Methemoglobinemia induced by dapsone, hydroxychloroquine, and rifampin combination for post-treatment Lyme disease syndrome: A case report.

BACKGROUND

A patient presented to the emergency department with drug-induced methemoglobinemia due to a combination of medications prescribed for post-treatment Lyme disease syndrome (PTLDS). This case highlights the potential risks of dapsone, hydroxychloroquine (HCQ), and rifampin for the management of PTLDS.

CASE SUMMARY: A 62-year-old female presented to the hospital with shortness of breath and low oxygen saturation. Past medical history included a diagnosis of PTLDS, for which she was prescribed a combination of dapsone, HCQ, doxycycline, rifampin, and ivermectin at home. The patient had an oxygen saturation of 88% on room air but was otherwise clinically stable. Arterial blood gas was obtained and demonstrated an elevated methemoglobin level (11.2%). Analysis of peripheral blood smear revealed oxidative hemolysis, indicating medication-induced methemoglobinemia. Glucose-6-phosphate-dehydrogenase (G6PD) testing was ordered to assess for G6PD deficiency, as this is a known risk factor for methemoglobinemia and had not previously been evaluated for this patient. Testing did not demonstrate a G6PD deficiency for this patient. A negative Lyme total antibody test confirmed no active infection. Both dapsone and HCQ are known to induce methemoglobinemia and the addition of rifampin may enhance this effect. Patient improved on supplemental oxygen, ascorbic acid, and discontinuation of dapsone, HCQ, ivermectin, doxycycline, and rifampin therapy.

PRACTICE IMPLICATIONS: There is no strong evidence for any anti-infectives used for the treatment of PTLDS, with either short- or long-term use. Dapsone and HCQ can each cause methemoglobinemia. That effect may be increased when used together, especially in combination with rifampin. Appropriate risk assessment and monitoring should be considered when utilizing this combination.