Furosemide given by inhalation ameliorates acute exacerbation of asthma

Is Inhaled Furosemide a Potential Therapeutic for COVID-19?

The potentially lethal infection caused by the novel Severe Acute Respiratory Disease Coronavirus-2 (SARS-CoV-2) has evolved into a global crisis. Following the initial viral infection is the host inflammatory response that frequently results in excessive secretion of inflammatory cytokines (e.g., IL-6 and TNFα), developing into a self-targeting, toxic "cytokine storm" causing critical pulmonary tissue damage. The need for a therapeutic that is available immediately is growing daily but the de novo development of a vaccine may take years. Therefore, repurposing of approved drugs offers a promising approach to address this urgent need. Inhaled furosemide, a small molecule capable of inhibiting IL-6 and TNFα, may be an agent capable of treating the Coronavirus Disease 2019 cytokine storm in both resource-rich and developing countries. Furosemide is a "repurpose-able" small molecule therapeutics, that is safe, easily synthesized, handled, and stored, and is available in reasonable quantities worldwide.

Controlled Delivery of 80 mg Aerosol Furosemide Does Not Achieve Consistent Dyspnea Relief in Patients

PURPOSE

Aerosol furosemide may be an option to treat refractory dyspnea, though doses, methods of delivery, and outcomes have been variable. We hypothesized that controlled delivery of high dose aerosol furosemide would reduce variability of dyspnea relief in patients with underlying pulmonary disease.

METHODS

Seventeen patients with chronic exertional dyspnea were recruited. Patients rated recently recalled breathing discomfort on a numerical rating scale (NRS) and the multidimensional dyspnea profile (MDP). They then performed graded exercise using an arm-ergometer. The NRS was completed following each exercise grade, and the MDP was repeated after a pre-defined dyspnea threshold was reached. During separate visits, patients received either aerosol saline or 80 mg of aerosol furosemide in a randomized, double-blind, crossover design. After treatment, graded exercise to the pre-treatment level was repeated, followed by completion of the NRS and MDP. Treatment effect was defined as the difference between pre- and post-treatment NRS at end exercise, expressed in absolute terms as % Full Scale. "Responders" were defined as those showing treatment effect ≥ 20% of full scale.

RESULTS

Final analysis included 15 patients. Neither treatment produced a statistically significant change in NRS and there was no significant difference between treatments (p = 0.45). There were four "responders" and one patient whose dyspnea worsened with furosemide; two patients were responders with saline, of whom one also responded to furosemide. No adverse events were reported.

CONCLUSIONS

High dose controlled delivery aerosol furosemide was not statistically different from saline placebo at reducing exercise-induced dyspnea. However, a clinically meaningful improvement was noted in some patients.

The efficacy of nebulized furosemide and salbutamol compared with salbutamol alone in reactive airway disease: a double blind randomized, clinical trial

We undertook this randomized clinical trial to investigate whether adding furosemide to salbutamol could improve the peak expiratory flow rate (PEFR) and clinical signs of reactive airway disease (RAD) patients. Eligible 18- to 55-year-old patients were randomly divided into intervention and control groups. Patients received 5 mg of nebulized salbutamol and 40 mg of nebulized furosemide in the intervention group and 5 mg of nebulized salbutamol alone in the control group. Patients in both groups received 100 mg of methylprednisolone intravenously stat. Severity of the RAD was estimated before and 45 minutes after treatment in both groups. PEFR was estimated before treatment and at 15, 30, and 45 minutes later. Ninety patients were enrolled, 45 in each group. There were no significant differences between two groups regarding gender, mean age, and normalized PEFR. The baseline mean PEFR was not significantly different between groups (P = 0.58). A repeated measure analysis of variance revealed that the differences between the two treatments was significant (P = 0.0001) and the behavior of two treatments was not similar across the time (P = 0.001). Comparison of clinical severity of acute RAD revealed no significant differences between groups at the end of the trial (0.06). This study showed that adding nebulized furosemide to salbutamol in RAD patients improved PEFR.

Nebulized furosemide for the management of dyspnea: does the evidence support its use?

Dyspnea is a common and distressing symptom associated with multiple chronic illnesses and high levels of burden for individuals, their families and health care systems. The subjective nature dyspnea and a poor understanding of pathophysiological mechanisms challenge the clinician in developing management plans. Nebulized furosemide has been identified as a novel approach to dyspnea management. This review summarizes published studies, both clinical and experimental, reporting the use of nebulized furosemide. The search criteria yielded 42 articles published in the period 1988 to 2004. Although nebulized furosemide appeared to have a positive influence on dyspnea and physiological measurements, caution must be taken with the results primarily coming from small-scale clinical trials or observation trials. Despite the limitations of the studies reported, given the range of conditions reporting effectiveness of nebulized furosemide, further investigation of this potential novel treatment of dyspnea is warranted.

