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Background and Aims With the SARS-CoV-2 pandemic, regional anesthesia techniques gained more impact because of the need to avoid airway manipulation. To assure a fast recovery and ambulation, prilocaine was used more frequently due to its fast onset and lower duration of action.

Methods We describe a case of methemoglobinemia in a patient submitted to a uterine aspiration after an abortion during the first trimester.

Results The patient weighted 50kg and had a medical history of ulcerative colitis medicated with sulfasalazine. She was anesthetized with spinal anesthesia with 60mg of hyperbaric prilocaine. After 17 minutes of the spinal technique the oxygen saturation dropped from 98-99% to 90% and a bluish discoloration on her lips was detected. With the assumption of a case of methemoglobinemia associated with prilocaine administration, methylene blue 1mg/kg was administered (50mg). The procedure was terminated, and she was admitted for surveillance. The case resolved with no complications.

Conclusions Methemoglobinemia is a rare complication associated with prilocaine. Normally higher doses are associated with the development of this syndrome. Sulfasalazine and other drugs administration may enhance the probability of the occurrence of methemoglobinemia. Methylene blue is an effective antidote for methemoglobinemia due to its own oxidizing properties.