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AMR Drug RepurposingSmart Screeningresearch prototype

Primaquine Phosphate

FDA-approved product (tablet, oral), marketed as Primaquine, Primaquine Phosphate.

Registered studies
50+
Lab records
1
Pathogens at ≥40%
1 of 4

Chemical structure

Chemical structure of Primaquine Phosphate
A drawing shows what the molecule is, not what it does.

Existing / approved use

Documented · FDA, WHO, ChEMBL

Approved for

  • Malaria

Indications ChEMBL records as approved, from FDA and DailyMed labels.

WHO therapeutic group
Aminoquinolines
Anti-infective classification
Classified as another kind of anti-infective (for example an antifungal, antiviral or antiparasitic medicine).WHO ATC P01BA03

Repurposing investigation

This medicine is being investigated here for AI-predicted antimicrobial activity against M. tuberculosis. It was surfaced computationally for further investigation; it is not an established treatment for this infection.

AI-predicted activity

AI prediction · nothing measured
  • MRSA38.9% AI-predicted activityBelow the ≥40% mark this site uses to surface candidates.
  • E. coli26.3% AI-predicted activityBelow the ≥40% mark this site uses to surface candidates.
  • K. pneumoniae17.8% AI-predicted activityBelow the ≥40% mark this site uses to surface candidates.
  • M. tuberculosis59.4% AI-predicted activityAt or above the ≥40% mark this site uses to surface candidates. This medicine was in the model's training data, so this is recall, not a new prediction.

A model’s estimate of laboratory activity against each pathogen species. It is not clinical effectiveness.

Evidence

Clinical and experimental

Documented evidence

Clinical

50+registered studies name this medicine, for any condition. The registry search keeps the first 50, so there may be more. See them below.

Experimental

  • M. tuberculosis: measured active in 0 of 1 lab record
Open Primaquine Phosphate in ChEMBL Registered studies below
Show the 1 laboratory record, with sources

Loading records…

“Active” means the measured value reached this project’s laboratory cutoff (10 µM or stronger). A laboratory result does not show an effect in patients.

Docking

Computational · nothing measured

Dihydrofolate reductase ↗ (E. coli)

-6.7 kcal/mol

0better fit →-12

KPC-2 carbapenemase ↗ (K. pneumoniae)

-6.3 kcal/mol

0better fit →-12

Enoyl-ACP reductase (InhA) ↗ (M. tuberculosis)

-5.7 kcal/mol

0better fit →-12

Dihydrofolate reductase ↗ (MRSA)

-7.2 kcal/mol

0better fit →-12

AutoDock Vina, one experimentally solved protein per pathogen. This project’s screening target is -7.0 kcal/mol, its own mark rather than a universal cutoff. A docking score is a structural hypothesis, not proof of binding, and requires experimental validation.

Other medicines to investigate

AI prediction · nothing measured

Other repurposing candidates: approved medicines besides Primaquine Phosphate with AI-predicted activity ≥40% against the chosen pathogen, leaving out existing antimicrobials. They are computational candidates for further investigation, not alternatives and not recommendations.

Sorted by AI-predicted activity, high to low. The order is not a ranking of which medicine is better.

Registered studies

A registration describes a study; it does not establish a positive result.

  • Serological Testing and Treatment for Plasmodium Vivax Malaria: a Trial in Ethiopia and Madagascar

    NCT06923592 · start 2025-05-12

    Registered record
    Registry ID
    NCT06923592
    Conditions
    Malaria Vivax; Malaria Falciparum; Plasmodium Vivax; Plasmodium Falciparum
    Interventions
    PvSeroTAT; Control
    Study type
    INTERVENTIONAL
    Phase
    Phase 3
    Registry status
    Recruiting
    Start
    2025-05-12
    Completion
    2027-04-28
    Enrolment
    19,200

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria Vivax; Malaria Falciparum; Plasmodium Vivax; Plasmodium Falciparum
    InterventionPvSeroTAT; Control
    PhasePhase 3
    Registry statusRecruiting

  • Efficacy of Chloroquine-Primaquine Treatment for Uncomplicated Plasmodium Vivax Malaria

    NCT07753967 · start 2024-12-01

    Registered record
    Registry ID
    NCT07753967
    Conditions
    Malaria Vivax
    Interventions
    CQ-PQ
    Study type
    INTERVENTIONAL
    Phase
    Not applicable
    Registry status
    Completed
    Start
    2024-12-01
    Completion
    2025-11-30
    Enrolment
    192

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria Vivax
    InterventionCQ-PQ
    PhaseNot applicable
    Registry statusCompleted

  • An Interventional Study to Compare the Efficacy and Safety of Tafenoquine (TQ) and Primaquine (PQ) When Either Are Taken Together With Chloroquine (CQ) for the Treatment of P. Vivax Malaria in Indian Participants Aged 2 Years and Older

    NCT06666491 · start 2024-11-13

    Registered record
    Registry ID
    NCT06666491
    Conditions
    Malaria, Vivax
    Interventions
    Tafenoquine; Primaquine; Chloroquine
    Study type
    INTERVENTIONAL
    Phase
    Phase 3
    Registry status
    Recruiting
    Start
    2024-11-13
    Completion
    2026-05-25
    Enrolment
    300

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria, Vivax
    InterventionTafenoquine; Primaquine; Chloroquine
    PhasePhase 3
    Registry statusRecruiting

  • Primaquine for Vivax Malaria in G6PD Intermediate and Deficient Cases.

