Yes I’m from the UK and my GP orders a Potassium blood test and a Bicarbonate blood test (HCO3?) every couple of months because Diamox can reduce both of these. Also, can I add, when taking Bicarbonate of Soda you have to be careful that you don’t neutralise your stomach acid before eating (as this will lead to other problems) best time to take is when you’re not going to be eating, say at least an hour after eating.
Have you tried experimenting with your dose, for best results ? e.g. I find a half tablet of Diamox (=125mg), taken 3 times a day is sufficient in my case. As far as I know it’s a relatively short-lived drug once in your system, so you need to remember to take it regularly, to maintain it’s effectiveness.