Low-Level Lasers Efficacy ???

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Low-Level Laser Therapy in Dogs

Photobiomodulation therapy (PBMT), also known as low-level laser therapy, is gaining popularity in both human and animal rehabilitation. It uses light to stimulate photochemical processes rather than producing heat, targeting the cytochrome C oxidase in cells to accelerate electron transport and increase ATP production. This process is believed to speed up the recovery of injured tissues by reducing inflammation, edema, and pain, and promoting wound healing. 

Despite its growing use, studies, especially in veterinary medicine, show mixed results. The effectiveness of PBMT can be influenced by various factors such as dosage, skin and coat color, and the area being treated. In veterinary applications, dosages range from 3 to 10 J/cm2, but there is inconsistency in the administration of these dosages. 

PBMT's role in managing post-surgical outcomes, like in dogs undergoing tibial plateau leveling osteotomy (TPLO) for cranial cruciate ligament rupture, is of particular interest. While some studies indicate benefits like improved bone healing and pain management, others don't show significant differences. One of the challenges in TPLO surgery is the high rate of surgical site infections (SSI), which can range from 2.9% to 25.9%. Theories suggest that factors like diminished blood supply during and after surgery contribute to this risk. 

The present study focused on the effects of PBMT in dogs undergoing TPLO surgery. Parameters like C-reactive protein (CRP) levels, weight-bearing capacity, pain scores, and incidence of SSI were measured. The study found no significant differences in CRP levels, weight-bearing, or pain scores between the PBMT-treated group and the control group. However, there was a notable difference in SSI rates, with a lower occurrence in the PBMT group. 

This study suggests that while PBMT may not significantly impact factors like pain and recovery post-TPLO surgery, it could potentially reduce the risk of surgical site infections. However, the results are not definitive, and further research is needed to establish the efficacy of PBMT in clinical outcomes. The study also highlights the importance of controlled and blinded methodologies to reduce bias and variability in surgical outcomes. 

Chavez, O. A., Renberg, W., & Cernicchiaro, N. (2023). Photobiomodulation therapy in dogs undergoing TPLO after cranial cruciate ligament rupture shows promise but no statistically significant difference in a randomized trial. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.23.06.0138 

Bottom line — This study does not support use for pain but might help with infection risk.

Stopping Omeprazole Therapy in Horses

The study focused on understanding the effects of medium-term (57 days) treatment with omeprazole, a proton pump inhibitor (PPI), on horses, particularly regarding serum gastrin and chromogranin A (CgA) concentrations. It's known that long-term PPI use can lead to rebound gastric hyperacidity (RGH) due to increased gastrin production and enterochromaffin-like (ECL) cell density. 

Key findings from the study include: 

• Hypergastrinemia Development: Horses showed a rapid increase in serum gastrin levels within 7 days of starting omeprazole treatment. This increase did not continue to rise significantly over the treatment period. 

• Return to Baseline Post-Treatment: After discontinuing omeprazole, serum gastrin levels returned to baseline within 2 to 4 days. This rapid normalization contrasts with some human studies where normalization can take longer. 

• Lack of Clear Impact on Serum CgA: The study did not identify a clear change in serum CgA concentrations in response to omeprazole treatment. This suggests that the response of ECL cells to hypergastrinemia in horses might differ from that in humans and other species. 

• Potential Contribution to ESGD Recurrence: Increased serum gastrin concentrations during omeprazole treatment might contribute to short-term RGH development, potentially explaining the rapid recurrence of equine squamous gastric disease (ESGD) post-treatment. 

• Management Recommendations: The study suggests that tapering omeprazole after medium-term treatment may not be necessary in horses. Instead, management practices to decrease ESGD risk, such as reducing exercise and increasing roughage intake, should be emphasized immediately after stopping omeprazole. 

• Study Limitations: The study faced limitations like the lack of validation for the CgA ELISA kit in horses, brief periods without omeprazole treatment, and the absence of control horses. 

In conclusion, the study confirmed the rapid onset of hypergastrinemia in horses treated with omeprazole and its quick reversal post-treatment, with no clear impact on serum CgA levels. These findings suggest that immediate post-treatment management rather than tapering of omeprazole is crucial in managing ESGD risk in horses. 

Clark, B, Steel, C, Vokes, J, et al. Evaluation of the effects of medium-term (57-day) omeprazole administration and of omeprazole discontinuation on serum gastrin and serum chromogranin A concentrations in the horse. J Vet Intern Med. 2023; 37(4): 1537-1543. doi:10.1111/jvim.16795 

Bottom line — Taper for medium-term duration may not be needed.

IV Quinalones In Cats With Kidney Disease

This comprehensive study focused on the pharmacokinetics of enrofloxacin, a fluoroquinolone antibiotic, and its active metabolite ciprofloxacin in cats, particularly those with kidney dysfunction. Enrofloxacin, commonly used in veterinary medicine, is extensively metabolized by the liver into ciprofloxacin, with both components contributing to its antibacterial effects. Despite its approval only for use in dogs in the United States, enrofloxacin is often used off-label in cats, especially because it is the only injectable fluoroquinolone available in the country. 

The study adopted a population pharmacokinetic approach with sparse sampling to understand how enrofloxacin behaves in cats with naturally occurring kidney disease. This method was chosen as it allows for less frequent sampling from client-owned cats in a hospital setting. The findings showed that variations in kidney function, assessed using biomarkers like serum creatinine, BUN, and SDMA, did not significantly contribute to differences in the clearance or volume distribution of fluoroquinolones in cats. Surprisingly, only body weight significantly impacted the volume of the first compartment and its clearance. 

Moreover, the study revealed no significant differences in drug accumulation or clearance among cats grouped according to the severity of kidney dysfunction. This outcome suggests that kidney disease doesn't necessarily affect the metabolism of enrofloxacin into ciprofloxacin or the overall elimination of the drug. In contrast, prior studies in other species have indicated reduced fluoroquinolone clearance due to kidney disease. 

A notable finding was that BUN levels influenced the rate of enrofloxacin's conversion to ciprofloxacin, suggesting that cats with higher azotemia might have increased ciprofloxacin formation. However, the study also highlighted the poor utility of BUN as a biomarker for glomerular filtration rate (GFR) in cats, casting doubt on the significance of this finding. 

The study concluded that, based on the current understanding, there's no need to adjust the dosage or administration schedule of enrofloxacin in cats with kidney disease. However, it acknowledges the need for further research, especially regarding repeated doses of the medication and its effects in this specific group. Additionally, the study underlines the relevance of understanding drug pharmacokinetics in animals with various health conditions to ensure effective and safe medication practices. 

Foster, JD, Abouraya, M, Papich, MG, Muma, NA. Population pharmacokinetic analysis of enrofloxacin and its active metabolite ciprofloxacin after intravenous injection to cats with reduced kidney function. J Vet Intern Med. 2023; 37(6): 2230-2240. doi:10.1111/jvim.16866

Bottom line — No need to adjust the dose for cats with kidney disease.

Just putting things in perspective …