*3.4. Remdesivir in Patients with Impaired Renal Function*

Remdesivir, a therapy originally developed to treat hepatitis C and Ebola, is used in treating selected patients with COVID-19. In three (17%) patients, due to an impaired renal function, remdesivir formally was contraindicated. One of them was on chronic intermittent hemodialysis, the other two had an eGFR < 30 mL/min. In patients with hemodialysis (HD), to the best of our knowledge, there are no clinical data or guidelines how to treat these patients with remdesivir. At the University Hospital of Zurich, remdesivir in HD patients, starts with 200 mg on the first day of HD, followed by 100 mg on the third and fifth day.

On the first day, the maximal concentration (Cmax) is measured immediately after the first remdesivir infusion, followed by measurements of Cmax after 2–3 h. On the second day, the minimal concentration, Cmin, is measured 24h after the first remdesivir dose. On day three, Cmin is measured before and after dialysis, and Cmax immediately after the second dose and also three hours later. On the fourth day, Cmin is measured 24h after the second dose (trough). On the fifth day, Cmin is measured before HD and after HD. The Cmax is measured after the infusion of the last dose, as well as 3 h later. Currently, the Cmax values are experimentally and help to find the area under the curve (AUC), after which dose adjustments can be considered. However, in case the dose is not in the target range, dosage adjudgments are empirical. Additionally, in patients with renal failure but without HD, remdesivir treatment consists of three doses: On the first day 200 mg are given followed by remdesivir 100 mg every 48 h (remdesivir on day 1, 3 and 5).
