Here again there are no Podiatrists in Mexico. Medical School of Podiatry is a separate degree from a medical doctor in the US.
There may be retired Podiatrists living here but the other individuals who treat feet locally are not what is known as a Podiatrist.
Yes it is available but I do not know the cost. Metoprolol is the generic name and when you are in Mexico just show the name and strength in writing (as you typed it). Do not try to pronounce it or ask for it verbally unless you are fluent in Spanish.
You should be getting the minerals you need from food and vitamins with minerals. Water is H2O. I would prefer my water be as pure as possible although I know some minerals, etc. are to be expected.