Interactions
Flucytosine may increase the toxicity of amphotericin B and vice versa, although the combination may be life-saving and should be used whenever indicated (e.g., cryptococcal meningitis). The cytostatic cytarabine inhibits the antimycotic activity of flucytosine. Overdose
Symptoms and their severities are unknown, because flucytosine is used under close medical supervision, but expected to be an excess of the usually encountered side effects on the bone marrow, gastrointestinal tract, liver and kidney function. Vigorous hydration and hemodialysis may be helpful in removing the drug from the body. Hemodialysis is particular useful in patients with impaired renal function. Pharmacology
Mechanisms of action
Two major mechanisms of action have been elucidated:

Flucytosine is intrafungally converted into the cytostatic fluorouracil which undergoes further steps of activation and finally interacts as 5-fluorouridinetriphosphate with RNA biosynthesis thus disturbing the building of certain essential proteins. Flucytosine also undergoes conversion into 5-fluorodeoxyuridinemonophosphate which inhibits fungal DNA synthesis. Spectrum of susceptible fungi and resistance
Flucytosine is active in vitro as well as in vivo against some strains of Candida and Cryptococcus. Limited studies demonstrate that flucytosine may be of value against infections with Sporothrix, Aspergillus, Cladosporium, Exophiala, and Phialophora. Resistance is quite commonly seen as well in treatment-naive patients and under current treatment with flucytosine. In different strains of Candida resistance has been noted to occur in 1 to 50% of all specimens obtained from patients. Pharmacokinetic data
Flucytosine is well absorbed (75 to 90%) from the gastrointestinal tract. Intake with meals slows the absorption, but does not decrease the amount absorbed.
In April 2020, Lawrence Berkeley National Laboratory conducted a X-ray crystallography study at Virs request to investigate how such antibodies bind to SARS-CoV-2 at the molecular level. The Berkeley Lab data helped Vir identify candidates for further study, and Vir eventually settled on a single candidate antibody, S309. Vir collaborated with GlaxoSmithKline to make various refinements to S309, resulting in sotrovimab.Sotrovimab has been engineered to possess an Fc LS mutation (M428L/N434S) that confers enhanced binding to the neonatal Fc receptor resulting in an extended half-life and potentially enhanced drug distribution to the lungs.Sotrovimab has demonstrated activity via two antiviral mechanisms in vitro, antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). Clinical efficacy
The pivotal COMET-ICE study is an ongoing, randomized, double-blind, placebo-controlled study to assess the safety and efficacy of sotrovimab in adults with confirmed COVID-19 (mild, early disease with less than five days of symptoms) at risk of disease progression.An interim analysis of this study reported that sotrovimab reduced the risk of hospitalization for more than 24 hours or death by 85% compared with placebo. Overall 1% of people receiving sotrovimab died or required hospitalization for more than 24 hours compared to 7% of people treated with placebo.