Other substances

Chloroquine phosphate

Plasmodial heme polymerase inhibitor.

Phase of research

Recommended by China's NHC Guidelines

How it helps

Antiviral

Drug status

Used to treat other disease

Supporting references

Contradictory references

AI-suggested references

Clinical trials

General information

Chloroquine phosphate is a phosphate salt of chloroquine, which is an antimalarial drug acting through plasmodial heme polymerase inhibition and some other unknown mechanisms. Its anti-inflamatory activity has been described (NCIt).

Chloroquine therapy is one of the antiviral therapies of COVID-19 recommended by China's National Health Commission guidelines.

On March 28, 2020, the FDA issued the Emergency Use Authorization for chloroquine phosphate for the treatment of COVID-19.

On June 15, 2020, the Emergency Use Authorization for chloroquine phosphate for the treatment of COVID-19 was REVOKED by the FDA.

A living WHO guideline on drugs for covid-19 (as of March 4, 2022) strongly recommends AGAINST the use of chloroquine for the treatment of COVID-19.

Chloroquine phosphate on DrugBank
Chloroquine phosphate on PubChem
Chloroquine phosphate on Wikipedia

Synonyms

Chloroquine diphosphate

Marketed as

ARALEN; ARTRICHIN; BEMAPHATE; CAPQUIN; MALAREX; NIVAQUINE B; RESOQUINE; REUMACHLOR; SANOQUIN

CCN(CC)CCCC(C)NC1=C2C=CC(=CC2=NC=C1)Cl.OP(=O)(O)O.OP(=O)(O)O

Supporting references

Link	Tested on	Impact factor	Notes	Publication date
Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro	VERO E6 cell cultures		Potently blocked virus infection at low-micromolar concentration	Feb/04/2020
In Vitro Antiviral Activity and Projection of Optimized Dosing Design of Hydroxychloroquine for the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).	VERO E6 cell cultures		Less potent than hydroxychloroquine	Mar/09/2020
Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies.	Patients		Is shown to have apparent efficacy and acceptable safety against COVID-19 associated pneumonia	Mar/16/2020
[Expert consensus on chloroquine phosphate for the treatment of novel coronavirus pneumonia].	Patients		Chloroquine phosphate tablet, 500mg twice per day for 10 days for patients diagnosed as mild, moderate and severe cases of novel coronavirus pneumonia and without contraindications to chloroquine	Feb/20/2020
Of chloroquine and COVID-19.	in vitro			Mar/05/2020
Evaluation of Flavonoids as 2019-nCoV Cell Entry Inhibitor Through Molecular Docking and Pharmacological Analysis Preprint In silico	in silico			Apr/06/2020
Discovering drugs to treat coronavirus disease 2019 (COVID-19).	in silico		Oral, 500 mg (300 mg for chloroquine) each time, 2 times/day	Feb/22/2020
National Consumption of Antimalarial Drugs and COVID-19 Deaths Dynamics : an Ecological Study	Patients			Apr/24/2020
Hydroxychloroquine, a less toxic derivative of chloroquine, is effective in inhibiting SARS-CoV-2 infection in vitro	VERO E6 cell cultures		less potent than hydroxychloroquine	Mar/18/2020
Preliminary evidence from a multicenter prospective observational study of the safety and efficacy of chloroquine for the treatment of COVID-19	Patients	16.69	this study provides evidence for safety and efficacy of chloroquine in COVID-19	May/28/2020
Evaluation of 19 antiviral drugs against SARS-CoV-2 Infection Preprint	VERO E6 cell cultures			Apr/29/2020
Identification of an Antiviral Compound from the Pandemic Response Box that Efficiently Inhibits SARS-CoV-2 Infection In Vitro Small molecule In vitro	Vero E6 cells; Calu-3 cells	4.15	at least as potent as Remdesivir	Nov/26/2020
The SARS-CoV-2 cytopathic effect is blocked with autophagy modulators Preprint	VERO E6 cell cultures			May/21/2020