Furosemide inhalation in dyspnea of mustard gas-exposed patients: a triple-blind randomized study

Dyspnea is the hallmark symptom of some respiratory diseases such as chronic obstructive pulmonary disease and bronchiolitis and is a major reason for which these patients seek medical attention. We performed a randomized triple-blind controlled crossover clinical trial in which we compared the efficacy of inhaled furosemide (4 ml equal to 40 mg in 10 min) with placebo (4 ml of 0.9% saline solution) in 41 mustard gas-exposed patients. Dyspnea index, visual analog scale (VAS), and pulmonary function test results were obtained before and 4 h after treatments. Results showed that both furosemide and placebo significantly decreased VAS and dyspnea index and increased FEV(1), FVC, and FEV(1)/FVC, while there was no difference between the two drugs in these effects (p values .23, .61, .81, .36, and .27, respectively). Our results failed to address the previously reported effects of inhaled furosemide on dyspnea. In fact, we suggest that patients with a previous exposure to sulfur mustard, in which chronic bronchitis and bronchiolitis are the most suggested underlying mechanisms, may not benefit from furosemide to alleviate their dyspnea.

Effectiveness of nebulized furosemide added to nebulized salbutamol in children with acute asthma

BACKGROUND

Nebulized furosemide has been shown to be protective against bronchoconstricting stimuli.

METHODS

To investigate whether inhaled furosemide would exhibit an additional therapeutic effect in children with acute asthma we performed a double-blind, placebo-controlled study in which patients with acute asthma attack were randomized to receive either nebulized salbutamol (0.15 mg/kg) plus nebulized furosemide (10 mg/m(2)) or nebulized salbutamol (0.15 mg/kg) plus nebulized saline as placebo. In all patients, clinical asthma scores (CAS) were determined before and after drug administration. Peak expiratory flow rates (PEFR) were measured by a peak flow meter.

RESULTS

CAS and PEFR improved in both groups with nebulized salbutamol treatment. The CAS changed from 3.56 +/- 2.13 to 2.06 +/- 1.84 (p = 0.0001) in the study group and from 4.44 +/- 2.63 to 2.56 +/- 1.86 (p = 0.0003) in the control group. PEFR increased from 177.50 +/- 65.88 to 221.88 +/- 66.05 L/min in the first group (p = 0.0001) and from 183.13 +/- 51.73 to 218.13 +/- 60.25 in the second group (p = 0.0001).

CONCLUSION

Adding nebulized furosemide to nebulized salbutamol in pediatric patients experiencing an acute asthma attack did not produce greater improvement in clinical (p = 0.3829) or spirometric (p = 0.3839) parameters than nebulized salbutamol alone.

Effects of inhaled furosemide on exertional dyspnea in chronic obstructive pulmonary disease

The aim of this study is to investigate the effects of inhaled furosemide on the sensation of dyspnea produced during exercise in patients with stable chronic obstructive pulmonary disease (COPD). In a double-blind, randomized, crossover study we compared the effect of inhaled furosemide on dyspneic sensation during exercise testing with that of placebo. Spirometry and incremental and constant-load exercise testing were performed after inhalation of placebo or furosemide on 2 separate days in 19 patients with moderate or severe COPD. Subjects were asked to rate their sensation of respiratory discomfort using a 100-mm visual analog scale. There was significant improvement in mean FEV1 and FVC after inhalation of furosemide (p = 0.038 and 0.005, respectively) but not after placebo. At standardized exercise time during constant-load exercise testing but not during incremental exercise, the mean dyspneic visual analog scale score was lower after inhalation of furosemide compared with placebo (33.7 +/- 25.2 vs. 42.4 +/- 24.0 mm, respectively, p = 0.014). We conclude that inhalation of furosemide alleviates the sensation of dyspnea induced by constant-load exercise testing in patients with COPD and that there is significant bronchodilation after inhalation of furosemide compared with placebo in these patients.

Inhaled furosemide: a whole new mechanism of action

The use of aerosolized furosemide has been increasing throughout Mexico, primarily because of its mechanism and site of action as well as its local and systemic effect. We hypothesize that its effect on the respiratory system is totally independent from its diuretic activity and that it is primarily caused by its interaction with the chlorine channels. Furthermore, there is also evidence that furosemide induces prostaglandin synthesis, blocks the sodium-calcium pump, producing relaxation of the smooth muscle that narrows the airway and causes reduced nerve responsiveness to the Neurokinin A produced in acute asthma attacks.