I've tried to get the ones Doug mentions but found most suppliers only deal with companies, specifically health and safety depts. As he mentions, most decent commercial first aid its include some, but I haven't found a supplier who sells the tablets separately to the public<br><br>As an alternative you could try the capsules that ultra runners use - the two most popular being SUCCEED and E-Caps. <br><br>These masochists whom run 50 - 100 mile races swear by these which come in gel, drink or capsule (my favourite, as you can add to water).<br><br>These are electrolyte replacement capsules that have sodium and potassium and are readily available from several online stores for ultra runners<br><br>