L4 | Urine Alkalinazation

Question 1

What are some drugs that increase the urine pH?

Answer 1

1. Sodium bicarbonate (IV)
2. Carbonic anhydrase inhibitors (diuretics)
3. Potassium Citrate

Some antacids like MgOH with AlOH can also somewhat increase the urine alkalinity

Question 2

What are the indications for urine alkalinization?

Answer 2

1. To increase the excretion of acidic drugs that are causing toxicity, e.g. salicylic acid, phenobarbitone. Weak acids break down into ions and can’t be reabsorbed in alkaline environments.
2. To increase the efficacy of certain drugs like (SACE) sulfanamides, aminoglycosides, cephalosporins and erythromycin.
3. To relieve dysuria
4. To prevent the formation of urate stones since urate dissolves in high pH.
5. To prevent the growth of certain organisms like E.coli
6. Prevent precipitation of sulfanamides.

Question 3

What are their adverse effects?

Answer 3

1. Calcium-phosphate stones: calcium isn’t dissolved in high pH which could increase the chances of calcium-phosphate stone formation
2. Increased pH decreases NH4 excretion which could lead to hyperammonemia and hepatic encephalopathy in patients with cirrhosis.