Pyrantel pamoate / Praziquantel: what the FDA reviewed for dog products
1 Freedom of Information summary from the FDA Center for Veterinary Medicine for products containing Pyrantel pamoate / Praziquantel, as typed records: every value below is followed by the verbatim passage it was taken from. Species as stated by each summary: Dogs and puppies.
Products
- Virbantel® Worm X Plus® (NADA/ANADA 141-261)
Virbantel® Worm X Plus® NADA 141-261, Original approval, March 13, 2007; sponsor Virbac AH, Inc.; species: Dogs and puppies; foi_id 815; FDA PDF
Indication
Treatment and control of roundworms (Toxocara canis, Toxascaris leonina), hookworms (Ancylostoma caninum, A. braziliense, Uncinaria stenocephala) and tapeworms (Dipylidium caninum, Taenia pisiformis) in dogs and puppies.
Dose regimen
Minimum 5 mg pyrantel pamoate and 5 mg praziquantel per kg body weight (2.27 mg of each per lb), Oral (flavored chewable; 30 mg/30 mg and 114 mg/114 mg sizes), Single administration by weight table, Dogs 6 lb and over; maximum potential exposure 11 mg/kg of each active per label tables
A minimum dose of 5 mg pyrantel pamoate and 5 mg praziquantel per kg body weight, (2.27 mg pyrantel pamoate and 2.27 mg praziquantel per lb body weight), according to the following dosing tables.
Target-animal safety
dose multiples 1X, 3X, 5X; duration 19 days; dosing once daily on Days 1-3 and Days 8-10 (two 3-day periods separated by 4 days); animals Thirty-two (four male and four female per group).
Test Animals: Thirty-two 12- week-old healthy Beagles, weighing between 2.65 and 4.64 kg at the beginning of the study. Four male and four female puppies were randomly assigned to each treatment group.
| Finding | Quote |
|---|---|
| Dosing regimen: 0, 11 (1X), 33 (3X) and 55 (5X) mg/kg of each of pyrantel pamoate and praziquantel once daily for two 3-day periods | 0, 11 (1X), 33 (3X), a nd 55 (5X) mg/kg of pyrantel pamoate and praziquantel each once daily for three consecutive days (Days 1, 2, 3) with a four-day non-treatment interval followed by a second three- day treatment period (Days 8, 9, 10). |
| Vomiting most frequent, dose-related | Vomiting was the most frequent clinical observation in dogs following treatment. The incidence of vomiting increased with dose. |
| Vomiting incidence, 5X group (n=8) on Days 1, 2, 3, 8, 9, 10: 8, 7, 3, 7, 8, 7 dogs (Table 1 row) | 5X 55 mg/kg 8 7 3 7 8 7 |
| Decreased activity in 7 dogs (1 placebo, 2 each in 1X, 3X, 5X); tremors in one 3X and one 5X dog; all mild and transient | Decreased activity was observed in 7 animals: 1 in the placebo group, 2 in the 1X group, 2 in the 3X group, and 2 in the 5X group. |
| ALT dose-by-time effect significant (5X Day 11, 3X Day 16) but within expected ranges | The dose by time effect was statistically significant for alanine aminotransferase (ALT) (p=0.0163). Two pertinent differences involving this interaction were significant: The 5X dose on Day 11 and the 3X dose on Day 16 had significantly higher means than the control group on their respective days. While elevated, these values remained within expected ranges. |
| No treatment-related necropsy or histopathology findings | There were no treatment-related findings either at necropsy or upon histopathological examination. |
Effectiveness
Dose-limiting Ascarid Study 2 (J.W. McCall, TRS Labs, Athens, GA): controlled laboratory study in 36 parasite-naive Beagles (9 weeks old) inoculated with 300 embryonated T. canis eggs, randomized to placebo, praziquantel 5 mg/kg, pyrantel pamoate 5 mg/kg or the combination (5 mg/kg each); necropsy worm counts on Day 7; percent effectiveness from geometric means. Additional dose-confirmation studies (D. caninum x3, T. pisiformis x2, T. canis study 1) all showed 98.6-100% effectiveness.; n = 9 per group, 4 groups; primary endpoint: Percent reduction in geometric mean T. canis worm counts vs controls (non-interference of praziquantel with pyrantel pamoate); result: Combination vs placebo 93% effective; combination vs praziquantel-alone 94%; pyrantel alone vs placebo 86%; combination vs pyrantel alone not significantly different (non-interference demonstrated).
