I recently heard about Nitroglycerine patches being used on people to treat tendon tears as it increases blood flow to the otherwise blood poor area and encourages healing. They are not without risks or sideeffects, but still seemed interesting. Anyone heard of this being used with horses?
(Note, this is purely an acedemic question, I do not have a horse with a tendon issue at the moment, knock wood)
I'm not sure that the effect as a local treatment is all that significant. It is more or less a systemic drug in patch form. And the body VERY quickly becomes tolerant of nitro, requiring frequent interruptions. All in all my guess would be that the application of heat would get more of an increase in flow than NTG.
But it's nice to hear of novel ideas being put out there! Ideally backed with research . . .
Hasn't the vasoconstriction hypothesis of laminitis been sort of supplanted by other proposed mechnisms? For a while I tried to keep up as vasodilators are sort of my thing, but I've lost the thread of what is "current" in laminitis theory.
There is virtually no risk to the heart itself using nitroglycerin outside of rare congenital things (which I don't even know if horses have) or really really bad valve problems. The heart LOVES nitro. It can cause headaches and temporarily drop the BP, but no digestive issues that I'm aware of.
I must say that is an exceptionally foolish drug to experiment with, especially for a young person. Drops in BP can be profound and fainting is not unheard of. The very young and the very old tolerate NTG pretty poorly sometimes.
I have used nitroglycerin ointment on children with digital ischemia due to high doses of IV vasopressor agents with some success. The problem is that usually the amount needed to dilate that particular area also causes significant hypotension. Without being able to communicate with the horse (i.e. he's not going to tell you he feels dizzy or headache-y) - I doubt I would try it. Also - tolerance occurs with continued use over time, so it's only going to be a useful therapy for short period of time, not for the months you would likely need for tendon healing. So...overall just not a good idea.
I recall using it to find veins back in the dark ages, too. As RB says, though, using it topically for a "local" effect is going to get you maybe a few hours before it stops being useful and starts being systemic.