Diuretics Flashcards
Hydrochlorothiazide
Hydrochlorothiazide
class: Thiazide Diuretic
MOA:
Blocks the sodium-chloride transporter in the thick ascending loop of Henle (TaLH) and the distal convuluted tubule (DCT). Leads to increased secretion of Na+, H2O, chloride, and also potassium via subsequent activation of RAAS.
Lowers BP FIRST by diuresis and after several weeks by peripheral vasodilation.
Uses:
first line anti-hypertensive drug for essential HTN
Can be used in CHF also
Usually perscribed with a beta-blocker.
Pk:
Onset: 2 hours
Peak effect: 2-6 hours
DOA: 6-24 hours
e1/2t: 8-12 hours
PB: 70% high
vD: 4-8 L/kg
excreted 100% unchanged in urine!!!!!
Dose:
25-100 mg PO/ day
max dose: 200 mg PO /day
has a ceiling effect so increasea dose has little increased effect.
SE:
- Hyponatremia
- Hypochloremia
- Hypokalemia
- Hyperglycemia
- Hyperuricemia
- Hypercholesteremia
- HYPOTENSION
- INCREASED R/F digoxin and lithium toxicity
- Can potentiate the effects of NMB
- Synergistic with ACE-I and BB
- NSAIDs decrease the effectivness of HCTZ
C/I:
- renal failure
- anuria
- decrease dose in elderly
- PREGNANCY
- AVOID ANTI-ARRTHYMIC AGENTS THAT PROLONG QT
Furosemide
Furosemide
Class: Loop diuretic
MOA: Inhibits the action of the Na-K-Chloride cotransporter in the thick ascending loop of Henle, leads to increased excretion of sodium, potassium, chloride and water.
Leads to PERIPHERAL VASODILATION and diuresis.
Uses:
diuresis, decrease preload volume, mobilization of edema in CHF patients.
Used to tx HYPERCALCEMIA by blocking the rebasoprtion of calcium.
Pk
onset: 1-2 minutes
Peak: within 30 minutes
DOA: 2-6 hours
E1/2T: 1-2 hours
PB: 90% - high
Excreted 60% unchanged in the kidneys, also in bile.
Dose:
- 1 to 1 mg/kg IV and titrate to effect.
- 1 to 0.4 mg/kg gtt
SE:
- hypotension
- hypokalemia
- hypernatremia
- hypochloremia
- hypomagnesemia
- dizziness/HA
- orthostatic hypotension
- arrthymias
- Potentiates ND-NMB
Caution:
- electrolyte disturbances
- renal failulre/anuria
- can increase the r/f digoxin and lithium toxicity
- increase possiblity of nephrotoxicity when perscribed with aminoglycosides and cephalosporins
- increase r/f otoxocitiy with aminoglycosides
Mannitol
Mannitol
class: 6 carbon sugar (hexose) osmotic diuretic
MOA:
Given IV, increases plasma osmolarity, draws fluid from ICF into ECF, then passes into the renal tubule, increases the osmolarity there and draws fluid into the tubule.
Uses:
- to decrease ICP, IOP
- Prophylaxis in acute kidney injury to flush fluid through kidneys.
- Also scavenges free radicals
Onset: 15 MINUTES
peak: within 30 minutes
DOA: 2 hours
E1/2T: 60-90 minutes
Not metabolized at all, excreted 100% unchanged in urine.
Dose
0.25 to 1 g/kg IV over 30-60 minutes
SE:
Hypovolemia/dehydration
Hypernatremia
Hyperchloremic alkalosis
hypokalemia
increase plasma osmolarity
Pulm edema
heach ache / vision changes
N/V rash
C/I:
Pulm edema
CV compromise
Caution in CHF
severe kidney failure
C/I in intracranial bleeding
