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Research article - Peer-reviewed, 2022

Concentration of carprofen in the milk of lactating bitches after cesarean section and during inflammatory conditions

Ferrari, Desiree; Lundgren, Sandra; Holmberg, Johanna; Edner, Anna; Ekstrand, Carl; Nyman, Gorel; Bondesson, Ulf; Hagman, Ragnvi


Pain treatment of lactating bitches is a clinically relevant, but complicated issue. Published scientific studies regarding the excretion of drugs in canine milk are scarce. When considering the risk of side effects in their offspring, lactating bitches have traditionally received very restricted analgesic and anti-inflammatory therapy. Our aim was to quantify the concentrations of carprofen in milk from lactating bitches and relate those to potential risks for the puppies. A second aim was to evaluate the impact mastitis may have on the concentration of carprofen in milk. A population of 100 bitches was enrolled in the study, among which 88 were bitches treated with carprofen after cesarean section (Group CS), eight were bitches with painful inflammatory conditions (Group I) and four were bitches with mastitis (Group M). The patients enrolled in the study received carprofen 4 mg/kg sc at day 1 followed by 2 mg/kg po every 12 h for the following 2-5 days. Owners were instructed to collect milk once a day for five days. The concentration of carprofen in the milk was quantified with ultra-performance liquid chromatography-tandem mass spectrometry. The data obtained were statistically analyzed as repeated-measures data with a mixed-model approach. Data were used to calculate the theoretical maximum total daily intake of carprofen by the puppies in order to perform a computerized simulation of the plasma concentration of carprofen in the puppies. Follow-up telephone interviews to check the status of the enrolled bitches and their litters occurred at one week and three-six months after treatment with car-profen. The major finding of the study was that the concentration of carprofen in the milk was <700 ng/ mL from bitches undergoing CS or suffering painful conditions other than mastitis. In comparison, administration of 2 mg/kg of carprofen sc or po to adult dogs, results in mean maximal plasma con-centrations of 19480 +/- 5420 ng/mL (mean +/- SD). Moreover, data suggests that inflammation of the mammary gland results in a higher concentration of carprofen in milk (up to 1300 ng/mL). In the computerized simulation, the plasma concentrations of carprofen in puppies in group CS and in group I are one tenth of the concentration in adult dogs receiving carprofen at standard doses. Considering the low excretion into milk, carprofen provides an analgesic alternative to lactating bitches without mastitis.(c) 2022 Published by Elsevier Inc.


Carprofen; Dog; Lactation; Milk excretion; Mastitis; Cesarean section

Published in

2022, Volume: 181, pages: 59-68