Drug-Induced Kidney Disease- Lithium

Question 1

Pathogenesis of Li-induced CKD: chronic interstitial nephritis

Answer 1

Basically the same thing as AIN, but chronic…duh lol

Question 2

Pathogenesis of Li-induced CKD: minimal change disease, FSGS

Answer 2

damage the kidney –> lose nephron mass –> CKD.

Treatment is to D/C Li and treat the CKD

Question 3

Pathogenesis of Li-induced CKD: nephrogenic diabetes insipidius

Answer 3

Prevents the kidney from responding to ADH –> you pee out a lot of water

Question 4

Risk factors for Li-induced CKD

Answer 4

duration of therapy
episodes of acute Li toxicity
CUMULATIVE Li EXPOSURE (exposure to a lot of Li and Li concentrations are high enough for a long time)

Question 5

Li-induced CKD prevention

Answer 5

routine TDM of Li concentrations (0.6-1.2 is goal)
avoiding dehydration
monitoring renal function over time
avoid DDIs (HCTZ)

Question 6

Treatment of Li-induced CKD: general approaches

Answer 6

D/C Li
HYDRATION
Avoid other nephrotoxic drugs
Monitor renal function

Question 7

Treatment of Li-induced CKD: nephrogenic diabetes insipidius

Answer 7

Amiloride 5-20mg QD, treats the polyuria and polydipsia

Question 8

Does amiloride treat the CKD?

Answer 8

NO! Only treats the symptoms of nephrogenic DM insipidius

Question 9

Amiloride MoA

Answer 9

Potassium-sparing diuretic that blocks the ENaC channel where Li enters and prevents Li from getting into the cell and causing DM insipidius

Question 10

What does Li do if it gets inside the cell and passes through the ENaC channel?

Answer 10

It blocks ADH and H2O reabsorption