Abstract: International Journal of Antimicrobial Agents 57 (2021) 106236
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International Journal of Antimicrobial Agents
journal homepage: www.elsevier.com/locate/ijantimicag
Letter to the Editor
Safety profile of hydroxychloroquine and azithromycin
combined treatment in COVID-19 patients ✩
Declaration of Competing Interest
The authors declare no competing interests.
We agree with colleagues that the hydroxychloroquineazythromycin (HCQ-AZ) combination may potentially lead to drugdrug interactions [1]. Given that both drugs are known to have
potential cardiotoxicity, we paid a rigorous attention to avoiding HCQ-AZ in patients with cardiac diseases, abnormal EKG,
dyskalemia or the routine use of other interacting medications. The
systematic pre-therapy workup included serum electrolyte analysis, and an electrocardiogram with corrected QT measurement
(Bazett’s formula). Close serum electrolyte analysis monitoring was
performed in patients with low serum potassium levels at baseline. An electrocardiogram was routinely performed 48 hours after the start of treatment. Treatment with HCQ was discontinued
when the corrected QT interval (QTc, Bazett’s formula) was>500ms
and the risk-benefit ratio of HCQ+AZ treatment was estimated by
the infectious disease specialist and agreed with the cardiologist,
to be between 460 and 500ms. The indications for this control ECG
were restricted after an initial workup in 848 ECG from 424 patients (at day 0 and day 2 for each patient), showing that all contraindicative repolarization abnormalities had been detected on the
first ECG [2]. Among 3,737 COVID-19 patients diagnosed at our institute in March-April 2020, 88 (2.4%) had cardiac contraindications
to combination therapy, 45 (1.2%) patients were taking a drug with
a potential risk of interactions with combination therapy and 10
(0.3%) had hypo or hyperkalaemia [3]. A total of 3,119 patients received HCQ-AZ for at least three days. QTc prolongation (>60 ms)
was observed in 25 patients (0.67%), resulting in discontinuation of
treatment in 12 cases, including three cases with QTc> 500 ms. No
cases of torsade de pointe or sudden death were observed, including in the 9.5% of patients over 65 years of age.
Our current observations and practices illustrate the efficacy of
this risk management procedures associated with the prescription
of HCQ-AZ, which presents an excellent safety profile in COVID-19
patients, including elderly patients [4].
We agree that doxycycline has shown in vitro effect on SARSCoV-2 [5]. However, synergistic between doxycycline and hydroxychloroquine in vitro effect has not been investigated so far, unlike
azithromycin. Therefore, the combination of HCQ and doxycycline
should only be proposed for patients with a contraindication to the
HCQ-AZ regimen, independently of age.
Funding
No funding sources.
Ethical approval
Not applicable.
References
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[2] Million M, Lagier JC, Gautret P, Colson P, Fournier PE, Amrane S, et al. Early
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[3] Lagier JC, Million M, Gautret P, Colson P, Cortaredona S, Giraud-Gatineau A,
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