Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)

Abstract Background Credelio Quattro (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) is a novel endectocide for monthly oral administration in dogs. The safety of Credelio Quattro was investigated in dogs with pre-existing patent heartworm (Dirofilaria immitis) infections. Heart...

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Main Authors: Kari L. Riggs, Deanna Haney, Scott Wiseman
Format: Article
Language:English
Published: BMC 2025-04-01
Series:Parasites & Vectors
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Online Access:https://doi.org/10.1186/s13071-025-06732-z
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author Kari L. Riggs
Deanna Haney
Scott Wiseman
author_facet Kari L. Riggs
Deanna Haney
Scott Wiseman
author_sort Kari L. Riggs
collection DOAJ
description Abstract Background Credelio Quattro (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) is a novel endectocide for monthly oral administration in dogs. The safety of Credelio Quattro was investigated in dogs with pre-existing patent heartworm (Dirofilaria immitis) infections. Heartworm preventive products are tested in heartworm-positive dogs as rapid microfilarial and adult worm death can lead to serious clinical reactions, including death. Methods This was a gender-stratified, randomized, placebo-controlled, blinded, parallel group design study. Prior to study, dogs were surgically implanted with 10 male and 10 female adult D. immitis worms (Georgia III isolate). After confirming a patent infection, dogs were randomized into three groups (placebo control, 1×, or 3× the maximum recommended labeled dose of Credelio Quattro) consisting of eight dogs each. Treatment was administered on three consecutive monthly occasions. The assessment of safety was based on body weight, physical examinations, clinical observations on the days of dosing, general health observations, microfilariae (MF) counts, and D. immitis antigen testing. On the last day of study, the heart, lungs, and pleural and peritoneal cavities were examined for adult D. immitis worms. Results Credelio Quattro was well tolerated. Emesis occurred in the 3× group only. Diarrhea was observed in all groups at various times throughout the study. Owing to the timing of events relative to dosing, emesis and diarrhea were possibly related to treatment; however, all dogs recovered quickly and without treatment. No signs of avermectin toxicity or hypersensitivity reactions were observed in any dog. Compared with control, Credelio Quattro reduced the concentration of circulating MF on study day 1 by 38.8% for the 1× group and significantly reduced MF by 73.3% for the 3× group. MF reduction remained significant for both groups at all subsequent time points. Conclusions Credelio Quattro, when administered at 1× and 3× the maximum recommended label dose, was well tolerated following three consecutive monthly administrations to heartworm-positive dogs. Although Credelio Quattro caused a rapid reduction in microfilaria counts, no adverse effects related to microfilaria reduction were observed, and there was no effect on adult worms in this study. Graphical abstract
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spelling doaj-art-dcf1b9d4d9f84911aeb4e8c721bc622c2025-08-20T02:27:50ZengBMCParasites & Vectors1756-33052025-04-011811910.1186/s13071-025-06732-zSafety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)Kari L. Riggs0Deanna Haney1Scott Wiseman2Elanco Animal HealthElanco Animal HealthElanco Animal HealthAbstract Background Credelio Quattro (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) is a novel endectocide for monthly oral administration in dogs. The safety of Credelio Quattro was investigated in dogs with pre-existing patent heartworm (Dirofilaria immitis) infections. Heartworm preventive products are tested in heartworm-positive dogs as rapid microfilarial and adult worm death can lead to serious clinical reactions, including death. Methods This was a gender-stratified, randomized, placebo-controlled, blinded, parallel group design study. Prior to study, dogs were surgically implanted with 10 male and 10 female adult D. immitis worms (Georgia III isolate). After confirming a patent infection, dogs were randomized into three groups (placebo control, 1×, or 3× the maximum recommended labeled dose of Credelio Quattro) consisting of eight dogs each. Treatment was administered on three consecutive monthly occasions. The assessment of safety was based on body weight, physical examinations, clinical observations on the days of dosing, general health observations, microfilariae (MF) counts, and D. immitis antigen testing. On the last day of study, the heart, lungs, and pleural and peritoneal cavities were examined for adult D. immitis worms. Results Credelio Quattro was well tolerated. Emesis occurred in the 3× group only. Diarrhea was observed in all groups at various times throughout the study. Owing to the timing of events relative to dosing, emesis and diarrhea were possibly related to treatment; however, all dogs recovered quickly and without treatment. No signs of avermectin toxicity or hypersensitivity reactions were observed in any dog. Compared with control, Credelio Quattro reduced the concentration of circulating MF on study day 1 by 38.8% for the 1× group and significantly reduced MF by 73.3% for the 3× group. MF reduction remained significant for both groups at all subsequent time points. Conclusions Credelio Quattro, when administered at 1× and 3× the maximum recommended label dose, was well tolerated following three consecutive monthly administrations to heartworm-positive dogs. Although Credelio Quattro caused a rapid reduction in microfilaria counts, no adverse effects related to microfilaria reduction were observed, and there was no effect on adult worms in this study. Graphical abstracthttps://doi.org/10.1186/s13071-025-06732-zCredelio QuattroLotilanerMoxidectinPraziquantelPyrantelSafety
spellingShingle Kari L. Riggs
Deanna Haney
Scott Wiseman
Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)
Parasites & Vectors
Credelio Quattro
Lotilaner
Moxidectin
Praziquantel
Pyrantel
Safety
title Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)
title_full Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)
title_fullStr Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)
title_full_unstemmed Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)
title_short Safety of Credelio Quattro™ (lotilaner, moxidectin, praziquantel, and pyrantel chewable tablets) in dogs infected with adult heartworms (Dirofilaria immitis)
title_sort safety of credelio quattro™ lotilaner moxidectin praziquantel and pyrantel chewable tablets in dogs infected with adult heartworms dirofilaria immitis
topic Credelio Quattro
Lotilaner
Moxidectin
Praziquantel
Pyrantel
Safety
url https://doi.org/10.1186/s13071-025-06732-z
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