Vol.74 No.5 September 2026
A case of severe fever with thrombocytopenia syndrome in an elderly patient in whom a favorable outcome was achieved despite initiation of favipiravir only on day 6 after symptom onset: importance of assessing treatment indication based on the clinical condition at the time of initiation
1)Department of Hospital Pharmacy, Chugoku Central Hospital, 148-13 Kamiiwanari Miyuki-Cho, Fukuyama, Hiroshima, Japan
2)Department of Infectious Diseases, Chugoku Central Hospital
Abstract
Severe fever with thrombocytopenia syndrome (SFTS) is known to be associated with poor clinical outcomes in patients with poor prognostic factors such as advanced age and a prolonged interval between symptom onset and treatment initiation. However, the influence on the therapeutic efficacy of the patient's clinical condition at the time of treatment initiation has not yet been sufficiently clarified. The patient was a 78-year-old woman who was diagnosed as having SFTS on day 6 after symptom onset and started on favipiravir therapy. On admission, leukopenia, thrombocytopenia, and elevated liver enzyme and lactate dehydrogenase levels were observed; however, there were no hemorrhagic manifestations or disturbance of consciousness. The serum C-reactive protein level was low, and there was no marked coagulopathy or evidence of multiple organ failure. Hepatic functional reserve was preserved, and favipiravir treatment was administered at the standard dosage in accordance with the instructions on the package insert. Although the patient developed hyperuricemia during treatment, concomitant administration of febuxostat allowed completion of the 10-day course of favipiravir without interruption, with a favorable outcome. This case suggests the importance of taking into account the patient's clinical condition at the time of treatment initiation in determining the indication for favipiravir therapy.
Key word
severe fever with thrombocytopenia syndrome, tick-borne disease, favipiravir, elderly, severity
Received
October 10, 2025
Accepted
May 26, 2026
Jpn. J. Chemother. 74 (5): 563-568, 2026
