Drugs to Treat Hypo/hypernatremia (Wolff) Flashcards
1) Isotonic (0.9%) NaCl (normal saline) has what effect on volumes?
2) 0.45% NaCl has what effect?
3) 3% or 5% NaCl?
4) 5% albumin?
5) 5% dextrose (D5W)?
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
If the GFR falls due to ACE inhibition than what happens in all patients?
What effect does it have in diabetic patients?
1) Increases serum creatinine
2) Preserves kidney function
What effect does renal sympathetic nerve activity have on NaCl excretion?
Renin-Angiotensin-Aldosterone activity?
Atrial Natriuretic Peptide activity?
1) Decreases
2) Decreases
3) Increases
Hypernatremia is defined as plasma sodium concentration greater than?
Hyponatremia less than?
What is the normal value of plasma osmolality?
1) 145 mEq/L
2) 135 mEq/L
3) 285 – 295 mOsm/kg
What is the most common electrolyte abnormality encountered in clinical practice?
Hyponatremia
What should be done to treat hyponatremia if a patient presents with severe symptoms such as vomiting, seizure, obtundation, respiratory distress and coma?
Hypertonic NaCl first followed by fluid restriction or vaptan
What should be done to treat hyponatremia if a patient presents with moderate symptoms such as nausea, confusion, disorientation, and altered mental status?
Vaptan or hypertonic NaCl first followed by fluid restriction
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?
Fluid restriction
Overly rapid correction of hyponatremia can cause?
Osmotic demyelination syndrome
What is the overall MOA of vaptans?
Block the antidiuretic hormone receptor in the collecting duct
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?
1) conivaptan
2) tolvaptan
How is conivaptan administered?
How is tolvaptan?
1) IV
2) Orally
What effect do the vaptans have?
What is its clinical application?
1) Increases free water clearance
2) Treatment of euvolemic and hypervolemic hyponatremia
Tolvaptan is used to slow progression of?
Why must you use tolvaptan less than 30 days for hyponatremia treatment?
1) Adult polycystic kidney disease
2) Hepatotoxicity
What effect do vaptans have on plasma volume and plasma osmolality primarily due to an increase in plasma sodium concentration?
1) Decreases plasma volume
2) Increases plasma osmolality
What are vaptans metabolized by which can cause drug interactions?
CYP3A4
What do you use to treat hypernatremia if the patient is also hypovolemic?
In other patients you use?
1) Isotonic saline
2) Hypotonic IV solutions
Overly rapid correction of hypernatremia can cause?
Brain edema
What is a synthetic analogue of the antidiuretic hormone arginine vasopressin and is a V2 selective agonist?
Desmopressin (DDAVP)
What effect does desmopressin have due to its V2 stimulation?
Increases cAMP in the collecting duct which increases water permeability
What effect does desmopressin have on urine volume and urine osmolality?
1) Decreases urine volume
2) Increases urine osmolality
What are the clinical applications for desmopressin?
1) Central diabetes insipidus
2) Primary nocturnal enuresis
What black box warning does desmopressin have?
Life threatening hyponatremia
How do you treat diabetes insipidus if the patient lacks ADH (central or neurogenic DI)?
Desmopressin
How do you treat diabetes insipidus if the patient lacks ADH response (Nephrogenic DI)?
However this is contraindicated in what scenario?
1) Thiazide diuretics
2) Patient is undergoing Li+ therapy
What is the treatment for Li-Induced Diabetes Insipidus?
Amiloride
