Dr. Brentnall studies the use of oxytetracycline, an antibiotic, and carprofen, a pain reliever, specifically in calves. He investigates how these medications are processed by the body, how they interact with each other, and their effectiveness against infections caused by a specific bacteria, Mannheimia haemolytica. His research is crucial for veterinarians and farmers, as it sheds light on the best practices for administering these drugs to ensure the health and well-being of calves.
Key findings
Oxytetracycline can remain effective against bacteria for about 48 hours, but it has limited effectiveness against Mannheimia haemolytica at recommended doses, which may affect treatment outcomes.
Administering oxytetracycline alongside carprofen did not significantly alter how carprofen is absorbed or eliminated, suggesting veterinarians can safely use both without dosage adjustments.
The S(+) form of carprofen is over 200 times more effective than the R(-) form in inhibiting COX-2 enzymes in calves, indicating the importance of choosing the right formulation for pain management.
Frequently asked questions
Does Dr. Brentnall study antibiotics?
Yes, he conducts research on oxytetracycline, an antibiotic used in calves.
What treatments has Dr. Brentnall researched?
He has researched the use of oxytetracycline and carprofen for treating infections and pain in calves.
Is Dr. Brentnall's work relevant to veterinarians?
Absolutely, his findings help veterinarians make informed decisions about drug use in treating calves.
What specific condition is addressed in Dr. Brentnall's work?
His research addresses bacterial infections in calves, particularly those caused by Mannheimia haemolytica.
Can carprofen and oxytetracycline be used together in calves?
Yes, his studies show that these medications can be safely administered together without the need for dosage changes.
Publications in plain English
Influence of oxytetracycline on carprofen pharmacodynamics and pharmacokinetics in calves.
2013
Journal of veterinary pharmacology and therapeutics
Brentnall C, Cheng Z, McKellar QA, Lees P
Plain English This study looked at how the antibiotic oxytetracycline affects the way carprofen, a pain relief medication, works and is processed in calves. The researchers found that giving oxytetracycline along with carprofen did not significantly change how the body absorbed or eliminated carprofen, although there was a slight decrease in the blood levels of one version (S(+) form) of carprofen. This matters because it means that veterinarians can safely use both medications together without needing to adjust carprofen's dosage.
Who this helps: This helps veterinarians treating calves for pain and infections.
Pharmacokinetic-pharmacodynamic integration and modelling of oxytetracycline administered alone and in combination with carprofen in calves.
2013
Research in veterinary science
Brentnall C, Cheng Z, McKellar QA, Lees P
Plain English This study looked at how oxytetracycline, an antibiotic, works when given alone and with another drug, carprofen, in healthy calves. Researchers found that there weren't significant differences in how the body processed oxytetracycline whether it was given alone or with carprofen. However, while high levels of the drug can kill bacteria for about 48 hours, it showed limited direct effectiveness against a specific strain of bacteria called Mannheimia haemolytica, suggesting that oxytetracycline may work through other ways besides just killing bacteria.
Who this helps: This information is useful for veterinarians and farmers caring for calves.
Potency and selectivity of carprofen enantiomers for inhibition of bovine cyclooxygenase in whole blood assays.
2012
Research in veterinary science
Brentnall C, Cheng Z, McKellar QA, Lees P
Plain English This study looked at how two forms of the drug carprofen affect certain enzymes (COX-1 and COX-2) in calves' blood. It found that the S(+) form of carprofen is much more effective at inhibiting COX-2 than the R(-) form, with an effectiveness ratio of over 200 times greater at certain levels of drug concentration. This matters because understanding which form of carprofen works better can help improve pain management and safety for calves receiving this medication.
Who this helps: This helps veterinarians treating calves for pain.
Pharmacodynamics of oxytetracycline administered alone and in combination with carprofen in calves.
2012
The Veterinary record
Brentnall C, Cheng Z, McKellar QA, Lees P
Plain English The study examined how effective the antibiotic oxytetracycline is against a specific bacteria, Mannheimia haemolytica, in calves, both alone and when given with the pain reliever carprofen. Researchers found that the antibiotic struggled to inhibit the growth of the bacteria in real body fluids like blood and tissue, even though it appeared effective in lab tests. This is important because it suggests that oxytetracycline may not work as well as expected in treating infections in calves at the recommended doses.
Who this helps: This helps veterinarians and farmers caring for calves by highlighting potential limitations in using oxytetracycline for infections.