Drugs to Treat Hypo/hypernatremia (Wolff)

Question 1

Isotonic (0.9%) NaCl (normal saline) has what effect on volumes?

0.45% NaCl has what effect?

3% or 5% NaCl?

5% albumin?

5% dextrose (D5W)?

Answer 1

1) Increases ECF volume
2) Expands both ICF and ECF
3) Expands ECF while shrinking ICF
4) Expands plasma volume
5) Expands total body water

Question 2

If the GFR falls due to ACE inhibition than what happens in all patients?

What effect does it have in diabetic patients?

Answer 2

1) Increases serum creatinine

2) Preserves kidney function

Question 3

What effect does renal sympathetic nerve activity have on NaCl excretion?

Renin-Angiotensin-Aldosterone activity?

Atrial Natriuretic Peptide activity?

Answer 3

1) Decreases
2) Decreases
3) Increases

Question 4

Hypernatremia is defined as plasma sodium concentration greater than?

Hyponatremia less than?

What is the normal value of plasma osmolality?

Answer 4

1) 145 mEq/L
2) 135 mEq/L
3) 285 – 295 mOsm/kg

Question 5

What is the most common electrolyte abnormality encountered in clinical practice?

Answer 5

Hyponatremia

Question 6

What should be done to treat hyponatremia if a patient presents with severe symptoms such as vomiting, seizure, obtundation, respiratory distress and coma?

Answer 6

Hypertonic NaCl first followed by fluid restriction or vaptan

Question 7

What should be done to treat hyponatremia if a patient presents with moderate symptoms such as nausea, confusion, disorientation, and altered mental status?

Answer 7

Vaptan or hypertonic NaCl first followed by fluid restriction

Question 8

What should be done to treat hyponatremia if a patient presents with no or minimal symptoms such as headache, irritability, inability to concentrate, altered mood, falls or unstable gait?

Answer 8

Fluid restriction

Question 9

Overly rapid correction of hyponatremia can cause?

Answer 9

Osmotic demyelination syndrome

Question 10

What is the overall MOA of vaptans?

Answer 10

Block the antidiuretic hormone receptor in the collecting duct

Question 11

Which vaptan is a non-peptide arginine vasopressin receptor antagonist (AVP=ADH), with affinity for AVP receptor subtypes V1A and V2?

Which is a selective V2 receptor antagonist?

Answer 11

1) conivaptan

2) tolvaptan

Question 12

How is conivaptan administered?

How is tolvaptan?

Answer 12

1) IV

2) Orally

Question 13

What effect do the vaptans have?

What is its clinical application?

Answer 13

1) Increases free water clearance

2) Treatment of euvolemic and hypervolemic hyponatremia

Question 14

Tolvaptan is used to slow progression of?

Why must you use tolvaptan less than 30 days for hyponatremia treatment?

Answer 14

1) Adult polycystic kidney disease

2) Hepatotoxicity

Question 15

What effect do vaptans have on plasma volume and plasma osmolality primarily due to an increase in plasma sodium concentration?

Answer 15

1) Decreases plasma volume

2) Increases plasma osmolality

Question 16

What are vaptans metabolized by which can cause drug interactions?

Answer 16

CYP3A4

Question 17

What do you use to treat hypernatremia if the patient is also hypovolemic?

In other patients you use?

Answer 17

1) Isotonic saline

2) Hypotonic IV solutions

Question 18

Overly rapid correction of hypernatremia can cause?

Answer 18

Brain edema

Question 19

What is a synthetic analogue of the antidiuretic hormone arginine vasopressin and is a V2 selective agonist?

Answer 19

Desmopressin (DDAVP)

Question 20

What effect does desmopressin have due to its V2 stimulation?

Answer 20

Increases cAMP in the collecting duct which increases water permeability

Question 21

What effect does desmopress have on urine volume and urine osmolality?

Answer 21

1) Decreases urine volume

2) Increases urine osmolality

Question 22

What are the clinical applications for desmopressin?

Answer 22

1) Central diabetes insipidus

2) Primary nocturnal enuresis

Question 23

What black box warning does desmopressin have?

Answer 23

Life threatening hyponatremia

Question 24

How do you treat diabetes insipidus if the patient lacks ADH (central or neurogenic DI)?

Answer 24

Desmopressin

Question 25

How do you treat diabetes insipidus if the patient lacks ADH response (Nephrogenic DI)?

However this is contraindicated in what scenario?

Answer 25

1) Thiazide diuretics

2) Patient is undergoing Li+ therapy

Question 26

What is the treatment for Li-Induced Diabetes Insipidus?

Answer 26

Amiloride