* 1. have an oxygen saturation of \<90% while breathing ambient air. 2. any physical examination findings and/or history of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject. 3. nursing women or women of childbearing potential (wocbp) with a positive pregnancy test. 4. treatment with another dhodh inhibitor (e.g., leflunomide, teriflunomide) or other agents known to cause bone marrow suppression leading to thrombocytopenia. 5. ongoing treatment with aspirin and or dipyridamole, famotidine or cimetidine. remdesivir and ivermectin are prohibited through study day 8. steroids are permitted per the guidelines. 6. platelets ≤125,000 cell/mm3. 7. hemoglobin \<10 gm/dl. 8. absolute neutrophil count \<1000 cells/mm3. 9. renal dysfunction, i.e., creatinine clearance \<30 ml/min. 10. ast or alt \>3 x uln, or total bilirubin \>uln. gilbert's syndrome is allowed. 11. bleeding disorders or blood loss requiring transfusion in the six weeks preceding enrollment. 12. ongoing gastrointestinal ulcer, or gastrointestinal bleeding within 6 weeks of first dose. 13. chronic hepatitis b infection, active hepatitis c infection, active liver disease and/or cirrhosis per subject report. 14. heart failure, current uncontrolled cardiovascular disease, including unstable angina, uncontrolled arrhythmias, major adverse cardiac event within 6 months (e.g., stroke, myocardial infarction, hospitalization due to heart failure, or revascularization procedure).

* 1. have an oxygen saturation of \<90% while breathing ambient air. 2. any physical examination findings and/or history of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject. 3. nursing women or women of childbearing potential (wocbp) with a positive pregnancy test. 4. treatment with another dhodh inhibitor (e.g., leflunomide, teriflunomide) or other agents known to cause bone marrow suppression leading to thrombocytopenia. 5. ongoing treatment with aspirin and or dipyridamole, famotidine or cimetidine. remdesivir and ivermectin are prohibited through study day 8. steroids are permitted per the guidelines. 6. platelets ≤125,000 cell/mm3. 7. hemoglobin \<10 gm/dl. 8. absolute neutrophil count \<1000 cells/mm3. 9. renal dysfunction, i.e., creatinine clearance \<30 ml/min. 10. ast or alt \>3 x uln, or total bilirubin \>uln. gilbert's syndrome is allowed. 11. bleeding disorders or blood loss requiring transfusion in the six weeks preceding enrollment. 12. ongoing gastrointestinal ulcer, or gastrointestinal bleeding within 6 weeks of first dose. 13. chronic hepatitis b infection, active hepatitis c infection, active liver disease and/or cirrhosis per subject report. 14. heart failure, current uncontrolled cardiovascular disease, including unstable angina, uncontrolled arrhythmias, major adverse cardiac event within 6 months (e.g., stroke, myocardial infarction, hospitalization due to heart failure, or revascularization procedure).

1. have an oxygen saturation of <90% while breathing ambient air. 2. any physical examination findings and/or history of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject. 3. nursing women or women of childbearing potential (wocbp) with a positive pregnancy test. 4. treatment with another dhodh inhibitor (e.g., leflunomide, teriflunomide) or other agents known to cause bone marrow suppression leading to thrombocytopenia. 5. ongoing treatment with aspirin and or dipyridamole, famotidine or cimetidine. remdesivir and ivermectin are prohibited through study day 8. steroids are permitted per the guidelines. 6. platelets ≤125,000 cell/mm3. 7. hemoglobin <10 gm/dl. 8. absolute neutrophil count <1000 cells/mm3. 9. renal dysfunction, i.e., creatinine clearance <30 ml/min. 10. ast or alt >3 x uln, or total bilirubin >uln. gilbert's syndrome is allowed. 11. bleeding disorders or blood loss requiring transfusion in the six weeks preceding enrollment. 12. ongoing gastrointestinal ulcer, or gastrointestinal bleeding within 6 weeks of first dose. 13. chronic hepatitis b infection, active hepatitis c infection, active liver disease and/or cirrhosis per subject report. 14. heart failure, current uncontrolled cardiovascular disease, including unstable angina, uncontrolled arrhythmias, major adverse cardiac event within 6 months (e.g., stroke, myocardial infarction, hospitalization due to heart failure, or revascularization procedure).

1. have an oxygen saturation of <90% while breathing ambient air. 2. any physical examination findings and/or history of any illness that, in the opinion of the study investigator, might confound the results of the study or pose an additional risk to the subject. 3. nursing women or women of childbearing potential (wocbp) with a positive pregnancy test. 4. treatment with another dhodh inhibitor (e.g., leflunomide, teriflunomide) or other agents known to cause bone marrow suppression leading to thrombocytopenia. 5. ongoing treatment with aspirin and or dipyridamole, famotidine or cimetidine. remdesivir and ivermectin are prohibited through study day 8. steroids are permitted per the guidelines. 6. platelets ≤125,000 cell/mm3. 7. hemoglobin <10 gm/dl. 8. absolute neutrophil count <1000 cells/mm3. 9. renal dysfunction, i.e., creatinine clearance <30 ml/min. 10. ast or alt >3 x uln, or total bilirubin >uln. gilbert's syndrome is allowed. 11. bleeding disorders or blood loss requiring transfusion in the six weeks preceding enrollment. 12. ongoing gastrointestinal ulcer, or gastrointestinal bleeding within 6 weeks of first dose. 13. chronic hepatitis b infection, active hepatitis c infection, active liver disease and/or cirrhosis per subject report. 14. heart failure, current uncontrolled cardiovascular disease, including unstable angina, uncontrolled arrhythmias, major adverse cardiac event within 6 months (e.g., stroke, myocardial infarction, hospitalization due to heart failure, or revascularization procedure).