Neuromuscular blockade characteristics of cisatracurium in patients receiving chemotherapy: A preliminary study in breast cancer patients.

Background and aims: Cancer chemotherapeutic agents cause alteration in the response to neuromuscular blocking drugs, which can have serious perioperative implications. Magnesium, commonly found to be deficient in these patients, plays an indispensable role in neuromuscular transmission. This study aimed to understand the effect of neoadjuvant chemotherapy on the neuromuscular blocking properties of cisatracurium.

Material and methods: One hundred female patients scheduled for breast cancer surgery were divided into two groups (n = 50 each). Group B received neoadjuvant chemotherapy with taxane, adriamycin, and cyclophosphamide, and Group A did not receive neoadjuvant chemotherapy. Neuromuscular block following cisatracurium 0.15 mg/kg was measured using peripheral nerve stimulator at the ulnar nerve. Onset time, duration of intense block, clinical duration of action, time to TOF4 after the last dose of cisatracurium, along with preoperative serum magnesium concentration were measured. Correlation and multiple regression were run to analyze the relationship between history of neoadjuvant chemotherapy, preoperative magnesium, and the abovementioned time points. Mediation analysis was done to ascertain if magnesium was mediating the observed effects.

Results: Onset time was prolonged by nearly 18% in Group B compared to Group A (P = 0.001). The duration of intense block was 35.27 ± 8.9 min in Group B and 42.07 ± 10.99 min in Group A (P < 0.001). The clinical duration of action of cisatracurium was significantly shorter in Group B (46.06 ± 8.68 min) compared to Group A (55.87 ± 11.04 min, P < 0.001). The time to TOF4 was 32.86 ± 5.66 min in Group B and 36.57 ± 8.49 min in Group A (P < 0.05). Preoperative serum magnesium levels were significantly lower in Group B (P < 0.001).

Conclusion: Patients who had received neoadjuvant chemotherapy had a delayed onset, shorter duration of action, and faster recovery for cisatracurium. Although preoperative magnesium levels were lower in Group B, it was found to be an independent predictor rather than a mediator of these effects.