    NCT07468513 · start 2024-05-17

    Registered record
    Registry ID
    NCT07468513
    Conditions
    Vivax Malaria; G6PD Deficiency
    Interventions
    Patients with G6PD enzyme activities between 30 and <70% of the AMM will be treated with schizontocidal treatment plus high dose primaquine 1mg/kg/day for 7 days; Patients with G6PD enzyme activities <30% of the AMM will be treated with schizontocidal treatment plus 8 weekly primaquine (0.75mg/kg dose).
    Study type
    INTERVENTIONAL
    Phase
    Phase 4
    Registry status
    Recruiting
    Start
    2024-05-17
    Completion
    2028-12-31
    Enrolment
    100

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionVivax Malaria; G6PD Deficiency
    InterventionPatients with G6PD enzyme activities between 30 and <70% of the AMM will be treated with schizontocidal treatment plus high dose primaquine 1mg/kg/day for 7 days; Patients with G6PD enzyme activities <30% of the AMM will be treated with schizontocidal treatment plus 8 weekly primaquine (0.75mg/kg dose).
    PhasePhase 4
    Registry statusRecruiting

  • A Revised Tafenoquine Dose to Improve Radical Cure for Vivax Malaria

    NCT06148792 · start 2024-05-10

    Registered record
    Registry ID
    NCT06148792
    Conditions
    Vivax Malaria
    Interventions
    Tafenoquine; Primaquine
    Study type
    INTERVENTIONAL
    Phase
    Phase 3
    Registry status
    Recruiting
    Start
    2024-05-10
    Completion
    2027-03-01
    Enrolment
    1,090

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionVivax Malaria
    InterventionTafenoquine; Primaquine
    PhasePhase 3
    Registry statusRecruiting

  • Assessing the Feasibility of Combining Dihydroartemisinin Piperaquine and Primaquine for Malaria Mass Drug Administration in High Endemic Communities in the Eastern Region of Ghana

    NCT07389057 · start 2023-11-01

    Registered record
    Registry ID
    NCT07389057
    Conditions
    Malaria Asymptomatic Parasitaemia; Malaria Falciparum; Malaria Infection; Malaria Transmission
    Interventions
    DHAP; Single low dose PQ
    Study type
    INTERVENTIONAL
    Phase
    Not applicable
    Registry status
    Recruiting
    Start
    2023-11-01
    Completion
    2026-11-30
    Enrolment
    9,000

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria Asymptomatic Parasitaemia; Malaria Falciparum; Malaria Infection; Malaria Transmission
    InterventionDHAP; Single low dose PQ
    PhaseNot applicable
    Registry statusRecruiting

  • Radical Cure (RC) With Tafenoquine or Primaquine After Semi-quantitative G6PD Testing: A Feasibility Study in Peru

    NCT05361486 · start 2023-08-28

    Registered record
    Registry ID
    NCT05361486
    Conditions
    Malaria, Vivax
    Interventions
    Tafenoquine (TQ)
    Study type
    OBSERVATIONAL
    Phase
    Not recorded
    Registry status
    Completed
    Start
    2023-08-28
    Completion
    2024-12-31
    Enrolment
    187

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria, Vivax
    InterventionTafenoquine (TQ)
    PhaseNot recorded
    Registry statusCompleted

  • Safety and Immunogenicity of the Malaria Vaccine, R21/MatrixM, in Healthy Thai Adults

    NCT05252845 · start 2023-01-04

    Registered record
    Registry ID
    NCT05252845
    Conditions
    Malaria,Falciparum
    Interventions
    R21/Matrix-M vaccination; DHA-PIP; PQ
    Study type
    INTERVENTIONAL
    Phase
    Phase 2
    Registry status
    Completed
    Start
    2023-01-04
    Completion
    2023-09-18
    Enrolment
    127

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria,Falciparum
    InterventionR21/Matrix-M vaccination; DHA-PIP; PQ
    PhasePhase 2
    Registry statusCompleted

  • Momordica Charantia and Dihydroartemisinin-piperaquined-primaquine for Uncomplicated Plasmodium Falciparum Malaria Patients in Southwest Sumba Regency

    NCT05829187 · start 2022-11-01

    Registered record
    Registry ID
    NCT05829187
    Conditions
    Uncomplicated Plasmodium Falciparum
    Interventions
    Dihydroartemisinin; Piperaquine; Primaquine; Momordica Charantia Extract
    Study type
    INTERVENTIONAL
    Phase
    Phase 2
    Registry status
    Completed
    Start
    2022-11-01
    Completion
    2022-12-31
    Enrolment
    36

