Metronomic chemotherapy (MC) represents an emerging strategy in veterinary oncology which involves the continuous or regularly scheduled administration of low-dose chemotherapeutic agents. Unlike conventional protocols known as maximum tolerated dose chemotherapy (MTDC), MC aims to inhibit tumor angiogenesis, stimulate antitumor immune responses, and delay or prevent the emergence of drug resistance. This review is structured into three key sections: the mechanisms of action of MC; its clinical indications in dogs and cats, particularly for advanced or treatment-resistant cancers; and reported outcomes regarding efficacy, safety, and tolerability. Additionally, we explore the growing interest in combining MC with other therapies, as well as the challenges and future directions for optimizing its use. Current evidence suggests that MC is a promising and well-tolerated option for managing various malignancies—such as carcinomas, sarcomas, and hemangiosarcomas—especially in patients who are not candidates for MTDC.

Objective: To evaluate whether intravenous administration of dexmedetomidine alters the electrocardiographic parameters of healthy dogs. Animals: 22 healthy dogs. Study Design: prospective blind clinical trial. Materials and Methods: The dogs underwent electrocardiographic monitoring at two moments: baseline moment (MB), subjected to tranquilization with butorphanol (0.25 mg/kg/IM), and dexmedetomidine moment (MDEX), after 10 min of intravenous administration of dexmedetomidine (bolus of 2 μg/kg, in 2 minutes, followed by continuous infusion at a rate of 2 μg/kg/hour). Results: After intravenous administration of dexmedetomidine, sinus bradycardia predominated. Regarding electrocardiographic parameters, there was a significant increase in the duration of the P wave (44; 51 ms), QRS complex (62; 67 ms), PR interval (95; 126 ms), and QT interval (207; 252 ms) and reduction in the QTc interval (249; 226 ms), without significant change in systolic, mean, and diastolic blood pressure. Conclusion: Intravenous administration of dexmedetomidine in healthy dogs results in increased parasympathetic tone with significant reduction in heart rate and increased conduction time of electrical impulses in the myocardium.

Introduction: Propofol is an intravenous anesthetic administered as a bolus or continuous infusion during anesthetic induction and maintenance. Its pharmacokinetic characteristics include hepatic and extrahepatic metabolism with a rapid onset of action and short duration, which provides a smooth anesthetic induction without excitatory effects.Objective: To evaluate whether the isolated use of propofol in anesthetic induction in dogs changes the hemodynamic variables assessed via echocardiography.Study Design: Prospective clinical study.Animals: Twelve healthy dogs.Methods: The dogs were induced with propofol (dose/effect) at 3 mg/kg/minute, and echocardiographic evaluations were performed immediately before anesthetic induction (MB) and immediately after its interruption (MI), at the end of the supply of the anesthetic agent.Results: A significant reduction was observed between the values of the following hemodynamic variables: Ejection Fraction (EF%), which varied from 70% to 65% (p = 0.011) between moments, and the Doppler Ejection Index (DEI), which ranged from 27.1 mL/beat/m² to 22.4 mL/beat/m² (p = 0.044). The heart rate (HR) and the other studied hemodynamic variables showed no significant differences between the evaluated moments.Conclusion and Clinical Relevance: Propofol was a safe anesthetic‐inducing agent, maintaining stable hemodynamic indices during anesthetic induction at the used rate.

Introduction: Lidocaine is a local anesthetic widely used in veterinary medicine and can be administered intravenously as a continuous infusion during general anesthesia. In addition to its analgesic and anti‐inflammatory properties, lidocaine has antiarrhythmic effects that may influence cardiac electrical activity during anesthetic procedures. Objective: To evaluate whether continuous intravenous infusion of lidocaine in dogs anesthetized with sevoflurane alters electrocardiographic and hemodynamic variables. Study Design: Prospective clinical study. Animals: Twenty healthy dogs. Methods: Dogs were anesthetized with sevoflurane administered via face mask, followed by orotracheal intubation and anesthetic maintenance with the same agent. After stabilization of the anesthetic plane, baseline measurements were recorded. The animals were randomly allocated into two groups: control group (CG) and lidocaine group (LG). In the LG, lidocaine was administered as an intravenous bolus (2 mg/kg) followed by continuous infusion at a rate of 100 μg/kg/min. The CG received 0.9% saline solution at equivalent volumes and infusion rates. Evaluations were performed at baseline and at 20, 40, 60, and 80 min after the start of the infusion. The variables analyzed included heart rate (HR), systolic, mean, and diastolic arterial blood pressures (SBP, MAP, and DBP, respectively), and electrocardiographic variables such as P wave duration, PR interval, QRS complex duration, QT interval, and P wave and R wave amplitudes. Results: No significant differences were observed between groups or across time points for any of the evaluated variables. Conclusion and Clinical Relevance: Continuous intravenous infusion of lidocaine at the evaluated dose did not produce significant electrocardiographic or hemodynamic alterations in dogs anesthetized with sevoflurane under the conditions of this study, suggesting no detectable impact on cardiovascular function in this experimental setting.

Objective: To investigate whether there is a positive correlation between vertebral left atrial size (VLAS) and echocardiographic variables—left atrium‐to‐aorta ratio (LA/Ao), left ventricular fractional shortening (FS), left ventricular internal diameter in diastole normalized to body weight (LVIDdn), and left ventricular early filling velocity (E‐wave)—and the Mitral INsufficiency Echocardiographic (MINE) echocardiographic score. Study Design: Prospective randomized blinded study. Animals: A total of 26 dogs. Methods: Dogs diagnosed with MVD participated in the study. All patients underwent radiographic and echocardiographic evaluation. Results: A high correlation strength could be observed between the left atrial enlargement predictor VLAS and the LA/Ao ratio (88%), as well as with LVIDdn (75%) and E‐wave (74%). Furthermore, a correction strength of 84% was verified between VLAS and the MINE score. The analysis of the FS variable did not demonstrate a statistically significant relationship ( p value of 0.06). Conclusions and Clinics Relevance: VLAS has a positive relationship and important correlation with the echocardiographic variables and MINE score. Associated with its higher accessibility in clinical routine is a potential diagnostic method to detect left atrial enlargement in dogs, contributing to the diagnostic conduct in DVM.