Viagra for horse arthritis?

[ycbm]

Who'dathoughtit?

Report in HHO News section that they have got a really great result from injecting viagra into arthritic joints in horses.

Now I want to know who even thought of trying it, and why!
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[meleeka]

Blimey that’s random!

 

[AmyMay]

It sort of makes sense given it’s original developmental uses.

 

[ycbm]

It sort of makes sense given it’s original developmental uses.

So is it the use for erectile disfunction that was the out of the box thinking? I don't know the history of sildenafil.
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[AmyMay]

So is it the use for erectile disfunction that was the out of the box thinking? I don't know the history of sildenafil.
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Hypertension and angina.

 

[ycbm]

I still don't get the reason for trying it in a joint for arthritis.

Anyone in the drug industry who can explain how these leaps in usage arise?

Did the big data they collect now suggest that men who take viagra often get less arthritis?

 

[DabDab]

Don't know any details really, but did hear this being talked about at some point on some radio thing I was listening to. Basically it is to do with the effect this and similar drugs have on the lymphatic system - so they've been shown to improve the functioning of the lymphatic system if targeted into deficient sections of it, and thus reduce the occurrence of swelling. From what I remember it was being considered as quite a step forwards for humans with RA, because instead of treating the inflammation that has already occurred, it improves the affected area sufficiently to stop/significantly limit the inflammation occurring in the first place. I think it is also less of an immunosuppresant than current RA medicine too.

 

[Cloball]

The use in ED was a happy accident

It works as a vasodilator but it's quite selective and I've been out of the loop for a while. A quick look suggest cyclic GMP has been found to be involved in the breakdown and proliferation of cartilage. Sildenafil works by preventing the breakdown of cyclic GMP?

 

[Widgeon]

@ycbm you are on fire this morning Portslade Sainsburys made me LOL.

I'm going to resist asking whether it's the Viagra.

Joking aside, this is a bizarre but interesting subject!

 

[Abacus]

Researchers at the University of Rochester have discovered a novel use for PDE5 (phosphodiesterase type 5) inhibitors, such as Viagra, Cialis, and Levitra, which have the potential to ameliorate arthritic flare, as demonstrated in murine models of RA.

Other studies have shown that Viagra can have anti-inflammatory effects and so can help with arthritis flares.

Given the length of action for the more usual purpose (4 hours I think), I wonder how long it would last for in treating arthritis. Maybe not long enough to justify injecting a joint.

 

[ycbm]

The test was run over months and it was really effective.

It's in the news section if you can get through the paywall.

 

[Fransurrey]

Given the length of action for the more usual purpose (4 hours I think), I wonder how long it would last for in treating arthritis. Maybe not long enough to justify injecting a joint.

Don't forget that for ED it's taken orally and therefore the bioavailability will be much lower, due to inferior absorption and also first pass metabolism. I was lucky a few years ago to attend a seminar by I think Peter Ellis. The story from a drug discovery point of view was really interesting!

 

[Abacus]

Don't forget that for ED it's taken orally and therefore the bioavailability will be much lower, due to inferior absorption and also first pass metabolism. I was lucky a few years ago to attend a seminar by I think Peter Ellis. The story from a drug discovery point of view was really interesting!

It’s utterly amazing. I used to work in ‘health’ marketing (mostly pharma) and did a lot of research into Cialis, which is similar (but lasts for the usual purpose for 36 hours… yikes).

 

[abbijay]

I thought Viagra was supposed to make you stiff not loose things up! (sorry I only joined this post for the smutty jokes)

 

[SilverLinings]

There is more info on the research into the effect of PDE5 inhibitors on rheumatoid arthritis in humans in this paper, it also explains the mechanism by which it works:

Effect of sildenafil citrate on interleukin-1β-induced nitric oxide synthesis and iNOS expression in SW982 cells

The purpose of this study was to identify the effect of sildenafil citrate on IL-1β-induced nitric oxide (NO) synthesis and iNOS expression in human synovial sarcoma SW982 cells. IL-1β stimulated the cells to generate NO in both dose- ...

www.ncbi.nlm.nih.gov

For anyone who may not be aware, rheumatoid arthritis (joint damage caused by the immune system) is different to the more common osteoathritis (mechanically caused damage) which is seen in horses; I have only had a quick look at the research and not sure how effective this is likely to be for OA. General antinflammatory drugs are used to treat both, but RA patients usually also need immunosuppressants and/or targeted biologics (which also suppress the immune system).

The drugs used to treat more severe cases of RA are quite unpleasant and carry a raft of risks themselves, so something safer that avoids their use would be amazing for patients and save the NHS a lot of money. Also, RA itself puts patients at risk of the development of a variety of other serious and sometimes fatal conditions such as heart failure, vascular dementia and rheumatoid neuropathy so controlling it would lesson the chance of serious secondary disease.

On a tangent: Interestingly whilst looking at this I came across a couple of papers that show a link between exposure to cats during a patient's prepubertal period is linked to the subsequent diagnosis of RA, and that the length of exposure is linked to level of risk:

Rheumatoid arthritis: are pets implicated in its etiology? - PubMed

Rheumatoid arthritis (RA) is thought to be triggered by an environmental agent or agents in immunogenetically predisposed persons. To investigate if animals or animal products might be the disease reservoir for a putative environmental trigger for RA that acts in childhood, a case-control study...

pubmed.ncbi.nlm.nih.gov

Genetic susceptibility and the link between cat exposure and rheumatoid arthritis - PubMed

Risk for RA associated with prior intimate exposure to cats is concentrated in subjects with the RA-susceptibility conferring genotypes DRB1 *0401 and *0404. The findings suggest an interaction between an environmen-tal agent associated with pet cats and certain RA susceptibility-conferring DR...

pubmed.ncbi.nlm.nih.gov

 

[Widgeon]

On a tangent: Interestingly whilst looking at this I came across a couple of papers that show a link between exposure to cats during a patient's prepubertal period is linked to the subsequent diagnosis of RA, and that the length of exposure is linked to level of risk

How bizarre!! I haven't read the papers (at work atm) but presumably the researchers controlled for confounders? If so....yep that's weird. Will have to read them later

 

[SilverLinings]

How bizarre!! I haven't read the papers (at work atm) but presumably the researchers controlled for confounders? If so....yep that's weird. Will have to read them later

I only skimmed the abstracts but will have a better look later as the possible cat link isn't something I'd come across before.

RA is a funny disease as there are a few things that seem to predispose patients to it (they are thought to be born with the ability to develop RA and then something triggers it out of latency), including family history, but when researchers think they've found a strong link they then discover that it certainly doesn't apply to all patients. I've spoken to a couple of consultants about it recently and they think it likely that eventually different variants of RA may be identified, and we will realise that all RA patients don't have exactly the same disease. This could explain why some react to treatment very differently to others, as well as why different trigger factors affected some patients and not others.

 

[Widgeon]

RA is a funny disease as there are a few things that seem to predispose patients to it (they are thought to be born with the ability to develop RA and then something triggers it out of latency), including family history, but when researchers think they've found a strong link they then discover that it certainly doesn't apply to all patients. I've spoken to a couple of consultants about it recently and they think it likely that eventually different variants of RA may be identified, and we will realise that all RA patients don't have exactly the same disease. This could explain why some react to treatment very differently to others, as well as why different trigger factors affected some patients and not others.

Thanks, that makes a lot of sense. And it would explain "the cat thing"! Autoimmune disease in general are quite bizarre -and I know from recent work I've done that the treatment pathway for many of them is basically just starting with the cheapest drug then working upwards....which isn't exactly what you might call targeted.