Dose-response study of intravenous torsemide in congestive heart failure

The Potential Role of Torsemide in Optimizing Loop Diuretic Therapy for Heart Failure Patients

Heart failure is associated with an increased frequency of hospitalization, reduced life span, and greater risk to public health, thus posing a challenge. In India, torsemide is one of the commonly used loop diuretics for decongestion in heart failure. However, this use of torsemide, including its dosing, and up/down titration, is based on practical experience. Loop diuretic therapy for heart failure patients poses several dilemmas due to the lack of robust evidence based on which treatment decisions can be made. To guide physicians on the optimal use of torsemide in heart failure patients with or without renal impairment, a panel of expert cardiologists and nephrologists from India convened to develop this expert opinion document for the use of torsemide. This expert opinion on torsemide will pave the way for optimal management with loop diuretic therapy in real-world heart failure patients.

Torsemide Pharmacometrics in Healthy Adult Populations Including CYP2C9 Genetic Polymorphisms and Various Patient Groups through Physiologically Based Pharmacokinetic-Pharmacodynamic Modeling

Torsemide is a widely used diuretic in clinical practice. In this study, pharmacokinetic (PK) and pharmacodynamic (PD) simulations of torsemide for various population groups and exposure scenarios were performed through human-scale physiologically-based PK-PD (PBPK-PD) modeling of torsemide. For PBPK-PD modeling of torsemide, invitro and clinical data of torsemide reported previously were used. After exposure to clinical doses of torsemide, observed plasma (or serum) concentration and urine torsemide excretion profiles were used as PK-data, and observed urinary sodium excretion rate was used as PD-data. The model was then extended to take into account physiological and biochemical factors according to different CYP2C9 phenotypes or patient populations. The established model captured various torsemide clinical results well. Differences in torsemide PKs and PDs between patient groups or CYP2C9 genetic polymorphisms were modelologically identified. It was confirmed that degrees of differences in torsemide PKs and PDs by disease groups were greater than those according to different CYP2C9 phenotypes. According to torsemide administration frequency or dose change, it was confirmed that although the difference in plasma PKs between groups (healthy adult and patient groups) could increase to 14.80 times, the difference in PDs was reduced to 1.01 times. Results of this study suggested that it is very important to consider disease groups in the setting of torsemide clinical therapy and that it is difficult to predict PD proportionally with only differences in PKs of torsemide between population groups. The PBPK-PD model established in this study is expected to be utilized for various clinical cases involving torsemide application in the future, enabling optimal drug therapy.

Comparative effects of furosemide and other diuretics in the treatment of heart failure: a systematic review and combined meta-analysis of randomized controlled trials

Diuretics have an essential role in the management of heart failure (HF). However, each drug has its own benefit and side effect. Side effects include fluid, electrolyte abnormalities, and acid-base disturbance. These adverse effects of diuretics predispose patients to serious cardiac arrhythmias and may increase the risk of arrhythmic mortality. Herein, we aim to summarize the relative efficacy and safety of all available diuretics used in the treatment of patients with HF. In June 2017, a systematic electronic database search was conducted in nine databases. All randomized controlled trials (RCTs) comparing the different diuretics used in HF were included for meta-analysis. The protocol was registered in Prospero with CRD42018084819. Among the included 54 studies (10,740 patients), 34 RCTs were eligible for quantitative network meta-analysis (NMA) and traditional meta-analysis while the other 20 studies were qualitatively analyzed. Our results showed that azosemide and torasemide caused a significant reduction in brain natriuretic peptide (BNP) level. Torasemide also caused a significant decrease in collagen volume fraction (CVF) and edema. No significant difference between the agents concerning glomerular filtration rate (GFR), water extraction, and sodium excretion was demonstrated. Regarding side effects, no significant difference among diuretics was observed in terms of hospital readmission and mortality rates. Diuretics are the main treatment of hypervolemia in HF patients. The choice of appropriate diuretic is essential for successful management and is mainly guided by patient clinical situations and the presence of other co-morbidities.

Torasemide versus furosemide in treatment of heart failure: A systematic review and meta-analysis of randomized controlled trials

AIM

Diuretics are a cornerstone in treatment of heart failure (HF). Torasemide is a loop diuretic with a potential advantage over other diuretics. We aim to meta-analyse and compare the effect of torasemide with furosemide in HF patients.

METHODS

A comprehensive literature search using 12 databases including PubMed, Scopus, and Web of Science was performed. All randomized controlled trials (RCTs) comparing furosemide and torasemide in HF patients were included and meta-analysed. We assessed the risk of bias using Cochrane Collaboration's tool. The protocol was registered in PROSPERO (CRD42016046112).

RESULTS

Eighteen RCTs with 1598 patients were included. There was a significant difference between torasemide 20 mg and furosemide 40 mg in increasing the urine volume (standard difference of the mean (SDM) [95% confidence interval] = -0.78 [-1.52 to -0.053], P = .036). Torasemide 10 mg and 10 to 20 mg have a significant effect on potassium excretion in comparison with furosemide 25 to 40 mg (P = .018 and .023, respectively). In general, torasemide and furosemide have no significant difference in mortality, edema improvement, weight loss, heart rate, and reducing systolic/diastolic blood pressure. However, oral torasemide has a significant lower hospital stay P < .001 and superior effect in improving ejection fraction P = .029.

