Pharmacology: Hypernatremia, Hyponatremia Flashcards
describe the effects of IV solutions:
isotonic (0.9%) NaCl
increases ECF volume
describe the effects of IV solutions:
0.45% NaCl
expands ECF > ICF, but both do expand
describe the effects of IV solutions:
3% or 5% NaCl
expand ECF, shrink ICF
describe the effects of IV solutions:
5% albumin
expand plasma volume
describe the effects of IV solutions:
5% dextrose (D5W)
expands total body water, equivalent to infusing distilled H2O
dextrose is rapidly metabolized to CO2 leaving behind H2O
describe the effects of renal sympathetic nerves
increase activity: decrease NaCl excretion
- decrease GFR (vasoconstriction of afferent art.)
- increase renin secretion
- increase proximal tubule, TAL, and CD NaCl reabsorption
describe the effects of renin-angiotensin-aldosterone
increase secretion: decrease NaCl excretion
- increased angiotensin II levels stimulate proximal tubule NaCl reabsorption
- increased aldosterone levels stimulate TAL and CD NaCl reabsorption
- increase ADH secretion
describe the effects of atrial natriuretic peptide
increase secretion: increase NaCl excretion
- increase GFR (vasoconstriction efferent art.)
- decrease renin secretion
- decrease aldosterone secretion
- decrease NaCl and H2O reabsorption by the CD
- decrease ADH secretion and inhibition of ADH action on the CD
describe the effects of ADH
increase secretion: decrease H2O excretion
- increase H2O absorption by the CD
hypovolemia independently stimulates…
ADH secretion
what is the most common carcinoma leading to ectopic production of vasopressin and SIADH?
oat-cell carcinoma
will need indefinite treatment, at high risk of chronic SIADH
describe level 1 treatment for patients with hyponatremia
fluid restriction
symptoms are minimal: HA, irritability, inability to concentrated, altered mood, depression, falls or unstable gait
describe level 2 treatment for patients with hyponatremia
vaptan or hypertonic NaCl, followed by fluid restriction
moderate symptoms: N, confusion, disorientation, altered mental status
describe level 3 treatment for patients with hyponatremia
hypertonic NaCl, followed by fluid restriction or vaptan
severe symptoms: V, seizures, obtundation, respiratory distress, coma
this drug class blocks the ADH receptor (AVPR2) in the CD
vaptans