AS A PHARMACIST, you'll see cases where you can optimize oral loop diuretics (furosemide, etc) for volume overload or edema in heart failure. First, ensure that patients are on target doses of medications that improve heart failure outcomes. ACEIs or ARBs, beta-blockers, etc. Keep in mind, loops only treat symptoms. And evaluate other possible causes of fluid retention such as NSAID use, a high-salt diet, or nonadherence. Then suggest a stepwise approach to manage loops, but be aware, it can be more art than science. Expect doses to fluctuate.
Stick with furosemide. There's no good evidence other loops work better, despite better absorption. Plus furosemide not expensive than torsemide and bumetanide. Recommend starting with 20 to 40 mg in the morning and titrating every couple of days to the lowest dose that improves symptoms. Advise increasing the dose BEFORE adding a second dose, since loops need to reach a "threshold" concentration to cause diuresis. Think of the mantra, "double the dose until the urine flows". For example, suggest titrating to 80 mg in the morning. If that's not enough, advise adding 80 mg in the afternoon. Don't be surprised if patients with renal impairment need higher doses.
It's okay to try switching loops if symptoms persist on max daily doses of furosemide usually 240 mg, or up to 600 mg in kidney disease. Be familiar with equivalent doses. Explain oral furosemide 80 mg is roughly equal to torsemide 40 mg or bumetanide 2 mg.
Advise starting an aldosterone antagonist (spironolactone, etc) if patients aren't already on one especially for heart failure with reduced ejection fraction if eGFR is above 30 mL/min. Then suggest adding a thiazide if symptoms persist. Any thiazide is okay, but go with metolazone if eGFR is below 30 mL/min. Dispel the myth of dosing the thiazide 30 min before the loop. There's no evidence this works better than dosing at the same time. Emphasize close monitoring of electrolytes and renal function. Educate patients to check their weight daily and to report worsening edema or shortness of breath. For further information, see topic on Loop diuretic use in heart failure.
REFERENCES
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Mullens, W., Damman and others (2019). The use of diuretics in heart failure with congestion - a position statement from the Heart Failure Association of the European Society of Cardiology. European Journal of Heart Failure, 21(2), pp.137–155. Available at: https://pubmed.ncbi.nlm.nih.gov/30600580
Yancy, C.W., Jessup, M., Bozkurt, B., Butler, and others (2013). 2013 ACCF/AHA Guideline for the Management of Heart Failure. Circulation, 128(16). Available at: https://pubmed.ncbi.nlm.nih.gov/23741058