THE IMPACT OF FORTETROPIN® ON SAFETY AND TOLERABILITY IN RETIRED HORSES
Myogenic atrophy in horses results from several conditions in the horse, such as Cushing’s disease to disuse atrophy secondary to injury, to malnutrition and secondary, to various genetic or immune-mediated myopathies. Fortetropin® (MYOS CORP, Cedar Knolls, NJ) is a proprietary all-natural product derived from fertilized egg yolk. Studies in people, dogs and cats demonstrated that Fortetropin® (300mg/kg dogs) increases rate of muscle protein synthesis, reduces muscle atrophy, increases lean muscle mass and decreased Liverpool Osteoarthritis in Dogs (LOAD) scores in geriatric dogs.
The efficacy of Fortetropin® in horses has not yet been studied. A 2022 study investigated the safety and tolerability of Fortetropin® at two doses (24g, 48g).
Fifteen client-owned horses, housed at a veterinary rehabilitation center, were randomly assigned to three treatment groups (n=5), and were fed 2-weeks of either a placebo (cheese powder), Fortetropin® (24g) or Fortetropin® (48g). The initial formulation containing only Fortetropin® was unpalatable. Sugar (4.5g-9g/serving) was added to the Fortetropin® and the study resumed. Serum chemistry, hematology, and fibrinogen, as well as physical exams and body weight were measured prior to the study; on the first day of administration and at the conclusion of the study.
Horses ranged in age from 9 to 27 years in age, included two mares and thirteen geldings, and had the following breeds represented: Arabian, Paint, Quarter Horse, Thoroughbred, and Warmblood.
No adverse events were observed in any of the horses in all three groups receiving placebo or the sweetened formulation of Fortetropin®. Horses readily ate this formulation top dressed on moistened stable mix pellets.
Body weight was maintained, with one horse in the placebo group losing 4.1% body weight, and three horses in the 48g Fortetropin® group gaining 10.6%, 3.2%, and 2.5% body weight, with the remaining horses staying static (1% change in BW). Physical exams were unchanged throughout the study, with normal TPRs. No clinically significant changes were observed in serum chemistry, hematology, and fibrinogen pre & post administration of Fortetropin® (see Annexes 1,2,3).
Our data suggest that horses tolerate Fortetropin® at doses of 72-109mg/kg. Further studies are needed on the efficacy of Fortetropin® in terms of the treatment of muscle atrophy in horses.
Investigator/Author:
Daizie Labelle, DVM, MBA, CCRP
drdaizie@petalumaequine.com
650-619-0338
Annexes
Annexe 1: Serum Chemistry - Out of Range
|
Horse |
Group |
Pre-Fortetropin®: Day 7 |
Post Fortetropin®: Day 21 |
|
1 |
48g |
K+(5.4); CA(14.3) |
|
|
2 |
48g |
CA(14.5); ALB(3.7) |
CA(14.7):BUN(26) |
|
3 |
48g |
|
GGT(32) |
|
4 |
48g |
K+ (5.4); Ca(14.2) |
K+(5.3); CA(14.2) |
|
5 |
24g |
K+(5.5); Glu (115) |
CA(14.6) |
|
6 |
24g |
|
K+(6.1) |
|
7 |
placebo |
GGT(41) |
|
|
8 |
placebo |
CA(14.3) |
K+(5.7) |
|
9 |
placebo |
ALB(3.7) |
ALB(3.7);GLOB(2.6) |
|
10 |
placebo |
K+(5.5); Ca (14.5) |
CA (15.1) |
|
11 |
24g |
K+ (5.5); CA(15.9), AST(132) |
K+(5.4);CA(15.1): AST(131) |
|
12 |
24g |
K+ (5.4) |
CA(14.3) |
|
13 |
48g |
|
K+(5.5) |
|
14 |
24g |
|
K+(5.9) |
|
15 |
placebo |
K+ (5.4) |
K+(5.3) |
Relevant reference ranges:
ALB: 2.2-3.7 g/dL, AST: 175-340 U/L, BUN: 7-25 mg/dL, CA: 11.5-14.2 mmol/L
K+: 5.5-5.2 mmol/L, GGT: 5-24 U/L, GLOB: 2.7-5.0 g/gL
Annexe 2: Hematology - Out of Range
|
Horse |
Group |
Pre-Fortetropin®: Day 7 |
Post Fortetropin®: Day 21 |
|
1 |
48g |
|
WBC(5.02) |
|
3 |
48g |
|
WBC(4.93) |
|
6 |
24g |
RBC(6.57) |
|
|
8 |
placebo |
|
WBC(4.94) |
|
10 |
placebo |
LYM(5.22) |
WBC(4.69) |
|
13 |
48g |
EOS(1.01) |
LYM(1.46) |
|
15 |
placebo |
WBC(4.81); LYM(1.37); HGB(10.9) |
LYM(1.49) |
*Platelets were verified manually - all were WNL
Relevant reference ranges:
WBC: 5.40-13.40 RBC: 6.80-12.90
LYM: 1.50-7.70 HGB: 11.0-19.0
EOS: 0.00-1.00
Annexe 3: Fibrinogen – Out of Range
|
Horse |
Group |
Pre-Fortetropin®: Day 7 |
Post Fortetropin®: Day 21 |
|
15 |
placebo |
101 |
258 |
Reference: 76-230 mg/dL
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