A severe case of acidosis with concomitant use of avapritinib and metformin requiring emergent hemodialysis

Avapritinib (Ayvakit), a tyrosine kinase inhibitor (TKI), has been recently approved for the treatment of adult patients with unresectable or metastatic gastrointestinal stromal tumor (GIST) who have a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation. New therapeutic agents for malignancy, specifically TKIs, have allowed for major advances in treatment options. Case Report: A 56-yearold male with past medical history significant for GIST of the stomach, who was recently started on a new trial medication ayvakit, presented with nausea, vomiting, and feeling ill. His initial laboratory work was remarkable for blood glucose level of 19 mg/dL, creatinine of 10.41 mg/ dL, potassium of 4.3 mmol/L, anion gap of 41 mmol/L, and arterial blood gas with pH of 6.707, pO2 163 mmHg, pCO2 14 mmHg, and HCO3 of 2 mmol/L on 2 L of nasal cannula oxygen. The patient was in hypovolemic shock secondary to dehydration, hence requiring vasopressors for a short duration. Among the patient’s home medications, it is of significance to mention metformin as a daily medication. He emergently underwent hemodialysis for severe acidosis, with significant improvement in his clinical status. Conclusion: Acidosis can occur as a side effect of therapy or synergistic effect of multiple medications. Avapritinib usage along with medications that are known to have potential to cause acidosis, such as metformin, needs to be cautiously administered. Understanding the potential side effects of new therapy in combination with the patient’s established medications can facilitate the recognition of potential causal relationships. Babajide Adio1, Sepideh Darbandi1 Affiliation: 1DO, Internal Medicine Chief Resident, MercyOne North Iowa Internal Medicine Residency, Mason City, Iowa, USA. Corresponding Author: Babajide Adio, DO, 1000 4th St SW, Mason City, IA 50401, USA; Email: badio@atsu.edu Received: 15 June 2020 Accepted: 27 July 2020 Published: 27 August 2020