Favipiravir

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An event is serious (based on the ICH definition) when the patient outcome is:

• * death

• * life-threatening

• * hospitalisation

• * disability

• * congenital anomaly

• * other medically important event

A 62-year-old woman developed erythema and transaminase elevation during treatment with favipiravir for coronavirus disease 2019 (COVID-19) pneumonia.

The woman, who had a history of hypertension and chronic hepatitis B, presented with cough and fever. On day 3, she was hospitalised and was diagnosed with COVID-19 pneumonia. Subsequently, she started receiving favipiravir [route and dosage not stated]. On day 7, her symptoms improved. However, on day 18, she became comatose, followed by convulsive seizures, which were treated with levetiracetam and diazepam. Thereafter, she was transferred to another hospital. On admission, she presented with erythema of the trunk and extremities. She was in a coma with normal light reflex and isocoric pupils. Her extremities were flaccid with increased deep tendon reflexes and positive the Babinski sign. Laboratory examinations revealed increased transaminase levels. Her serum aquaporin-4 and anti-myelin oligodendrocyte glycoprotein antibodies were negative. CSF examination revealed normal cell counts, while protein and myelin basic protein levels were increased. The oligoclonal band was negative while the immunoglobulin G index was 0.59. Her CSF viral polymerase chain reaction and bacterial cultures were negative. The brain MRI with gadolinium revealed diffuse T2/fluid-attenuated inversion recovery hyperintensities in the bilateral white matter with radial linear enhancement oriented to the lateral ventricles. The white matter also revealed hyperintensities on the apparent diffusion coefficient map and diffusion-weighted imaging. The T2-star images had no remarkable changes, while spinal MRI with gadolinium demonstrated no abnormalities. An electroencephalogram revealed diffuse theta waves. Therefore, a diagnosis of COVID-19- associated acute disseminated encephalomyelitis was made. Her transaminase elevation and erythema were attributed to favipiravir [duration of treatment to reaction onset not stated].

Hence, treatment with favipiravir was stopped. On day 19, the woman was intubated and was maintained on unspecified sedatives. She was treated with methylprednisolone for 3 days. Subsequently, her condition improved, and on day 21, she was extubated. Her consciousness became clearer, and by day 23, transaminase levels and erythema improved. However, higher brain dysfunction persisted. On day 33, she received the second course of methylprednisolone, which led to improvement of higher brain dysfunction. On day 46, a follow-up CSF examination showed no abnormalities, and on day 49, the brain MRI revealed significantly improved T2/fluid-attenuated inversion recovery hyperintensities and radial linear enhancement.