Diffusion of fluoroquinolones into equine fetal fluids did not induce fetal lesions after enrofloxacin treatment in early gestation. (November 2019)

• Record Type: Journal Article
• Authors: Ellerbrock, R.E.; Canisso, I.F.; Podico, G.; Roady, P.J.; Uhl, E.; Lima, F.S.; Li, Z.
• Is Part Of: Veterinary journal. Volume 253(2019)
• Publication Date: 2019-11
• Subjects: Antibiotic -- Ciprofloxacin -- Fetal -- Toxicity -- Horse -- Pregnancy; Veterinary medicine -- Periodicals; 636
• DOI: 10.1016/j.tvjl.2019.105376
• Languages: English
• ISSNs: 1090-0233

Abstract

Highlights: Enrofloxacin and ciprofloxacin crossed the equine placenta at 60 days gestation. Fourteen days of enrofloxacin treatment did not cause gross or microscopic lesions in the 60-day-old fetus. Enrofloxacin exposure did not change allantoic or amniotic fluid chemistries in early equine gestation. Abstract: While recent work demonstrated that enrofloxacin and ciprofloxacin reach the fetoplacental unit without causing obvious lesions in the 9-month-old equine fetus or resulting foal, many practitioners still hesitate to prescribe a fluoroquinolone during pregnancy. Since early gestation is a critical time for fetal skeletal development, if fluoroquinolones are chondrotoxic to the fetus at any point during gestation, this period would be important. The aim of this study was to assess the effects of 2 weeks' exposure to enrofloxacin on the equine fetus between 46 and 60 days gestation. Twelve pregnancies from nine healthy mares were allocated into two groups: untreated ( n = 7), or treatment (7.5 mg/kg enrofloxacin, PO × 14 days, n = 6). Abortion was induced with prostaglandin 24 h after the last enrofloxacin dose, or on the equivalent day of gestation for untreated mares. Four of nine mares were rebred for a second cycle and were assigned to the opposite treatment to serve as their own controls. Fetal fluids from treated mares were analysed for enrofloxacin and ciprofloxacin concentrations. Fetal organs (heart, lungs, spleen, kidney, and liver) and limbs were examined histopathologically. Enrofloxacin and ciprofloxacin diffused to the fetal fluids during early gestation and did not result in detectable abnormalities in the fetus after 14 days of treatment. While current research does not determine long-term foal outcomes, enrofloxacin may be useful for select bacterial infections in pregnant mares.