Successful recovery of COVID-19 pneumonia in a patient from Colombia after receiving chloroquine and clarithromycin	Patient		in combination with clarithromycin	Apr/24/2020
A SARS-CoV-2 protein interaction map reveals targets for drug repurposing Small molecule	in silico	42.78		Apr/30/2020
Comparative analysis of antiviral efficacy of FDA-approved drugs against SARS-CoV-2 in human lung cells: Nafamostat is the most potent antiviral drug candidate Preprint	Calu-3 human airway epithelial cells		higher IC50 value in Calu-3 cells than VERO E6 cells	May/12/2020
Enantiomers of Chloroquine and Hydroxychloroquine Exhibit Different Activities Against SARS-CoV-2 in vitro, Evidencing S-Hydroxychloroquine as a Potentially Superior Drug for COVID-19 Preprint	VERO E6 cell cultures		S-enantiomer is 27% more active against SARS-CoV-2 than R-enantiomer	May/27/2020
Broad anti-coronaviral activity of FDA approved drugs against SARS-CoV-2 in vitro and SARS-CoV in vivo Small molecule Animal model	BALB/c mice; A549 lung adenocarcinoma cells expressing ACE2; Vero E6 cells; SARS-CoV-2 strain MA15	4.32	Protected mice infected by mouse-adapded SARS-CoV-2 from clinical disease. Did not inhibit viral replication in the lungs, however. Inhibits the production of infectious viral particles in vitro and decreases viral gene RNA levels.	Aug/19/2020
Efficacy and safety of chloroquine or hydroxychloroquine in moderate type of COVID-19: a prospective open-label randomized controlled study Preprint Randomized controlled open trial Moderate severity	Patients			Jun/22/2020
New Anti SARS-Cov-2 Targets for Quinoline Derivatives Chloroquine and Hydroxychloroquine Envelope protein Small molecule In silico	in silico	4.56	Predicted to have impact on the functionality of the SARS-CoV-2 envelope (E) protein and also to influence proofreading and capping of the viral RNA (lower target energy binding than hydroxyxhloroquine).	Aug/14/2020
Antimalarial drugs inhibit the replication of SARS-CoV-2: An in vitro evaluation Small molecule In vitro	Vero E6 cells; SARS-CoV-2 IHUMI-3 strain	4.59	The antimalarial drug inhibited SARS-CoV-2 in vitro at IC50 and IC90 similar to the concentrations reached during oral antimalarial treatment.	Sep/08/2020
Chloroquine and hydroxychloroquine as ACE2 blockers to inhibit viropexis of 2019-nCoV Spike pseudotyped virus ACE2 Biophysical assay Small molecule In vitro	in silico; in vitro biophysical assay; ACE2 high-expressing HEK293T cells	4.27	Blocks SARS-CoV-2 pseudotyped virus entry into cells in vitro, binds ACE2 in vitro and is slightly less cytotoxic than hydroxychloroquine.	Sep/02/2020
Potential inhibitors for the novel coronavirus (SARS-CoV-2) 3CLpro Small molecule In silico	in silico	8.99	Predicted to inhibit the SARS-CoV-2 3C-like protease.	Sep/18/2020
MCCS: a novel recognition pattern-based method for fast track discovery of anti-SARS-CoV-2 drugs 3CLpro Small molecule In silico	in silico	8.99	In combination with remdesivir. Predicted to inhibit the SARS-CoV-2 3C-like protease.	Oct/20/2020
Calcium channel blocker amlodipine besylate therapy is associated with reduced case fatality rate of COVID-19 patients with hypertension Small molecule In vitro Cohort study	Vero E6 cells; Huh7 cells; COVID-19 patients taking amlodipine besylate for hypertension.	6.26	Inhibited SARS-CoV-2 infection in Vero E6 cells. The inhibitory effect was stronger (additively) when combined with benidipine HCl.	Dec/22/2020
Chloroquine and Hydroxychloroquine Interact Differently with ACE2 Domains Reported to Bind with the Coronavirus Spike Protein: Mediation by ACE2 Polymorphism ACE2 Small molecule In silico	in silico	3.27	Predicted (especially the S enantiomer) to interact with the host's ACE2 receptor to a degree which is influenced by the polymorphisms in the receptor.	Jan/28/2021

