Hard to say without knowing horse's weight and pentosan concentration
Recommended dose is 3 mg/kg. Most concentrations I have come accross are 250 mg/ml, though I have found 125 mg/ml.
Average horse =500 kg so you want 1500 mg for that weight.
(6mlx250 mg/ml=1500mg or 12mlx125 mg/ml=1500 mg).
If your vet is using PentAussie or something similar and your horse is around 1500 lbs, 15 mls sounds about right, maybe even a little low.
1500 lbs is approximately 700 kg
(700 kg x 3mg/kg=2100 mg *recommended dose
15ml x 125 mg/ml= 1875 mg *dose using 15 mls of 125 mg/ml)
Research suggests that higher doses may be more effective.
"PPS may not be sufficiently potent to demonstrate a clinical effect at the current dose of 3 mg/kg, which may be the reason many practitioners are recommending a higher dose of 6 mg/kg. Caution always should be used and attention to timing and dosage is important."
Even if your vet is using 250 mg/ml and your horse is 1500 lbs that still puts the dose under 6mg/kg (about 5.5 ish mg/kg).
I wouldn't be too alarmed. And I don't think breaking the dose up into 5 ml shots will give you any benefit at all :no:
Ask your vet about your concerns :yes: