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RecruitingNCT05504057Updated Apr 3, 2026

Antihistamines, Amantadine and Evolution of COVID-19

An observational study in COVID-19, sponsored by Consorci Sanitari de Terrassa. Recruiting at 2 sites in Spain. Per ClinicalTrials.gov, last updated 2026-04-03.

Sponsored by Consorci Sanitari de Terrassa · Observational

From the registry’s dates

  • Started Mar 2020; still recruiting 6 years 8 months later.
Study type
Observational
Model
Case-control
Time perspective
Retrospective
Enrollment
140,660
Sex
All
01

Study summary

The rates of symptomatic COVID19 infection, hospital admission among COVID19 cases and survival would be quantified in patiens chronically treated with antihistamines or amantadine, with the aim of determining the role of antihistamines and amantadine in the evolution of COVID19.

Read the detailed description

BACKGROUND: According to previous reports, all 84 eldery residents in nuersing homes in Yespes (Toledo, Spain), had a 100% of positive serology for COVID-19 in June 2020, but none died nor hospitalized after receiving early treatment with antihistamines. Other case reports have suggested a protective role of amantadine, since infected patients showed a very mild COVID19 infection.

OBJECTIVES.Determine the role of antihistamines and amantadine in the evolution of COVID19.

METHODS. Describe the rate of hospitalization, ICU, survival, postcovid syndrome and thrombosis among COVID 19 cases having antihistamines and amantadine as chronic treatments.

The rates would be stratified by age groups and compared with the same age groups of the population assigned to the public free Access Terrassa Health Consortium.

02

Conditions studied

  • COVID-19

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Keywords

  • antihistamines
  • amantadine
  • hospital admissions
  • survival
03

In context

COVID-19

7,990 studies on the registry are indexed under COVID-19; 466 are open to participants now.

This study's planned enrollment of 140,660 is above the median of 268 across 3,208 observational studies indexed under COVID-19.

Browse COVID-19 studies →

Lead sponsor

Consorci Sanitari de Terrassa is the lead sponsor of 41 studies on the registry; 15 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
Child (0–17), Adult (18–64), Older adult (65+)
Sexes eligible
All
Accepts healthy volunteers
Yes
Sampling method
Non-probability sample

Study population

Population assigned to the Public and free Access Terrassa Health Consortium

Eligibility criteria

Inclusion Criteria: Patients having chronic treatment with antihistamines or amantadine -

Exclusion Criteria: None

-

05

Study design

Observational model
Case-control
Time perspective
Retrospective
Enrollment
140,660 participants (estimated)
Patient registry
No

Groups and cohorts

  • Patients with chronic treatment with antihistamines or amantadine

    The % of patients having antihistamines or amantadine as chronic treatment that suffered COVID would be compared to the population of the Terrassa Health Consortium (THC) of the same age groups.

    Drug: Antihistamine · Drug: Amantadine

  • Other population of the THC

    The % of patients of the Terrassa Health Consortium that suffered COVID19 infection of the same age groups.

Interventions

  • DrugAntihistamine

    Observation of the rate of COVID19 infection, the rate of hospitalization, the rate of survival and postcovid syndrome and thrombosis among patients previously treated with antihistamines

    Also known as: Antihistamine as crhonic treatment and COVID19 infection.

  • DrugAmantadine

    Observation of the rate of COVID19 infection, the rate of hospitalization, the rate of survival and the rate of postcovid syndrome and thrombosis among patients previously treated with amantadine

    Also known as: Amantadine as chronic treatment and COVID19 infection.

06

What researchers measure

Primary outcomes

  1. Hospital Admissions.

    Rate of Hospitalization among COVID 19 infections

    Time frame: from march 2020.

Secondary outcomes

  1. Survival

    Survival among COVID1 hospitalized cases.

