1. methemoglobinemia \> 2%; 2. hypotension with systemic blood pressure \< 90/60 mm hg, or uncontrolled hypotension despite vasopressor support; 3. history of sickle cell disease, thalassemia, g6pd deficiency, lung transplant, or allergy to sodium nitrite; 4. hemoglobin \< 8 gm/dl; 5. renal impairment with creatinine clearance \< 60 ml/min/1.73m2; 6. treatment within the past 48 hours with allopurinol (a medication that could interfere with nitrite metabolism); 7. treatment within the past 24 hours with organic nitrates such as nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, sodium nitroprusside, and inhaled nitric oxide; 8. treatment within the past 24 hours with lidocaine, prilocaine, benzocaine, and dapsone; 9. requiring extracorporeal membrane oxygenation (ecmo); 10. subjects with bacterial or fungal infections except for mild cutaneous infections or sinus infections; 11. subjects who are pregnant or lactating; 12. any condition that, in the opinion of the investigator, places the subject at unacceptable risk if he/she were to participate in the study; 13. clinically relevant serious co-morbid medical conditions including, but not limited to, unstable angina, symptomatic congestive heart failure, uncontrolled hypertension, uncontrolled cardiac arrhythmias, uncontrolled chronic obstructive or chronic restrictive pulmonary disease, active central nervous system (cns) disease uncontrolled by standard of care, known positive status for human immunodeficiency virus (hiv) (except if hiv subject has undetectable viral load and a cd4 count of ≥ 500 cells/µl), and/or active hepatitis b or c, cirrhosis, or uncontrolled psychiatric illness/social situations that would limit compliance with study requirements; 14. treatment within 30 days or 5 half-lives of that agent (whichever is shorter) before the first study drug dose using another investigational drug. notwithstanding, prospective subjects who receive any of the following drugs or treatments before the first study drug dose or during this study may be considered for participation in this study: (1) a commercially available, fda-approved drug or treatment used off-label for the treatment of covid-19, or (2) a drug or treatment that has fda emergency use authorization for the treatment of covid-19 patients; 15. moribund or not expected to survive 48 hours.

1. methemoglobinemia \> 2%; 2. hypotension with systemic blood pressure \< 90/60 mm hg, or uncontrolled hypotension despite vasopressor support; 3. history of sickle cell disease, thalassemia, g6pd deficiency, lung transplant, or allergy to sodium nitrite; 4. hemoglobin \< 8 gm/dl; 5. renal impairment with creatinine clearance \< 60 ml/min/1.73m2; 6. treatment within the past 48 hours with allopurinol (a medication that could interfere with nitrite metabolism); 7. treatment within the past 24 hours with organic nitrates such as nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, sodium nitroprusside, and inhaled nitric oxide; 8. treatment within the past 24 hours with lidocaine, prilocaine, benzocaine, and dapsone; 9. requiring extracorporeal membrane oxygenation (ecmo); 10. subjects with bacterial or fungal infections except for mild cutaneous infections or sinus infections; 11. subjects who are pregnant or lactating; 12. any condition that, in the opinion of the investigator, places the subject at unacceptable risk if he/she were to participate in the study; 13. clinically relevant serious co-morbid medical conditions including, but not limited to, unstable angina, symptomatic congestive heart failure, uncontrolled hypertension, uncontrolled cardiac arrhythmias, uncontrolled chronic obstructive or chronic restrictive pulmonary disease, active central nervous system (cns) disease uncontrolled by standard of care, known positive status for human immunodeficiency virus (hiv) (except if hiv subject has undetectable viral load and a cd4 count of ≥ 500 cells/µl), and/or active hepatitis b or c, cirrhosis, or uncontrolled psychiatric illness/social situations that would limit compliance with study requirements; 14. treatment within 30 days or 5 half-lives of that agent (whichever is shorter) before the first study drug dose using another investigational drug. notwithstanding, prospective subjects who receive any of the following drugs or treatments before the first study drug dose or during this study may be considered for participation in this study: (1) a commercially available, fda-approved drug or treatment used off-label for the treatment of covid-19, or (2) a drug or treatment that has fda emergency use authorization for the treatment of covid-19 patients; 15. moribund or not expected to survive 48 hours.

