Bit o' quantitative trivia to back up why I yabber on about Calcium Carbonate when using:
When using stimulants the pH of nephrotic system becomes markedly acidic due to the inherent dehydration preventing dilution of metabolic products along with insufficient Na+ intake inhibiting adequate transport of valuable electrolytes through the tubule membranes. Dysfunction of such a form is termed Renal Tubular Acidosis, the reasoning I would imagine is fairly obvious, and occurs at a pH level of 5.5 and below.
A simple but unbelievably painful consequence of chronic renal acidosis is the formation of kidney stones - formed from Uric acid, Cysteine residues and Calcium Oxalate deposits precipitating out of solution and coagulating until their mass cannot pass through the ureter.
Homeostatic basification of blood and waste occurs through secretion or retention of bicarbonate ions and respective salts.
Ensuring the system retains a stable pH is the easiest way to avoid what is often described as the most acutely painful affliction possible.
The proximal tubule functions to reabsorb ions of biological value (Na+/K+/Mg2+/Ca2+ etc.) along with glucose, amino acids and phosphate molecules among other things, from the urine prior to its transference to the bladder. During RTA the proximal tubule cannot sufficiently absorb the presented load which presents massive problems downstream within the distal tubule. Active transport of dissolved bicarbonate across the membrane results in a relative reduction in H+ secretion which indirectly worsens the acidosis once the bicarbonate ions are excreted in the urine. The consumption of Na+ by transporter proteins has a knock-on effect which ultimately results in the excessive excretion of K+. The system begins working in a desperate and self-destructive loop which worsens as time progresses.
Given Na+/K+/Mg2+/Ca2+ are responsible for the capacity of organic membranes to function along with the very ability of muscle tissue to alternate states of contraction and relaxation it should come as no surprise that insufficient concentrations result in massive systemic problems - weakness progresses to twitches, then to spasms and seizures while consciousness becomes involuntary. Cell death becomes tissue death which results in organ death and ultimately complete cessation of biological functioning.
Aside from reducing the likelihood of kidney stone formation and dying on the floor while performing an impression of a salmon on hot coals. the basification of the nephrotic system has a beneficial impact on drug metabolism, of particular importance with Amphetamines and their ilk.
At a pH of 7.0 roughly 30% is excreted completely unmetabolised, at 5.5-6 that figure skyrockets to over 60% of the dose being completely wasted!
Conversely, if the urinary pH is kept between 7.5 and 8 the vast majority of the dose undergoes the deamination pathway resulting in just 7% being excreted unchanged.
A handful of Tums and a few bottles of Gatorade are a very small price to pay for not having calcified kidneys, double the effectiveness of your drugs and continuation of your not being dead.