Efficacy of Intravenous Chlorothiazide for Refractory Acute Decompensated Heart Failure Unresponsive to Adjunct Metolazone

A Systematic Review and Meta-Analysis of Metolazone Compared to Chlorothiazide for Treatment of Acute Decompensated Heart Failure

Treatment of volume overload in the setting of acute decompensated heart failure (ADHF) is typically achieved through the use of loop diuretics. While they are highly effective, some patients may develop loop diuretic resistance. One strategy to overcome this scenario includes sequential nephron blockade with a thiazide-type diuretic; however, it is unknown which thiazide-type diuretic used in this setting is most effective. A systematic review and meta-analysis were performed to compare the efficacy and safety of chlorothiazide with metolazone as add-on therapy in the setting of loop diuretic resistance for the treatment of ADHF. Literature searches were conducted through PubMed, Google Scholar, and Science Direct from inception through February 2020 using the following search terms alone or in combination: metolazone, chlorothiazide, acute decompensated heart failure, loop diuretic, and urine output. All English-language prospective and retrospective trials and abstracts comparing metolazone to chlorothiazide for the treatment of ADHF were evaluated. Studies were included if they analyzed urine output for at least 24 hours in patients with ADHF. Meta-analysis was conducted to evaluate pooled effect size by using a random-effect model. Primary outcomes included net and total urine output. Secondary outcomes included commonly reported safety outcomes. Four studies comparing the use of metolazone to chlorothiazide as an adjunct to loop diuretics to treat ADHF were included in the evaluation. Metolazone was as effective as chlorothiazide to augment loop diuretic therapy in ADHF in most studies with no pooled difference in net or total urine output. However, there were notable differences in baseline loop diuretic dosing, ejection fraction, renal function, race, and endpoint timing across studies. Adverse effects were commonly observed and included electrolyte abnormalities, change in renal function, and hypotension but were comparable between groups. Metolazone is as effective as chlorothiazide as add-on to loop diuretics in treating ADHF without an increase in safety concerns.

A narrative review of pharmacologic de-resuscitation in the critically ill

Despite evidence highlighting harms of fluid overload, minimal guidance exists on counteraction via utilization of diuretics in the de-resuscitation phase. While diuretics have been shown to decrease net volume and improve clinical outcomes in the critically ill, a lack of standardization surrounding selection of diuretic regimen or monitoring of de-resuscitation exists. Current monitoring parameters of de-resuscitation often rely on clinical signs of fluid overload, end organ recovery and other biochemical surrogate markers which are often deemed unreliable. The majority of evidence suggests that achieving a net-negative fluid balance within 72 h after shock resolution may be of benefit; however, approaches to such goal are uncertain. Loop diuretics are a widely available type of diuretic for removal of volume in patients with sufficient kidney function, with the potential for adjunct diuretics in special circumstances. At present, administration of diuretics within the broad critically ill population fails to find uniformity and often efficacy. Given the lack of randomized controlled trials in this susceptible population, we aim to provide a thorough therapeutic understanding of diuretic pharmacotherapy which is necessary in order to achieve desired goal of fluid balance and improve overall outcomes.

Diuretic Strategies for Loop Diuretic Resistance in Acute Heart Failure: The 3T Trial

OBJECTIVES

This study compared combination diuretic strategies in acute heart failure (AHF) complicated by diuretic resistance (DR).

BACKGROUND

Combination diuretic regimens to overcome loop DR are commonly used but with limited evidence.

METHODS

This study was a randomized, double-blinded trial in 60 patients hospitalized with AHF and intravenous (IV) loop DR. Patients were randomized to oral metolazone, IV chlorothiazide, or tolvaptan therapy. All patients received concomitant high-dose IV infusions of furosemide. The primary outcome was 48-h weight loss.

