Paclitaxel linked to severe allergies, FDA requires warnings and preventive medication

To ensure drug safety for the public, the Food and Drug Administration requires drug labels for paclitaxel containing castor oil solvent to include an allergy warning.

The chemotherapy drug paclitaxel, which is commonly used in the treatment of breast cancer, lung cancer, ovarian cancer and other cancers, has been reported to have serious allergic risks. The Food and Drug Administration of the Ministry of Health and Welfare received suspected cases of severe allergic reactions resulting in death after the use of paclitaxel, and further initiated a re-evaluation of the clinical benefits and risks of the drug. As of April 18 this year, a total of 28 reports of severe allergic reactions were reported in China after the use of paclitaxel, a solvent containing castor oil, 9 of which were life-threatening. The Food and Drug Administration requires relevant drug license holders to modify the Chinese leaflets to include safety information such as allergic reactions and preventive medication.

Jian Renjizheng and Liu Jiaping from the Drug Group of the Food and Drug Administration said that allergic reactions caused by paclitaxel are mainly related to the polyoxyethylene castor oil (Cremophor EL) component in the excipient. After receiving a suspected death case of severe allergic reaction symptoms after using paclitaxel, the Food and Drug Administration initiated a re-evaluation of the clinical benefits and risks of drugs containing paclitaxel, a castor oil solvent, in order to ensure the safety of people taking the drug.

According to statistics from the National Adverse Drug Reaction Notification System, as of April 18, 2026, a total of 28 reports of suspected severe allergic reactions have been received after using drugs containing the castor oil solvent paclitaxel. Among them, 9 were life-threatening, 5 resulted in hospitalization or prolonged hospitalization, and 14 were other complications that may cause permanent harm.

Liu Jiaping pointed out that the correlation between adverse reactions in most reported cases and the use of paclitaxel was assessed as "possible" or "extremely likely". After completing the re-evaluation, the Food and Drug Administration has required relevant drug license holders to change the Chinese instructions and add safety information on allergic reactions and preventive medication.

According to the announcement from the Food and Drug Administration, about 2% to 4% of patients taking paclitaxel may experience allergic reactions and severe allergic reactions. Symptoms include dyspnea, hypotension requiring treatment, angioedema and generalized urticaria; even if prophylactic medication is given in advance, fatal reactions may still occur.

Therefore, all patients must take corticosteroids, diphenhydramine, H2 antagonists and other drugs before receiving treatment; if patients have experienced severe allergic reactions to paclitaxel, they should not try to use this drug again.

Currently, there are 7 approved domestic drug licenses containing the ingredient paclitaxel, a castor oil solvent. The main indications include advanced ovarian cancer, breast cancer with axillary lymph node metastasis, non-small cell lung cancer, and second-line therapy for AIDS-related Kaposi's sarcoma.

The clinical use of these drugs is not low. According to the government's public information "National Health Insurance Drug Declaration Volume" from the National Health Insurance Administration, the declared dosage of drugs containing the castor oil solvent paclitaxel in 2025 reached 205,745. The Food and Drug Administration requested to modify the Chinese instruction manual this time, hoping to further reduce the risk of clinical medication by strengthening allergic reaction warnings and preventive medication information.