Use of charcoal hemoperfusion and hemodialysis in the treatment of methotrexate toxicosis in a dog

Nephrology in Veterinary Medicine

Veterinary nephrology is a specialized field of veterinary medicine providing a high level of care for animals with all types of kidney disease. Veterinarians complete extensive training to become board-certified in veterinary nephrology-urology. Companion animal nephrology is the most advanced field; however, all species are afflicted by a variety of renal disorders. Most naturally occurring animal kidney diseases have similar disorders found in people; where veterinary research is lacking, clinical management is often modified from standard of care in people. Veterinarians have become adept at scaling down procedures to safely perform them on dogs and cats weighing only a few kilograms. Advanced diagnostics (renal biopsy, cystoscopy, fluoroscopic studies, etc. ) and therapeutics (renal replacement therapy, interventional endourology, etc. ) are commonly performed within the practice of veterinary nephrology-urology. Collaboration between veterinary and human nephrologists may advance both disciplines and improve care for people and animals alike.

Extracorporeal Treatment for Methotrexate Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

Methotrexate is used in the treatment of many malignancies, rheumatological diseases, and inflammatory bowel disease. Toxicity from use is associated with severe morbidity and mortality. Rescue treatments include intravenous hydration, folinic acid, and, in some centers, glucarpidase. We conducted systematic reviews of the literature following published EXtracorporeal TReatments In Poisoning (EXTRIP) methods to determine the utility of extracorporeal treatments in the management of methotrexate toxicity. The quality of the evidence and the strength of recommendations (either "strong" or "weak/conditional") were graded according to the GRADE approach. A formal voting process using a modified Delphi method assessed the level of agreement between panelists on the final recommendations. A total of 92 articles met inclusion criteria. Toxicokinetic data were available on 90 patients (89 with impaired kidney function). Methotrexate was considered to be moderately dialyzable by intermittent hemodialysis. Data were available for clinical analysis on 109 patients (high-dose methotrexate [>0.5 g/m2]: 91 patients; low-dose [≤0.5 g/m2]: 18). Overall mortality in these publications was 19.5% and 26.7% in those with high-dose and low-dose methotrexate-related toxicity, respectively. Although one observational study reported lower mortality in patients treated with glucarpidase compared with those treated with hemodialysis, there were important limitations in the study. For patients with severe methotrexate toxicity receiving standard care, the EXTRIP workgroup: (1) suggested against extracorporeal treatments when glucarpidase is not administered; (2) recommended against extracorporeal treatments when glucarpidase is administered; and (3) recommended against extracorporeal treatments instead of administering glucarpidase. The quality of evidence for these recommendations was very low. Rationales for these recommendations included: (1) extracorporeal treatments mainly remove drugs in the intravascular compartment, whereas methotrexate rapidly distributes into cells; (2) extracorporeal treatments remove folinic acid; (3) in rare cases where fast removal of methotrexate is required, glucarpidase will outperform any extracorporeal treatment; and (4) extracorporeal treatments do not appear to reduce the incidence and magnitude of methotrexate toxicity.

Extracorporeal blood purification in acutely intoxicated veterinary patients: A multicenter retrospective study (2011-2018): 54 cases

OBJECTIVE

To investigate the clinical outcome and complications associated with extracorporeal blood purification (EBP) using either hemodialysis (HD), hemodialysis and hemoperfusion (HD + HP), or therapeutic plasma exchange (TPE) for the management of acute toxin ingestion in small animals.

DESIGN

Retrospective, multicenter study from January 2011 to July 2018.

SETTING

One university teaching hospital and one private specialty hospital.

ANIMALS

Fifty-one dogs and 3 cats with a history of acute toxin exposure that could lead to severe morbidity and mortality, managed with different EBP techniques.