Group 1: 9 dogs with T. canis GM=18.43, (range: 8-59) Group 2: 9 dogs with T. canis GM=19.61, (range: 3-65) Group 3: 6 dogs with T. canis GM=2.57, (range: 0-11) Group 4: 5 dogs with T. canis GM=1.22, (range: 0-8) Group 4 vs. Group 1* - Effectiveness: 93% Group 3 vs. Group 1 *- Effectiveness: 86% Group 4 vs. Group 2 *- Effectiveness: 94%
Adverse reactions
| Term | Treated | Control | Quote |
|---|---|---|---|
| Clinically normal approximately 1 h and 24 h post-dose (field palatability/safety study) | 110/123 | Out of the 123 dogs for which post-dose observations were recorded by the owner, 110 were clinically normal approximately 1 hour and 24 hours after treatment. The owners of six dogs reported abnormal observations 1 hour after dosing: vomiting (1 dog), vomiting and lethargy (1 dog), lethargy (3 dogs), and increased thirst (1 dog). | |
| Lethargy (1 h post-dose) | 3/123 | Out of the 123 dogs for which post-dose observations were recorded by the owner, 110 were clinically normal approximately 1 hour and 24 hours after treatment. The owners of six dogs reported abnormal observations 1 hour after dosing: vomiting (1 dog), vomiting and lethargy (1 dog), lethargy (3 dogs), and increased thirst (1 dog). | |
| Vomiting (1 h post-dose) | 1/123 (plus 1 dog with vomiting and lethargy) | Out of the 123 dogs for which post-dose observations were recorded by the owner, 110 were clinically normal approximately 1 hour and 24 hours after treatment. The owners of six dogs reported abnormal observations 1 hour after dosing: vomiting (1 dog), vomiting and lethargy (1 dog), lethargy (3 dogs), and increased thirst (1 dog). | |
| Vomiting (24 h post-dose) | 2 dogs | The owners of eight dogs reported abnormal observations 24 hours after dosing: vomiting (2 dogs), diarrhea (2 dogs), vomiting and bloody diarrhea (1 dog), lethargy continuing from the 1 hour post-dose observation (1 dog), coughing (1 dog), dry mouth and increased thirst (1 dog). | |
| Diarrhea (24 h post-dose) | 2 dogs | The owners of eight dogs reported abnormal observations 24 hours after dosing: vomiting (2 dogs), diarrhea (2 dogs), vomiting and bloody diarrhea (1 dog), lethargy continuing from the 1 hour post-dose observation (1 dog), coughing (1 dog), dry mouth and increased thirst (1 dog). | |
| Vomiting and bloody diarrhea (24 h post-dose; treated, recovered) | 1 dog | The owners of eight dogs reported abnormal observations 24 hours after dosing: vomiting (2 dogs), diarrhea (2 dogs), vomiting and bloody diarrhea (1 dog), lethargy continuing from the 1 hour post-dose observation (1 dog), coughing (1 dog), dry mouth and increased thirst (1 dog). |
Extraction notes: Original approval of the combination. The target animal safety section was not split by the parser (it sits inside the effectiveness text). Adverse reactions come from the uncontrolled field palatability/safety study in 126 client-owned dogs (post-dose observations recorded for 123). Laboratory palatability was 47.8% (failed), field palatability 72.0%. No PK data. The TAS 5X vomiting row and the design/dosage sentences are quoted as flattened text from the PDF ('a nd', 'three- day', '12- week-old' are extraction artifacts).
Reproduce: foi_structured_search(query="Pyrantel pamoate / Praziquantel") and foi_summary_get(foi_id=...) in dog-geroscience-mcp; dataset foi-summaries-dog (config structured).