Ryle, I know that we have a large hanoverian gelding that has to have a shot once a week...it just doesn't stay effective longer than that. It might work differently with other horses, but for this guy, you can really tell when he's "due" for his shot....
Effectiveness is going to vary depending on the amount of arthritic changes already present in the joint and the daily activity level of the horse. If he is needing an injection a week then it's likely that you need to look at more aggressive treatment to break the inflammatory cycle and then Adequan IM as a maintenance treatment.
They would do better to add in an anti-inflammatory between joint injections such as low dose bute every other day or every 3 days. Since the risk of gastric issues with bute is dose dependent using lower dosing and spreading the dosing out greatly reduces the risk. Plus allowing free-choice forage reduces risks of GI issues as well. And the effect of Bute lasts for more than 24 hours so dosing every 2-3 days can be quite effective. Another option would be to use Surpass which is a topical NSAID that can be applied to the area that is causing pain. It still has the risks associated with NSAID's like Bute, but you concentrate the effectiveness to the area that needs it.
Yes, surpass is a prescription NSAID just like bute and you aren't supposed to use the two together because it increases the risk of GI irritation/ulceration.
MSM does have some anti-inflammatory properties, but just like everything else it only does so much. Glucosamine at higher doses than normally given and in conjunction with MSM has shown the best result in the the few reliable studies done on supplements for joint issues in horses. I tend to double the label dose of glucosamine as most products recommend dosing quite a bit lower than what the study showed to be effective.
Sounds like this guy has some advances joint disease. Poor thing.
I'm new here but my old, very arthritic mare was on Adequan IM for the last 4 years. Four years she wouldn't have been alive without it. ( She was Euthanized two weeks ago because finally nothing could hold the pain at bay).
I'm not big on buying meds from anywhere other than vets...but here's a secret...Entirely Pets website will sell you Adequan without a prescription for about $48/dose.
I certainly wouldn't be afraid to try it for any old arthritic horse.