MAIN RESULTS

Nonsteroidal anti-inflammatory drugs (38/54, 52%), baclofen (8/54, 15%), and ethylene glycol (7/54, 13%) were the most common toxicities treated with EBP. Membrane-based TPE was used most commonly (22/54, 40.7%), followed by HD (17/54, 31.5%) and then HD + HP (15/54, 27.8%). There was an 83.3% (45/54) overall survival, with 88.9% (8/9) of nonsurvivors having clinical signs prior to therapy. One third (18/54) of the patients never developed clinical signs of toxicity. Treatment complications occurred in 44.4% (24/54) of the animals, although only 18.5% (10/54) of these complications, such as mild hypotension, thrombocytopenia secondary to the HP cartridge, facial swelling after plasma transfusion for TPE, bleeding from catheter size secondary to heparinization, or clotting of the system, could be attributed to the EBP treatment. None of the nonsurvivors died because of EBP complications.

CONCLUSIONS

Early initiation of EBP therapy might be considered as an alternative route of decontamination in severe acute toxicities with high potential for significant morbidity and mortality. The survival rate in small animals undergoing EBP is high despite exposure to potential lethal doses of toxins, and survival appears to be more likely if clinical signs of toxicity are not present at the time of EBP. Continued research is warranted with randomized controlled clinical trials to further evaluate the clinical efficacy and benefit of EBP.

Toxicity, outcome, and management of anthracycline overdoses in 16 dogs

Background

Despite multiple reports of chemotherapy overdoses (ODs) in human and veterinary medicine, anthracycline ODs have been described infrequently.

Hypothesis/Objectives

Describe toxicities, treatments, and overall outcome after anthracycline OD in dogs.

Animals

Twelve mitoxantrone (MTX) and 4 doxorubicin (DOX) ODs were evaluated.

Methods

Multicenter retrospective analysis. The American College of Veterinary Internal Medicine oncology and internal medicine listservs were solicited for cases in which a chemotherapy OD occurred.

Results

Sixteen anthracycline cases were collected. Anthracycline ODs occurred because of an error in chemotherapy preparation (n = 9), or dose miscalculation (n = 7). The overall median OD was 1.9× (range, 1.4‐10×) the prescribed amount. Most ODs were identified immediately after drug administration (n = 11), and the majority of patients were hospitalized on supportive care (n = 11) for an average of 8 days (range, 3‐34 days). Adverse events after the OD included neutropenia (94%), thrombocytopenia (88%), anemia (63%), diarrhea (63%), anorexia (56%), vomiting (38%), lethargy (31%), and nausea (25%). Two patients did not survive the OD. High grade neutropenia was common and did not appear to be mitigated by the administration of filgrastim.

Conclusions and Clinical Importance

All patients received supportive care after identifying the OD and death was uncommon. Further evaluation is needed to determine ideal therapeutic guidelines anthracycline OD.

A Retrospective Evaluation of Chemotherapy Overdoses in Dogs and Cats

Chemotherapy overdoses (ODs) are severe complications that can occur following the use of antineoplastics. However, little is known about chemotherapy ODs in veterinary medicine. The goals of this retrospective study were to report the occurrence, type, and cause of known chemotherapy ODs in companion animal medicine. The American College of Veterinary Internal Medicine oncology and internal medicine listservs were solicited for chemotherapy OD cases in dogs and cats. An OD was defined as administration of a chemotherapy dose 10% higher than intended, or at a shorter interval than planned. Twelve non-anthracycline ODs in 11 dogs, and 3 cat ODs, were collected. Overdoses in dogs included carboplatin, cyclophosphamide, L-asparaginase, lomustine, mustargen, vincristine, and vinorelbine. The cat ODs included doxorubicin and vincristine. In dogs, the median OD was 2.1x (range: 1.2–10x) the intended dose. All dogs survived the OD and developed a variety of gastrointestinal and hematologic toxicities of varying grades. Both cats with a 2.4x vincristine OD died despite supportive care. The cat who received a 2x OD of doxorubicin survived the event, experiencing Veterinary Cooperative Oncology Group–common terminology criteria for adverse events (VCOG) grade I thrombocytopenia and anemia, and VCOG grade II neutropenia. Chemotherapy ODs appear to be rare in veterinary medicine and are typically 2–3xs the intended dose. Clinical effects include VCOG grade I and II gastrointestinal distress and VCOG grade III and IV hematologic effects. With appropriate supportive care, most patients will survive the event. Life-threatening events are more common in cats following vincristine ODs.