CONCLUSION

Although not all results are statistically significant, torasemide has potential advantages on multiple aspects of HF management when compared with furosemide. More studies are needed to clarify these effects.

Practical applications of intravenous diuretic therapy in decompensated heart failure

Intravenous (IV) loop diuretics play an important role in the treatment of decompensated heart failure (DHF). They inhibit the Na(+)-K(+)-2Cl(-) reabsorptive pump in the thick ascending limb of the loop of Henle, and the resultant natriuresis and diuresis decreases volume load, improves hemodynamics, and reduces DHF symptoms. However, loop diuretics have a short half-life and their efficacy may be limited by postdiuretic sodium rebound during the period between doses in which the tubular diuretic concentration is subtherapeutic. Moreover, they can produce electrolyte abnormalities, neurohormonal activation, intravascular volume depletion, and renal dysfunction. Several studies have reported an association between diuretic therapy and increased morbidity and mortality. In addition, many patients, especially those with more advanced forms of heart failure (HF), are resistant to standard doses of loop diuretics. These high-risk, resistant patients may benefit from pharmacologic and/or nonpharmacologic interventions to improve hemodynamic performance, treatment of renovascular disease, discontinuation of aspirin and other sodium-retaining drugs, manipulation of the route of delivery or combination of diuretic classes, or hemofiltration. Despite >50 years of use, many questions regarding the use of intravenous diuretic agents in patients with DHF are still unanswered, and there remains a compelling need for well-designed randomized, controlled clinical trials to establish appropriate treatment regimens that maximize therapeutic benefit while minimizing morbidity and mortality.

Ultrafiltration in decompensated heart failure

Fluid congestion is the hallmark of decompensated heart failure. As heart failure progresses, reduced response to diuretics is common. In these patients, ultrafiltration has been found to alleviate excess volume and improve diuretic sensitivity. Compared with diuretics, ultrafiltration provides a more predictable and safer way to achieve euvolemia with minimal electrolyte abnormalities and neurohormonal activation. The emerging familiarity and ease of use of ultrafiltration suggests that in the future this will be an important therapy for the treatment of acute and chronic volume overload associated with decompensated heart failure.

Pharmacodynamics of torsemide administered as an intravenous injection and as a continuous infusion to patients with congestive heart failure

The natriuretic and diuretic effects of a 100-mg dose of torsemide administered as a continuous infusion of torsemide and as a single bolus were compared in a group of patients with stable mild-to-moderate congestive heart failure (CHF). Patients received in random order 100 mg of torsemide as an intravenous bolus and as a 75-mg infusion over 24 hours started simultaneously with a 25-mg loading bolus. Administration of torsemide to patients with CHF as a continuous infusion was an effective dosing regimen, resulting in 24-hour diuresis and natriuresis that was numerically but not statistically greater than that observed with bolus administration. The response with continuous infusion occurred with less torsemide in the urine, resulting in a significantly greater efficiency of torsemide with this regimen. The effectiveness of torsemide as a continuous infusion does not mean that this mode of administration should be used in all patients. The response to 100 mg of torsemide in patients with mild-to-moderate CHF is the same whether administered as an intravenous bolus, a continuous intravenous infusion, or by mouth. This is consistent with the high bioavailability demonstrated in previous studies. The mode of therapy used should be dictated by each individual patient's needs. This study shows that continuous infusion is a viable option for administration of torsemide, and dosing guidelines for use of such a strategy are presented.

Torsemide: a pyridine-sulfonylurea loop diuretic

OBJECTIVE

To review the clinical pharmacology of torsemide and to compare it with currently available loop diuretics, particularly furosemide.

DATA SOURCES

An English-language MEDLINE search, 1985 to October 1994, was used to identify pertinent literature, including review articles.

DATA EXTRACTION

Data from scientific literature were extracted, evaluated, and summarized for presentation. Pivotal and representative studies are discussed relating to the pharmacology, pharmacokinetics, and use of torsemide in patients with congestive heart failure, renal disease, hepatic disease, and hypertension.

DATA SYNTHESIS

Torsemide is a loop diuretic of the pyridine-sulfonylurea class. The bioavailability of torsemide is approximately 80%, with little first-pass metabolism, and torsemide can be given without regard to meals. The serum concentration reaches its peak within 1 hour after oral administration and diuresis lasts approximately 6-8 hours. Torsemide is eliminated both hepatically (80%) and renally (20%) as unchanged drug with an elimination half-life of about 3.5 hours. Because of the high bioavailability, oral and intravenous doses are therapeutically equivalent. Torsemide, and other loop diuretics such as furosemide, are indicated for the treatment of edema associated with congestive heart failure, renal disease, and hepatic disease. They also are indicated for the treatment of hypertension alone or in combination with other antihypertensive agents. Depending on the indication, the recommended initial adult dosage of torsemide is between 5 and 20 mg once daily orally or intravenously. Special dosage adjustments in the elderly are not necessary.

CONCLUSIONS

Torsemide is a loop diuretic similar to furosemide, with similar indications. Torsemide is characterized by good bioavailability and once-daily dosing and, compared with furosemide, provides generally equivalent therapeutic efficacy.