Severe synergistic toxicity from docetaxel in a patient treated concurrently with protease inhibitors as part of HIV post-exposure prophylaxis: a case report

INTRODUCTION: Docetaxel is a semisynthetic taxane commonly used in solid tumour oncology. Its pharmacokinetics has been widely studied, and it is well established that it is metabolized to pharmacologically inactive products by the cytochrome P450 3A iso-enzymes. However, there have been few reports of the consequences of drug interactions between taxanes and other drugs metabolized by the cytochrome P450 pathway. To the best of our knowledge, this is the first case report of the potentially life-threatening interaction that can occur between docetaxel and the protease inhibitors lopinavir and ritonavir. CASE PRESENTATION: A 30-year-old Caucasian woman presented with symptoms suggestive of severe docetaxel toxicity, that is, prolonged myelosuppression, grade 4 mucositis and desquamating rash, following the commencement of post-exposure prophylaxis for a needlestick injury. She had previously received docetaxel chemotherapy with minimal side effects. CONCLUSION: This case report highlights a probable and novel drug interaction between docetaxel and lopinavir and/or ritonavir, which is largely unreported in the medical literature. Even though these interactions may be more relevant in the field of HIV medicine, knowledge of these interactions is also beneficial to oncologists and dermatologists, as well as those providing acute medical care.