AI-suggested references

Link	Publication date
Favipiravir: Pharmacokinetics and Concerns About Clinical Trials for 2019-nCoV Infection.	Apr/21/2020
Effect of High vs Low Doses of Chloroquine Diphosphate as Adjunctive Therapy for Patients Hospitalized With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection: A Randomized Clinical Trial.	Jul/14/2021
A single dose of in situ gel formulation of antimalarial drug chloroquine phosphate as a sustained prophylactic candidate for COVID-19	Mar/11/2022
Potential Antiviral Drugs for SARS-Cov-2 Treatment: Preclinical Findings and Ongoing Clinical Research.	May/03/2020
Hydroxychloroquine as an aerosol might markedly reduce and even prevent severe clinical symptoms after SARS-CoV-2 infection	Apr/27/2020
DFT and molecular docking study of chloroquine derivatives as antiviral to coronavirus COVID-19.	Nov/25/2020
Safety of Chloroquine or Hydroxychloroquine Plus Azithromycin for the Treatment of COVID-19 Patients in Burkina Faso: An Observational Prospective Cohort Study.	Nov/15/2021
A multi-centre, randomized, double-blind, placebo-controlled clinical trial of the efficacy and safety of chloroquine phosphate, hydroxychloroquine sulphate and lopinavir/ritonavir for the treatment of COVID-19 in Lagos State: study protocol for a randomi	Dec/07/2020
High-dose ivermectin for early treatment of COVID-19 (COVER study): a randomised, double-blind, multicentre, phase II, dose-finding, proof-of-concept clinical trial	Jan/06/2022
[Chloroquine phosphate: therapeutic drug for COVID-19].	Aug/11/2021
No difference in biomarkers of ischemic heart injury and heart failure in patients with COVID-19 who received treatment with chloroquine phosphate and those who did not	Aug/16/2021
Safety considerations of chloroquine in the treatment of patients with diabetes and COVID-19	Apr/22/2022
Dose selection of chloroquine phosphate for treatment of COVID-19 based on a physiologically based pharmacokinetic model	Apr/20/2020
Efficacy of chloroquine versus lopinavir/ritonavir in mild/general COVID-19 infection: a prospective, open-label, multicenter, randomized controlled clinical study	Jun/23/2021
Assessment of Recovery Time, Worsening, and Death among Inpatients and Outpatients with COVID-19, Treated with Hydroxychloroquine or Chloroquine plus Azithromycin Combination in Burkina Faso	Oct/30/2020

