Related Experiment Video
Updated: Sep 23, 2025

Comparing Objective Conjunctival Hyperemia Grading and the Ocular Surface Disease Index Score in Dry Eye Syndrome During COVID-19
Published on: May 25, 2022
Hydroxychloroquine safety in Covid-19 vs non-Covid-19 patients: analysis of differences and potential interactions
María Sainz-Gil1,2, Nieves Merino Kolly3, Verónica Velasco-González1,2,4
1Centro de Estudios sobre la Seguridad de los Medicamentos (CESME). Departamento de Biología Celular, Histología, Farmacología y Genética. Facultad de Medicina. Universidad de Valladolid, Valladolid, Spain.
Background:
The use of hydroxychloroquine (HCQ) in the first COVID-19 epidemic wave raised safety concerns.
Research Design And Methods:
Adverse reactions (ADR) suspected to be induced by HCQ and submitted to the Spanish Pharmacovigilance Database were studied. A disproportionality analysis was performed to determine adverse effects reported in non-Covid and Covid patients. To explore potential drug-drug interactions, Omega (Ω) statistics was calculated.
Results:
More severe cases were reported when used in COVID-19. Main differences in frequency were observed in hepatobiliary, skin, gastrointestinal, eye, nervous system and heart ADRs. During the COVID-19 pandemic, high disproportionality in reports was found for Torsade de Pointes/QT prolongation with a ROR (-ROR) of 132.8 (76.7); severe hepatotoxicity, 18.7 (14.7); dyslipidaemias, 12.1 (6.1); shock, 9.5 (6.9) and ischemic colitis, 8.9 (2.6). Myopathies, hemolytic disorders and suicidal behavior increased their disproportionality during the pandemic. Disproportionality was observed for neoplasms, hematopoietic cytopaenias and interstitial lung disease in the pre-COVID-19 period. Potential interactions were showed between HCQ and azithromycin, ceftriaxone, lopinavir and tocilizumab.
Conclusions:
The use of HCQ during the Covid-19 pandemic changed its ADRs reporting profile. Of particular concern during the pandemic were arrhythmias, hepatotoxicity, severe skin reactions and suicide, but not ocular disorders. Some signals identified would require more detailed analyses.
More Related Videos
Related Concept Videos
Factors Affecting Renal Clearance: Drug Distribution and Drug Interactions
One important factor is the relationship between renal clearance and the apparent volume of distribution. Renal clearance tends to be inversely proportional to the apparent volume of distribution. Drugs with an extensive distribution volume or those...
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
Nonlinear Pharmacokinetics: Dependence of Elimination Half-Life and Dose Clearance
A study on guinea pigs examined the...
Model-Independent Approaches for Pharmacokinetic Data: Noncompartmental Analysis
One important characteristic of noncompartmental analyses is that drug exposure increases proportionally with increasing doses. This...
Combined Effects of Drugs: Synergism
Such synergistic combinations...
Factors Affecting Protein-Drug Binding: Drug Interactions
Displacement interactions can have varying outcomes, ranging from toxicity to virtually...

