Hi Journeyman,
Your Red Triangles contain 120mg of Sildenafil Citrate that's the active ingredient in Viagra and many other ED medications. Viagra is available up to 100mg dose. I personally dont need to take a dose anywhere near 100mg, but if you need more than 100mg take more than one pill of Sildenafil Citrate. Although my vet recommended I never took more than 100mg.
As Mr Fishy suggests buy your Sildenafil from a reputable UK pharmacy like Dr Fox and if you really need more than one you can do so.
As I am sure you are aware the fact the tabs where triangular or red make no difference to Sildenfils efficacy