RESULTS

The cohort exhibited DR prior to enrollment, producing 1,188 ± 476 ml of urine in 12 h during high-dose loop diuretic therapy (IV furosemide: 612 ± 439 mg/day). All 3 interventions significantly improved diuretic efficacy (p < 0.001). Compared to metolazone (4.6 ± 2.7 kg), neither IV chlorothiazide (5.8 ± 2.7 kg; 1.2 kg [95% confidence interval (CI)]: -2.9 to 0.6; p = 0.292) nor tolvaptan (4.1 ± 3.3 kg; 0.5 kg [95% CI: -1.5 to 2.4; p = 0.456) resulted in more weight loss at 48 h. Median (interquartile range [IQR]) cumulative urine output increased significantly and did not differ among those receiving metolazone (7.78 [IQR: 6.59 to 10.10] l) and chlorothiazide (8.77 [IQR: 7.37 to 10.86] l; p = 0.245) or tolvaptan (9.70 [IQR: 6.36 to 13.81] l; p = 0.160). Serum sodium decreased less with tolvaptan than with metolazone (+4 ± 5 vs. -1 ± 3 mEq/l; p = 0.001), but 48-h spot urine sodium was lower with tolvaptan (58 ± 25 mmol/l) than with metolazone (104 ± 16 mmol/l; p = 0.002) and with chlorothiazide (117 ± 14 mmol/l; p < 0.001).

CONCLUSIONS

In this moderately sized DR trial, weight loss was excellent with the addition of metolazone, IV chlorothiazide, or tolvaptan to loop diuretics, without a detectable between-group difference. (Comparison of Oral or Intravenous Thiazides vs. tolvaptan in Diuretic Resistant Decompensated Heart Failure [3T]; NCT02606253).

Advances in chemical pharmacotherapy for managing acute decompensated heart failure

INTRODUCTION

Acute decompensated heart failure (ADHF) contributes largely to the burden of heart failure and is associated with a poorer prognosis. Although numerous clinical trials evaluated the benefit of newer medications for ADHF, most of them were not successful. Areas covered: This review focusses on the updates on recent developments in chemical pharmacotherapy for the management of ADHF. A MEDLINE search for relevant review articles and original investigations on newer drugs for ADHF provided us with necessary literature. Expert opinion: Currently, popular therapies like diuretics, vasodilators, and inotropes offer symptomatic relief but do not provide survival benefit. Although multiple medications targeting novel pathways in ADHF were studied extensively, they failed to show either symptomatic or mortality benefit in available randomized trials. Improving our understanding of the complex pathophysiology of ADHF along with designing studies which include patients who are more representative of the real-world heart failure population, standardizing methods for endpoint assessment, and evaluating the role on novel biomarkers of organ dysfunction is important to improve ADHF research. Enhancing preventive strategies like improving baseline therapy in chronic heart failure patients and developing strategies for early identification of ADHF are important as our quest for innovative ADHF pharmacotherapy continues.

Intravenous Chlorothiazide Versus Enteral Metolazone to Augment Loop Diuretic Therapy in the Intensive Care Unit

BACKGROUND

In cases of loop diuretic resistance in the intensive care unit (ICU), recommendations for a specific second-line thiazide agent are lacking.

OBJECTIVE

To compare the effects of intravenous chlorothiazide (CTZ) and enteral metolazone (MET) on urine output (UOP) when added to furosemide monotherapy therapy in critically ill adults.

METHODS

This was a retrospective cohort study conducted in the medical, surgical, and cardiothoracic ICUs of a quaternary medical center. The primary outcome was change in UOP induced by the study interventions compared with furosemide alone. Secondary outcomes included onset of diuresis, eventual need for hemodialysis, and incidence of adverse events.

RESULTS

A total of 122 patients (58 in CTZ, 64 in MET) were included. When added to furosemide monotherapy, CTZ induced a greater change in UOP at 24 hours compared with MET (2405 vs 1646 mL, respectively; P = 0.01). CTZ also caused a more rapid dieresis: 1463 mL total UOP in the first 6 hours compared with 796 mL in the MET group ( P < 0.01). There were no differences found regarding ICU length of stay, need for renal replacement therapy, or survival to discharge. The CTZ arm required more potassium supplementation to maintain normokalemia (median 100 vs 57 mEq in MET; P = 0.02) and carried a higher cost (mean $97 vs $8, P < 0.01).

CONCLUSION

Both CTZ and MET induced significant increases in UOP. CTZ induced a greater and more rapid change and was associated with higher cost and greater need for potassium replacement. Randomized controlled trials are needed to establish whether a preferable thiazide diuretic exists in this setting.