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionUncomplicated Plasmodium Falciparum
    InterventionDihydroartemisinin; Piperaquine; Primaquine; Momordica Charantia Extract
    PhasePhase 2
    Registry statusCompleted

  • Radical CUREfor MAlaria Among Highly Mobile and Hard-to-reach Populations in the Guyanese Shield

    NCT05540470 · start 2022-09-12

    Registered record
    Registry ID
    NCT05540470
    Conditions
    Malaria, Vivax
    Interventions
    PART; Malakit; CROSS-SECTIONAL PRE- AND POST-INTERVENTION SURVEYS; QUALITATIVE STUDY
    Study type
    INTERVENTIONAL
    Phase
    Not applicable
    Registry status
    Completed
    Start
    2022-09-12
    Completion
    2025-04-25
    Enrolment
    1,991

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria, Vivax
    InterventionPART; Malakit; CROSS-SECTIONAL PRE- AND POST-INTERVENTION SURVEYS; QUALITATIVE STUDY
    PhaseNot applicable
    Registry statusCompleted

  • Controlled Human Malaria Infection Transmission Model - Phase A

    NCT04280692 · start 2022-08-22

    Registered record
    Registry ID
    NCT04280692
    Conditions
    Malaria,Falciparum
    Interventions
    PfSPZ Challenge; Sulfadoxine-Pyrimethamine; Piperaquine; Artemether lumefantrine; Primaquine
    Study type
    INTERVENTIONAL
    Phase
    Phase 1 / Phase 2
    Registry status
    Suspended
    Start
    2022-08-22
    Completion
    2026-08
    Enrolment
    44

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria,Falciparum
    InterventionPfSPZ Challenge; Sulfadoxine-Pyrimethamine; Piperaquine; Artemether lumefantrine +1 more
    PhasePhase 1 / Phase 2
    Registry statusSuspended

  • Operational Feasibility of Appropriate Plasmodium Vivax Radical Cure After G6PD Testing in Thailand

    NCT05753150 · start 2022-05-23

    Registered record
    Registry ID
    NCT05753150
    Conditions
    Malaria, Vivax; G6PD Deficiency
    Interventions
    Tafenoquine; Primaquine; Primaquine
    Study type
    OBSERVATIONAL
    Phase
    Not recorded
    Registry status
    Completed
    Start
    2022-05-23
    Completion
    2023-10-01
    Enrolment
    187

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria, Vivax; G6PD Deficiency
    InterventionTafenoquine; Primaquine; Primaquine
    PhaseNot recorded
    Registry statusCompleted

  • Single Low Dose Tafenoquine to Reduce P. Falciparum Transmission in Mali (NECTAR2)

    NCT04609098 · start 2020-10-29

    Registered record
    Registry ID
    NCT04609098
    Conditions
    Malaria, Falciparum
    Interventions
    Dihydroartemisinin/Piperaquine; Tafenoquine 100mg [Arakoda]
    Study type
    INTERVENTIONAL
    Phase
    Phase 2
    Registry status
    Completed
    Start
    2020-10-29
    Completion
    2020-12-23
    Enrolment
    80

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria, Falciparum
    InterventionDihydroartemisinin/Piperaquine; Tafenoquine 100mg [Arakoda]
    PhasePhase 2
    Registry statusCompleted

  • Primaquine Enantiomers in G6PD Deficient Human Volunteers

    NCT04073953 · start 2020-09-01

    Registered record
    Registry ID
    NCT04073953
    Conditions
    G6PD Deficiency
    Interventions
    RPQ; SPQ; Placebo
    Study type
    INTERVENTIONAL
    Phase
    Phase 1
    Registry status
    Completed
    Start
    2020-09-01
    Completion
    2023-09-01
    Enrolment
    18

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionG6PD Deficiency
    InterventionRPQ; SPQ; Placebo
    PhasePhase 1
    Registry statusCompleted

  • Efficacy of Focal Primaquine Mass Administration for Eliminating Plasmodium Vivax Malaria in Northern Myanmar

    NCT06392152 · start 2019-07-01

    Registered record
    Registry ID
    NCT06392152
    Conditions
    Malaria; Mass Drug Administration; Myanmar; Plasmodium Vivax; Primaquine
    Interventions
    Focal Mass Drug Administration with Primaquine
    Study type
    INTERVENTIONAL
    Phase
    Not applicable
    Registry status
    Unknown
    Start
    2019-07-01
    Completion
    2024-12-31
    Enrolment
    1,208

    As stored from ClinicalTrials.gov. Registration describes a study; it does not mean the study worked.

    ConditionMalaria; Mass Drug Administration; Myanmar; Plasmodium Vivax +1 more
    InterventionFocal Mass Drug Administration with Primaquine
    PhaseNot applicable
    Registry statusUnknown