Clinical trials

ID	Title	Status	Phase	Start date	Completion date
NCT04331600	Chloroquine as Antiviral Treatment in Coronavirus Infection 2020	Completed	Phase 4	Apr/16/2020	Dec/17/2020
Alternative id - WROCLAW CORONA STUDY 2020 Interventions - Drug: Chloroquine phosphate\|Other: Telemedicine Study type - Interventional Study results - No Results Available Locations - Uniwersytecki Szpital Kliniczny, Wrocław, Ul. Borowska 213, Poland\|Wielospecjalistyczny Szpital Miejski, Poznań, Ul. Szwajcarska 3, Poland Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: None (Open Label)\|Primary Purpose: Treatment Enrollment - 16 Age - 18 Years and older (Adult, Older Adult) Outcome measures - COVID-19-related hospitalization or all-cause death\|Decrease in COVID-19 symptoms\|Development of pneumonia\|Development of coronavirus infection-related complications
NCT04328493	The Vietnam Chloroquine Treatment on COVID-19	Completed	Phase 2	Apr/07/2020	Sep/10/2020
Alternative id - COVID Interventions - Drug: Chloroquine phosphate Study type - Interventional Study results - No Results Available Locations - National Hospital for Tropical Diseases, Hanoi, Vietnam\|Can Gio COVID Hospital, Ho Chi Minh City, Vietnam\|Cho Ray Hospital, Ho Chi Minh City, Vietnam\|Cu Chi COVID Hospital, Ho Chi Minh City, Vietnam\|Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: None (Open Label)\|Primary Purpose: Treatment Enrollment - 10 Age - 18 Years and older (Adult, Older Adult) Outcome measures - Viral clearance time\|Length of hospital stay\|Ventilator free days\|Oxygen free days\|Time to death\|Adverse events\|fever clearance time\|Ordinal outcome scale\|Development of ARDS
NCT04428268	Chloroquine + Losartan Compared to Chloroquine Alone for the Treatment of COVID-19 Pneumonia	Withdrawn	Phase 2	Mar/10/2020	Feb/16/2021
Alternative id - IF20-00003 Interventions - Drug: Chloroquine Phosphate Tablets Study type - Interventional Study results - No Results Available Locations - Hospital Universitario José E. Gonzalez, Monterrey, Nuevo Leon, Mexico Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: Double (Investigator, Outcomes Assessor)\|Primary Purpose: Treatment Enrollment - 0 Age - 18 Years and older (Adult, Older Adult) Outcome measures - Overall mortality\|Clinical outcome assessment\|Number of participants with treatment-related adverse events as assessed by CTCAE v4.0\|Time to negative SARS-CoV-2 test
NCT04323527	Chloroquine Diphosphate for the Treatment of Severe Acute Respiratory Syndrome Secondary to SARS-CoV2	Completed	Phase 2	Mar/23/2020	Jun/07/2020
Alternative id - CAAE: 30152620.1.0000.0005 Interventions - Drug: Chloroquine diphosphate Study type - Interventional Study results - No Results Available Locations - Hospital e Pronto Socorro Delphina Rinaldi Abdel Aziz, Manaus, Amazonas, Brazil Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)\|Primary Purpose: Treatment Enrollment - 278 Age - 18 Years and older (Adult, Older Adult) Outcome measures - Mortality rate reduction of 50% by day 28\|Absolute mortality on days 7 and 14\|Improvement in overall subject's clinical status assessed in standardized clinical questionnaires on days 14 and 28\|Improvement in daily clinical status assessed in standardized clinical questionnaires during hospitalization\|Duration of supplemental oxygen (if applicable)\|Duration of mechanical ventilation (if applicable)\|Absolute duration of hospital stay in days\|Prevalence of grade 3 and 4 adverse events\|Prevalence of serious adverse events\|Change in serum creatinine level\|Change in serum troponin I level\|Change in serum aspartate aminotransferase level\|Change in serum CK-MB level\|Change in detectable viral load in respiratory tract swabs\|Viral concentration in blood samples\|Absolute number of causes leading to participant death (if applicable)
NCT04286503	The Clinical Study of Carrimycin on Treatment Patients With COVID-19	Unknown status	Phase 4	Feb/23/2020	Feb/28/2021
Alternative id - BeijingYouan Hospital Interventions - Drug: Carrimycin\|Drug: lopinavir/ritonavir tablets or Arbidol or chloroquine phosphate\|Drug: basic treatment Study type - Interventional Study results - No Results Available Locations - Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: None (Open Label)\|Primary Purpose: Treatment Enrollment - 520 Age - 18 Years to 75 Years (Adult, Older Adult) Outcome measures - Fever to normal time (day)\|Pulmonary inflammation resolution time (HRCT) (day)\|Negative conversion (%) of 2019-nCOVRNA in gargle (throat swabs) at the end of treatment