methemoglobinemia > 2%; hypotension with systemic blood pressure < 90/60 mm hg, or uncontrolled hypotension despite vasopressor support; history of sickle cell disease, thalassemia, g6pd deficiency, lung transplant, or allergy to sodium nitrite; hemoglobin < 8 gm/dl; renal impairment with creatinine clearance < 60 ml/min/1.73m2; treatment within the past 48 hours with allopurinol (a medication that could interfere with nitrite metabolism); treatment within the past 24 hours with organic nitrates such as nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, sodium nitroprusside, and inhaled nitric oxide; treatment within the past 24 hours with lidocaine, prilocaine, benzocaine, and dapsone; requiring extracorporeal membrane oxygenation (ecmo); subjects with bacterial or fungal infections except for mild cutaneous infections or sinus infections; subjects who are pregnant or lactating; any condition that, in the opinion of the investigator, places the subject at unacceptable risk if he/she were to participate in the study; clinically relevant serious co-morbid medical conditions including, but not limited to, unstable angina, symptomatic congestive heart failure, uncontrolled hypertension, uncontrolled cardiac arrhythmias, uncontrolled chronic obstructive or chronic restrictive pulmonary disease, active central nervous system (cns) disease uncontrolled by standard of care, known positive status for human immunodeficiency virus (hiv) (except if hiv subject has undetectable viral load and a cd4 count of ≥ 500 cells/µl), and/or active hepatitis b or c, cirrhosis, or uncontrolled psychiatric illness/social situations that would limit compliance with study requirements; treatment within 30 days or 5 half-lives of that agent (whichever is shorter) before the first study drug dose using another investigational drug. notwithstanding, prospective subjects who receive any of the following drugs or treatments before the first study drug dose or during this study may be considered for participation in this study: (1) a commercially available, fda-approved drug or treatment used off-label for the treatment of covid-19, or (2) a drug or treatment that has fda emergency use authorization for the treatment of covid-19 patients; moribund or not expected to survive 48 hours.

methemoglobinemia > 2%; hypotension with systemic blood pressure < 90/60 mm hg, or uncontrolled hypotension despite vasopressor support; history of sickle cell disease, thalassemia, g6pd deficiency, lung transplant, or allergy to sodium nitrite; hemoglobin < 8 gm/dl; renal impairment with creatinine clearance < 60 ml/min/1.73m2; treatment within the past 48 hours with allopurinol (a medication that could interfere with nitrite metabolism); treatment within the past 24 hours with organic nitrates such as nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, sodium nitroprusside, and inhaled nitric oxide; treatment within the past 24 hours with lidocaine, prilocaine, benzocaine, and dapsone; requiring extracorporeal membrane oxygenation (ecmo); subjects with bacterial or fungal infections except for mild cutaneous infections or sinus infections; subjects who are pregnant or lactating; any condition that, in the opinion of the investigator, places the subject at unacceptable risk if he/she were to participate in the study; clinically relevant serious co-morbid medical conditions including, but not limited to, unstable angina, symptomatic congestive heart failure, uncontrolled hypertension, uncontrolled cardiac arrhythmias, uncontrolled chronic obstructive or chronic restrictive pulmonary disease, active central nervous system (cns) disease uncontrolled by standard of care, known positive status for human immunodeficiency virus (hiv) (except if hiv subject has undetectable viral load and a cd4 count of ≥ 500 cells/µl), and/or active hepatitis b or c, cirrhosis, or uncontrolled psychiatric illness/social situations that would limit compliance with study requirements; treatment within 30 days or 5 half-lives of that agent (whichever is shorter) before the first study drug dose using another investigational drug. notwithstanding, prospective subjects who receive any of the following drugs or treatments before the first study drug dose or during this study may be considered for participation in this study: (1) a commercially available, fda-approved drug or treatment used off-label for the treatment of covid-19, or (2) a drug or treatment that has fda emergency use authorization for the treatment of covid-19 patients; moribund or not expected to survive 48 hours.