    Time frame: from march 2020

  2. Symptomatic infection

    Patients suffering a symptomatic COVID19 infection within a determinate age group

    Time frame: from march 2020

  3. Postcovid syndrome

    Patients developing postcovid syndrome after COVID19 infection

    Time frame: from april 2020

  4. Thrombosis

    Patients developing thrombosis (with particular assessment of stroke, cardiac infarction, retinal vessels and pulmonary embolism)

    Time frame: from april 2020

07

Study locations

2 of 2 sites recruiting
  • Hospital de Terrassa
    Terrassa, Barcelona 08227, Spain
    Recruiting
  • Hospital of Terrassa
    Terrassa, Barcelona 08227, Spain
    Recruiting
    • Anna Puigdellívol, PhD · Contact
08

References and documents

Publications

  • Moran Blanco JI, Alvarenga Bonilla JA, Homma S, Suzuki K, Fremont-Smith P, Villar Gomez de Las Heras K. Antihistamines and azithromycin as a treatment for COVID-19 on primary health care - A retrospective observational study in elderly patients. Pulm Pharmacol Ther. 2021 Apr;67:101989. doi: 10.1016/j.pupt.2021.101989. Epub 2021 Jan 16. PubMed 33465426 ↗
  • Cortes-Borra A, Aranda-Abreu GE. Amantadine in the prevention of clinical symptoms caused by SARS-CoV-2. Pharmacol Rep. 2021 Jun;73(3):962-965. doi: 10.1007/s43440-021-00231-5. Epub 2021 Feb 18. PubMed 33604795 ↗
  • Puigdellivol-Sanchez A, Juanes-Gonzalez M, Calderon-Valdiviezo A, Losa-Puig H, Valls-Foix R, Gonzalez-Salvador M, Lozano-Paz C, Vidal-Alaball J. COVID-19 in Relation to Chronic Antihistamine Prescription. Microorganisms. 2024 Dec 13;12(12):2589. doi: 10.3390/microorganisms12122589. PubMed 39770791 ↗
  • Puigdellivol-Sanchez A, Juanes-Gonzalez M, Calderon-Valdiviezo A, Valls-Foix R, Gonzalez-Salvador M, Lozano-Paz C, Vidal-Alaball J. COVID-19 in Relation to Polypharmacy and Immunization (2020-2024). Viruses. 2024 Sep 27;16(10):1533. doi: 10.3390/v16101533. PubMed 39459868 ↗
  • Puigdellivol-Sanchez A, Arevalo-Genicio A, Garcia-Arque MC, Gragea-Nocete M, Lozano-Paz C, Moro-Casasola V, Perez-Diaz C, Valls-Foix R, Roca-Puig R, Llistosella M. Long COVID and Reduced Thrombosis in Antihistamine-Treated Patients: An Observational Study in the Metropolitan Area of Barcelona. Viruses. 2026 Feb 2;18(2):197. doi: 10.3390/v18020197. PubMed 41754542 ↗

Individual participant data

Plan to share: Undecided — Once the papers related to the study are published, a statement will be included offering data when contacting with the authors.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Ran from Mar 2020 to primary completion in Jan 2025, 58 months.

How these figures are worked out, and which studies are left out of them.

Registered
Aug 15, 2022
First posted
Aug 17, 2022
StartActual
Mar 1, 2020
Primary completionActual
Jan 19, 2025
CompletionEst.
Feb 24, 2028
Last update
Apr 3, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Apr 3, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05504057
Lead sponsor
Consorci Sanitari de Terrassa
Collaborators
Institut Català de la Salut
Responsible party
Anna Puigdellívol-Sánchez (Principal Investigator, Consorci Sanitari de Terrassa) — Principal investigator
First posted
Aug 17, 2022
Start date
Mar 1, 2020
Primary completion
Jan 19, 2025
Completion
Feb 24, 2028 (estimated)
Last update
Apr 3, 2026

Study contacts

Anna Puigdellivol, Ph.D
Contact
apuigdellivol@cst.cat
34-93-5884555
Anna Puigdellívol, PhD
principal investigator · Terrassa Health Consortium

Oversight

Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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