NCT04443270	Chloroquine Phosphate Prophylactic Use in Health Personnel Exposed to COVID-19 Patients	Not yet recruiting	Phase 1	Jul/27/2020	Jan/31/2021
Alternative id - 01 Interventions - Drug: Chloroquine phosphate Study type - Interventional Study results - No Results Available Locations - Centro Médico Nacional "20 de Noviembre", Mexico City, Benito Juárez, Mexico Study designs - Allocation: Non-Randomized\|Intervention Model: Parallel Assignment\|Masking: Single (Outcomes Assessor)\|Primary Purpose: Prevention Enrollment - 200 Age - 18 Years to 59 Years (Adult) Outcome measures - Negative Polymerase Chain Reaction assay at day 0\|Polymerase Chain Reaction assay at day 60\|Clinical improvement related to COVID-19\|Heart rhythm negative adverse event related to the Chloroquine Phosphate Prophylactic Use\|Heart rhythm negative adverse event related to the Chloroquine Phosphate Prophylactic\|COVID-19 symptomatic onset rate
NCT04342650	Chloroquine Diphosphate in the Prevention of SARS in Covid-19 Infection	Completed	Phase 2	Apr/08/2020	Jun/08/2020
Alternative id - CAAE: 30504220.5.0000.0005 Interventions - Drug: Chloroquine Diphosphate\|Drug: Placebo oral tablet Study type - Interventional Study results - No Results Available Locations - Hospital e Pronto Socorro Delphina Rinaldi Abdel Aziz, Manaus, Amazonas, Brazil Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)\|Primary Purpose: Treatment Enrollment - 152 Age - 18 Years and older (Adult, Older Adult) Outcome measures - Proportion of patients with onset of severe acute respiratory syndrome (SARS)\|Mortality rate\|Number of participants in need of intensive care support\|Viral concentration\|Cumulative incidence of serious adverse events\|Cumulative incidence of grade 3 and 4 adverse events\|Proportion of patients with discontinued treatment\|Incidence of cardiac lesions\|Incidence of cardiac disfunctions\|Change in respiratory capacity
NCT04344951	Chloroquine Phosphate Against Infection by the Novel Coronavirus SARS-CoV-2 (COVID-19): The HOPE Open-Label, Non Randomized Clinical Trial	Terminated	Phase 2	Apr/06/2020	Nov/30/2020
Alternative id - UNIKINON-01/HOPE Interventions - Drug: UNIKINON (Chloroquine phosphate) 200mg tablets Study type - Interventional Study results - No Results Available Locations - Divine Providence Hospital "Pammakaristos", Athens, Greece\|Athens General Hospital "Hippokrateio", Athens, Greece\|Athens General Hospital of Thoracic Diseases "SOTIRIA", 1st University Pulmonary Clinic, Athens, Greece\|Athens General Hospital of Thoracic Diseases "SOTIRIA", 3rd University Pathology Clinic, Athens, Greece\|Corfu General Hospital Agia Irini, Corfu, Greece\|University General Hospital of Ioannina, Ioánnina, Greece\|General Hospital of Athens "Sismanoglio", Maroúsi, Greece\|University General Hospital of Thessaloniki AHEPA, Thessaloníki, Greece Study designs - Allocation: N/A\|Intervention Model: Single Group Assignment\|Masking: None (Open Label)\|Primary Purpose: Prevention Enrollment - 29 Age - 18 Years to 90 Years (Adult, Older Adult) Outcome measures - 50% reduction in symptom score for patients with lower respiratory tract infection\|Lack of progression for patients with upper respiratory tract infection\|Comparison of the primary endpoint with respective patients not receiving the treatment\|Serious respiratory failure until day 14. This will be compared with respective patients not receiving the treatment.\|Frequency of AEs and SAEs
NCT04319900	Clinical Trial of Favipiravir Tablets Combine With Chloroquine Phosphate in the Treatment of Novel Coronavirus Pneumonia	Unknown status	Phase 2\|Phase 3	Mar/05/2020	Jun/25/2020
Alternative id - 2020-K-24-2 Interventions - Drug: favipiravir tablets+chloroquine phosphatetablets tablets\|Drug: Favipiravir tablets\|Drug: Placebo Study type - Interventional Study results - No Results Available Locations - Beijing Chaoyang hospital, Beijing, Beijing, China Study designs - Allocation: Randomized\|Intervention Model: Parallel Assignment\|Masking: Double (Participant, Care Provider)\|Primary Purpose: Treatment Enrollment - 150 Age - 18 Years to 75 Years (Adult, Older Adult) Outcome measures - Time of Improvement or recovery of respiratory symptoms\|Number of days virus nucleic acid shedding\|Frequency of Improvement or recovery of respiratory symptoms\|Duration of fever\|Frequencies of progression to severe illness\|Time of improvement of pulmonary imaging\|Peripheral blood c-reactive protein concentration\|Absolute value of peripheral blood lymphocytes\|percentage of peripheral blood lymphocytes

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