Diuretics Flashcards
IV to PO conversion of Furosemide?
Intravenous furosemide is twice as potent as oral furosemide
PO Furosemide conversion to Torsemide and Bumetanide?
In patients with normal renal function, the oral dose equivalence of furosemide relative to other oral diuretics is as follows
40 mg of furosemide = 20 mg of torsemide = 1 mg of bumetanide
What is the half life and duration of action of Furosemide?
The terminal half-life of furosemide is approximately 2 hours, and the total time of therapeutic effect is 6 to 8 hours. However, the half-life of furosemide will prolong in patients with chronic renal disease.
Use at minimum q 12 h dosing for Lasix (Dr. Yee)
How is Furosemide and all loop agents transported in the blood?
Furosemide glucuronide is a major biotransformation active product of furosemide having an active diuretic effect. In healthy individuals, greater than 95% of furosemide is bound to plasma protein, mainly albumin. Only 2.3% to 4.1% of furosemide is existent in an unbound form in therapeutic concentrations.
In situations with increases Creatinine how does the dosing of Lasix change?
Its a Threshold drug Use increased ↑↑ doses w/ decreased GFR
Lasix in our Right heart failure patients?
Furosemide less bioavailable in edematous states (gut swelling) which is typical of RHF patients
If patients have a sulfa allergy can you use a loop diuretic?
Yes and No. Lasix, Bumex, and torsemide are all sulfonamide type medications but Ethacrynic acid is a non sulfonamide
Not contraindicated with “sulfa” allergy
Hard-to-find
What is a efficacy marker of loop diuretics?
Seeing a lower Cl concentration- Dr. Yee
What is Benzothiadiazine?
The OG thiazide medication Secreted into Proximal tubule, act at DCT Relatively more Na/K-wasting Less potent than loop drugs Impairs dilution (hyponatremia)
What are the true Thiazides and the Thiazide like medications?
True thiazides (eg, HCTZ) HCTZ Chlorothiazide (iv) Indapamide Polythiazide Bendroflumethiazide Methyclothiazide
Thiazide-like
Metolazone
Chlorthalidone
What is the Equivalent dosing theory versus Double down for Lasix in AeHF?
Dose trial (2011) basically if a patient is on home 40 mg PO lasix and come in for AeHF you can give 20 mg IV lasix (equivalent theory) with the logic that Lasix is a non-dose dependent medication the response you get is not related to the concentration of drug just reaching minimum threshold and the patient is on 40 at home so you know they respond to this.
Counterpoint is to use 40-60mg IV Lasix or double down. This is because you make assumption that patient that patients current dose is not giving any diuresis.
There is no MAJOR difference but some subtle nuances. 1). if a patient is sick AF use double down. 2). If a patient has a clinical history that they have never improved on lasix or have never peed more on this dose double down. 3). If patient was just non-compliant or ate salt but their normal diuretic worked use Equivalent theory.
Pulmonary HTN patients are special: these patients develop high amounts of gut edema with their right heart failure and cannot absorb their normal PO medicines, strongly consider equivalent theory in these people.