1. methemoglobinemia > 2%; 2. hypotension with systemic blood pressure < 90/60 mm hg, or uncontrolled hypotension despite vasopressor support; 3. history of sickle cell disease, thalassemia, g6pd deficiency, lung transplant, or allergy to sodium nitrite; 4. hemoglobin < 8 gm/dl; 5. renal impairment with creatinine clearance < 60 ml/min/1.73m2; 6. treatment within the past 48 hours with allopurinol (a medication that could interfere with nitrite metabolism); 7. treatment within the past 24 hours with organic nitrates such as nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, sodium nitroprusside, and inhaled nitric oxide; 8. treatment within the past 24 hours with lidocaine, prilocaine, benzocaine, and dapsone; 9. requiring extracorporeal membrane oxygenation (ecmo); 10. subjects with bacterial or fungal infections except for mild cutaneous infections or sinus infections; 11. subjects who are pregnant or lactating; 12. any condition that, in the opinion of the investigator, places the subject at unacceptable risk if he/she were to participate in the study; 13. clinically relevant serious co-morbid medical conditions including, but not limited to, unstable angina, symptomatic congestive heart failure, uncontrolled hypertension, uncontrolled cardiac arrhythmias, uncontrolled chronic obstructive or chronic restrictive pulmonary disease, active central nervous system (cns) disease uncontrolled by standard of care, known positive status for human immunodeficiency virus (hiv) (except if hiv subject has undetectable viral load and a cd4 count of ≥ 500 cells/µl), and/or active hepatitis b or c, cirrhosis, or uncontrolled psychiatric illness/social situations that would limit compliance with study requirements; 14. treatment within 30 days or 5 half-lives of that agent (whichever is shorter) before the first study drug dose using another investigational drug. notwithstanding, prospective subjects who receive any of the following drugs or treatments before the first study drug dose or during this study may be considered for participation in this study: (1) a commercially available, fda-approved drug or treatment used off-label for the treatment of covid-19, or (2) a drug or treatment that has fda emergency use authorization for the treatment of covid-19 patients; 15. moribund or not expected to survive 48 hours.

1. methemoglobinemia > 2%; 2. hypotension with systemic blood pressure < 90/60 mm hg, or uncontrolled hypotension despite vasopressor support; 3. history of sickle cell disease, thalassemia, g6pd deficiency, lung transplant, or allergy to sodium nitrite; 4. hemoglobin < 8 gm/dl; 5. renal impairment with creatinine clearance < 60 ml/min/1.73m2; 6. treatment within the past 48 hours with allopurinol (a medication that could interfere with nitrite metabolism); 7. treatment within the past 24 hours with organic nitrates such as nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, sodium nitroprusside, and inhaled nitric oxide; 8. treatment within the past 24 hours with lidocaine, prilocaine, benzocaine, and dapsone; 9. requiring extracorporeal membrane oxygenation (ecmo); 10. subjects with bacterial or fungal infections except for mild cutaneous infections or sinus infections; 11. subjects who are pregnant or lactating; 12. any condition that, in the opinion of the investigator, places the subject at unacceptable risk if he/she were to participate in the study; 13. clinically relevant serious co-morbid medical conditions including, but not limited to, unstable angina, symptomatic congestive heart failure, uncontrolled hypertension, uncontrolled cardiac arrhythmias, uncontrolled chronic obstructive or chronic restrictive pulmonary disease, active central nervous system (cns) disease uncontrolled by standard of care, known positive status for human immunodeficiency virus (hiv) (except if hiv subject has undetectable viral load and a cd4 count of ≥ 500 cells/µl), and/or active hepatitis b or c, cirrhosis, or uncontrolled psychiatric illness/social situations that would limit compliance with study requirements; 14. treatment within 30 days or 5 half-lives of that agent (whichever is shorter) before the first study drug dose using another investigational drug. notwithstanding, prospective subjects who receive any of the following drugs or treatments before the first study drug dose or during this study may be considered for participation in this study: (1) a commercially available, fda-approved drug or treatment used off-label for the treatment of covid-19, or (2) a drug or treatment that has fda emergency use authorization for the treatment of covid-19 patients; 15. moribund or not expected to survive 48 hours.