* need for hospitalization in intensive care unit at inclusion * patient with cognitive impairment, at the discretion of the investigator * pregnant woman (positive urine pregnancy test on inclusion) or breastfeeding * participation in another interventional study or being in the exclusion period from a previous study * patient on diltiazem therapy * contraindication to diltiazem * hypersensitivity to diltiazem or to any of the excipients * unaided sinus dysfunction * unaided 2nd and 3rd degree atrioventricular blocks * left ventricular failure with pulmonary stasis (cardiogenic edema) * severe bradycardia (≤ 40 beats per minute) * in combination with: dantrolene infusion, pimozide, dihydroergotamine, ergotamine, nifedipine, ivabradine, beta blockers, antiarrhythmics, esmolol, fingolimod. * patient with renal, hepatic or cardiac insufficiency (at the discretion of the investigator) * hypersensitivity to mannitol * use of anti-covid medications other than those offered in routine testing and care. * presence of hemodynamic instability, systolic blood pressure \< 100 mmhg, presence of multi-visceral failure * prior respiratory pathology requiring oxygen therapy at the long-term and/or non-invasive ventilation * immunocompromised patients (organ transplant, allograft, under chemotherapy, under rituximab or a history of rituximab), for any other situation seek the advice of the coordinating investigator * patient under guardianship, curatorship or safeguard of justice

* need for hospitalization in intensive care unit at inclusion * patient with cognitive impairment, at the discretion of the investigator * pregnant woman (positive urine pregnancy test on inclusion) or breastfeeding * participation in another interventional study or being in the exclusion period from a previous study * patient on diltiazem therapy * contraindication to diltiazem * hypersensitivity to diltiazem or to any of the excipients * unaided sinus dysfunction * unaided 2nd and 3rd degree atrioventricular blocks * left ventricular failure with pulmonary stasis (cardiogenic edema) * severe bradycardia (≤ 40 beats per minute) * in combination with: dantrolene infusion, pimozide, dihydroergotamine, ergotamine, nifedipine, ivabradine, beta blockers, antiarrhythmics, esmolol, fingolimod. * patient with renal, hepatic or cardiac insufficiency (at the discretion of the investigator) * hypersensitivity to mannitol * use of anti-covid medications other than those offered in routine testing and care. * presence of hemodynamic instability, systolic blood pressure \< 100 mmhg, presence of multi-visceral failure * prior respiratory pathology requiring oxygen therapy at the long-term and/or non-invasive ventilation * immunocompromised patients (organ transplant, allograft, under chemotherapy, under rituximab or a history of rituximab), for any other situation seek the advice of the coordinating investigator * patient under guardianship, curatorship or safeguard of justice

need for hospitalization in intensive care unit at inclusion patient with cognitive impairment, at the discretion of the investigator pregnant woman (positive urine pregnancy test on inclusion) or breastfeeding participation in another interventional study or being in the exclusion period from a previous study patient on diltiazem therapy contraindication to diltiazem hypersensitivity to diltiazem or to any of the excipients unaided sinus dysfunction unaided 2nd and 3rd degree atrioventricular blocks left ventricular failure with pulmonary stasis (cardiogenic edema) severe bradycardia (≤ 40 beats per minute) in combination with: dantrolene infusion, pimozide, dihydroergotamine, ergotamine, nifedipine, ivabradine, beta blockers, antiarrhythmics, esmolol, fingolimod. patient with renal, hepatic or cardiac insufficiency (at the discretion of the investigator) hypersensitivity to mannitol use of anti-covid medications other than those offered in routine testing and care. presence of hemodynamic instability, systolic blood pressure < 100 mmhg, presence of multi-visceral failure prior respiratory pathology requiring oxygen therapy at the long-term and/or non-invasive ventilation immunocompromised patients (organ transplant, allograft, under chemotherapy, under rituximab or a history of rituximab), for any other situation seek the advice of the coordinating investigator patient under guardianship, curatorship or safeguard of justice

need for hospitalization in intensive care unit at inclusion patient with cognitive impairment, at the discretion of the investigator pregnant woman (positive urine pregnancy test on inclusion) or breastfeeding participation in another interventional study or being in the exclusion period from a previous study patient on diltiazem therapy contraindication to diltiazem hypersensitivity to diltiazem or to any of the excipients unaided sinus dysfunction unaided 2nd and 3rd degree atrioventricular blocks left ventricular failure with pulmonary stasis (cardiogenic edema) severe bradycardia (≤ 40 beats per minute) in combination with: dantrolene infusion, pimozide, dihydroergotamine, ergotamine, nifedipine, ivabradine, beta blockers, antiarrhythmics, esmolol, fingolimod. patient with renal, hepatic or cardiac insufficiency (at the discretion of the investigator) hypersensitivity to mannitol use of anti-covid medications other than those offered in routine testing and care. presence of hemodynamic instability, systolic blood pressure < 100 mmhg, presence of multi-visceral failure prior respiratory pathology requiring oxygen therapy at the long-term and/or non-invasive ventilation immunocompromised patients (organ transplant, allograft, under chemotherapy, under rituximab or a history of rituximab), for any other situation seek the advice of the coordinating investigator patient under guardianship, curatorship or safeguard of justice