Favipiravir does not appear to be a major teratogen: Case series from Türkiye

INTRODUCTION

Favipiravir has gained attention during the Coronavirus Disease-2019 pandemic due to its potential antiviral effect against Severe Acute Respiratory Syndrome Coronavirus-2. Favipiravir has been identified as a teratogen in animal studies, but there is limited human data. We aimed to evaluate the pregnancy outcomes of women exposed to favipiravir during the pandemic.

MATERIAL AND METHODS

Pregnant women who were exposed to favipiravir and applied to Marmara University School of Medicine Medical Pharmacology Outpatient Clinic Teratology Information Service between December 2020-September 2021 are included in the study. The demographic information, medical and obstetric histories of patients were acquired during admission, the outcomes of the pregnancies and the characteristics of the infants were gathered by regular phone calls. The infants whose parents consented were evaluated by a pediatrician for general well-being and congenital anomalies.

RESULTS

22 pregnant women were included in this study. 81.8 % received the recommended favipiravir dose (8000 mg in 5 days), in the first trimester. Two patients were lost to follow-up, there was one elective termination and 19 live births. Congenital anomalies were found in 2 infants, one of whom had 9q34 duplication syndrome. Except for these, all newborns examined by the pediatrician were healthy.

DISCUSSION

Within a limited case series, a subset of the infants exposed to favipiravir prenatally were followed up to 1 year of age. Two infants exhibited congenital malformations that cannot be directly linked to favipiravir due to confounding variables. Considering the limited data published, favipiravir does not appear to be a major teratogen.

Duration of Ciprofloxacin Use Is Important in the Development of Abdominal Aortic Aneurysm in a Rat Model

BACKGROUND

Recent findings suggest that fluoroquinolones, most prescribed antibiotic to treat various infections, have increased abdominal aortic aneurysm formation. We aimed to investigate the relation of the development of abdominal aortic aneurysm and the duration of ciprofloxacin use.

METHODS

Male Sprague-Dawley rats were divided into 2 groups to administer saline to the control groups and CaCl2 to the aneurysm groups. These groups were then divided into 3 subgroups: intraperitoneal saline, ciprofloxacin for 2 weeks, and ciprofloxacin for 4 weeks. At the end of 4 weeks, the diameter of abdominal aorta was determined by ultrasonography and animals were sacrificed to obtain abdominal aorta specimens. Elastic fiber fracture, tunica media layer thickness, and aortic tissue damage were evaluated histologically.

RESULTS

Aortic diameter of control-saline (2.15 mm ± 0.06), control-2 weeks (2.25 mm ± 0.06), and control-4 weeks (3.31 mm ± 0.09) ciprofloxacin groups was significantly different (P < .0001). Also, aortic diameter of aneurysm-saline (2.07mm ± 0.02), aneurysm-2 weeks ciprofloxacin (3.33 mm ± 0.64), and aneurysm-4 weeks ciprofloxacin (8.55 mm ± 1.70) groups showed significant increase in aortic diameter with increasing duration of ciprofloxacin use (P < .01). A significant difference was found between the control-saline (0.00 ± 0.00), control-2 weeks (1.50 ± 0.33), and control-4 weeks ciprofloxacin groups (1.57 ± 0.20) in the histological aneurysm scores (P < .001). Aortic tunica media thickness did not change between control-saline and control-ciprofloxaci n groups (P > .05).

CONCLUSION

The study showed that ciprofloxacin caused injury in the aortic wall but not a significant change in the thickness of the aortic tunica media layer. The duration of ciprofloxacin use was important in the development of aneurysm and aneurysm severity.

Pharmacokinetic characterization of favipiravir in patients with COVID-19

This prospective observational study describes the pharmacokinetic characteristics of favipiravir in adult patients hospitalized for mild to moderate COVID-19 with a positive RT-PCR test. Favipiravir was administered for 5 days, with a loading dose of 3200 mg and a maintenance dose of 1200 mg/day. Serial blood samples were collected on Day-2 and Day-4 of the therapy. Laboratory findings of the patients (n=21) and in-hospital mortality were recorded. Favipiravir concentrations exhibited substantial variability and a significant decrease during the treatment of COVID-19. The median favipiravir trough concentration (C_0-trough ) on Day-2 was 21.26 (IQR, 8.37-30.78) μg/mL whereas it decreased significantly to 1.61 (IQR, 0.00-6.41) μg/mL on Day-4, the area under the concentration versus time curve decreased by 68.5%. Day-2-C_0-trough of female patients was higher than male patients. Our findings indicate that favipiravir concentrations show significant variability during the treatment of COVID-19 and therapeutic drug monitoring may be necessary to maintain targeted concentrations.