Prophylactic use of duloxetine hydrochloride in oxaliplatin-induced first-bite syndrome.

First-bite syndrome (FBS) is manifested as acute and severe pain in the parotid region occurring at the first bite of a meal. While most cases of FBS arise after surgeries involving the deep lobe of the parotid gland, chemotherapy-induced FBS is extremely rare. Some adverse effects of oxaliplatin resemble FBS, suggesting it may be under-recognized. Here, we present a case of a 72 year-old male with oxaliplatin-induced FBS, effectively managed with the prophylactic administration of duloxetine hydrochloride. The patient, with a history of surgery for appendiceal adenocarcinoma, experienced sharp pain in the bilateral parotid regions at the beginning of each meal after the second to fourth courses of adjuvant chemotherapy with CapeOX (oxaliplatin and capecitabine). He was subsequently referred to our department for evaluation. Upon examination, no organic diseases were identified. Given the reproducible nature of the symptoms, oxaliplatin-induced FBS was diagnosed. We commenced prophylactic duloxetine hydrochloride before the fifth and sixth courses of chemotherapy, which significantly reduced the pain. After completing six courses of oxaliplatin, the patient no longer experienced symptoms of FBS, even without the continued administration of duloxetine hydrochloride. This case highlights that oxaliplatin can induce FBS, which can be effectively managed with duloxetine hydrochloride.