bone marrow, and myelosuppression, a weakening of the immune system, is common. Indeed, the most common side effect appears to be lowering of blood cell counts.
A diagnostic test called the absolute neutrophil count is given to patients, and generally those with a white blood cell count below 1500 cells/mm^3 (before any chemo treatment) are not given Paclitaxel. When patients in the course of a treatment get severe neutropenia (neutrophil <500 cells/mm3) it is common for the treating oncologist to lower the dosage by about 20%. Doctors also check to ensure that the platelet count is >=100,000 cells/mm3.
Cancer results in uncontrolled growth of malignant cells in the body. These cells are destroyed by Paclitaxel and other anticancer drugs that prevent them from multiplying rapidly. However, normal healthy cells may also get damaged and side effects are usually a result of damage done to these cells. Cells more susceptible to damage are the fast-growing normal cells that include blood cells present in the bone marrow and cells present in the mouth, stomach, intestines, and esophagus that together make up the digestive tract. Since hair follicles can also be affected, hair loss may occur during chemotherapy.
Common side effects include
- hair loss (scientific name: alopecia)
- nausea and vomiting
- mouth sores
- low blood cell count (either red cells or white cells or both)
Less common but more serious side effects are
- chest pain
- irregular heartbeat (bradycardia)
- usual bleeding or bruising
- hypotension (low blood pressure
- numbness and pain in hands (peripheral neuropathy)
If your Paclitaxel affects your lungs, heart, kidneys, bladder and nervous system, let your doctor know right away. Also inform your doctor about unusual bleeding or numbness or tingling in fingers or toes.
Paclitaxel patients (both male and female) should use contraception if there is any chance of pregnancy. Tests in animals show Paclitaxel harms embryos, fetuses, and expecting mothers. It is never given to pregnant women. Breast-feeding women are never given Paclitaxel.
Interactions with other Chemotherapy Drugs
Paclitaxel is often given as part of a combination chemotherapy regimen. Oncologists have to weigh many factors in determining the best regimen and the potential interactions between drugs. The monoclonal antibody trastuzumab seems to have more severe cardiovascular side effects when combined with Paclitaxel. Topotecan, etoposide, and doxorubicin are all known to increase the chances of adverse reactions when taken with Paclitaxel. The widely used chemotherapy drug Cisplatin - when taken with Paclitaxel the negative effect on white blood cell count is more pronounced. The timing of the delivery of these drugs is important.