Case Report: A case of carbapenem hypersensitivity and tigecycline-associated coagulopathy after immunotherapy for advanced oral cancer.
Managing complex infections after immunotherapy in patients with advanced head and neck cancer is clinically challenging, especially when severe adverse drug reactions like carbapenem hypersensitivity and tigecycline-associated coagulopathy further limit treatment options. This case demonstrates the potential contribution of clinical pharmacists in such difficult scenarios. A 74-year-old man with oral squamous cell carcinoma developed severe sepsis after one cycle of PD-1 inhibitor (penpulimab) plus EGFR inhibitor (cetuximab). The clinical pharmacist sequentially recommended escalation to meropenem, switch to piperacillin-tazobactam, and addition of vancomycin. Later, the pharmacist recognized possible imipenem-related central nervous system effects, leading to discontinuation of all carbapenems due to possible cross-hypersensitivity. Subsequently, tigecycline was initiated, its associated coagulopathy was managed, and a switch to doxycycline was made. The patient's fever resolved, and coagulation substantially improved; the infection was finally controlled. Causality was assessed using the Naranjo scale (imipenem 7, meropenem 5) and the RUCAM scale (penpulimab 6). In this case, the clinical pharmacist's dynamic assessment and use of quantitative adverse reaction tools (Naranjo and RUCAM scales) contributed to successful infection control and management of drug toxicity.