Droxidopa, an oral norepinephrine precursor, improves hemodynamic and renal alterations of portal hypertensive rats

Droxidopa in the Management of Hepatorenal Syndrome

PURPOSE

Hepatorenal syndrome (HRS) is renal dysfunction associated with the hemodynamic consequences of advanced liver disease and cirrhosis. HRS is associated with a high mortality, and there remain high failure rates with first-line therapy aimed at improving perfusion. We report the use of droxidopa, an oral norepinephrine precursor, to aid in the management of HRS-AKI refractory to first-line therapy.

SUMMARY

A 51-year-old Caucasian male with alcohol-related cirrhosis presented with 1-week history of pre-syncope and falls. He was found to have acute kidney injury meeting diagnostic criteria of HRS based on absence of identifiable contributing factors. After no response to volume expansion, medical management was initiated with midodrine and octreotide and eventually escalated to norepinephrine intravenous infusion. The patient's renal function and urine output improved initially on norepinephrine, but worsened when attempting to wean to a suitable outpatient regimen, becoming dependent upon norepinephrine. On day 13 of hospitalization, droxidopa was initiated at a dose of 100 mg three times daily and titrated to a dose of 400 mg three times daily. Norepinephrine infusion was weaned and discontinued on day 16 of hospitalization. The patient remained hemodynamically stable and was able to be discharged on droxidopa 400 mg three times daily, midodrine 20 mg three times day, and octreotide 200 mcg three times daily.

CONCLUSION

Droxidopa, an oral norepinephrine precursor, presents a novel adjunctive agent for management of HRS refractory to first-line medical management.

Neurogenic Orthostatic Hypotension: State of the Art and Therapeutic Strategies

Neurogenic orthostatic hypotension (nOH) is a subtype of orthostatic hypotension in which patients have impaired regulation of standing blood pressure due to autonomic dysfunction. Several primary and secondary causes of this disease exist. Patients may present with an array of symptoms making diagnosis difficult. This review article addresses the epidemiology, pathophysiology, causes, clinical features, and management of nOH. We highlight various pharmacological and non-pharmacological approaches to treatment, and review the recent guidelines and our approach to nOH.

Pharmacologic Management of Portal Hypertension

Terlipressin, somatostatin, or octreotide are recommended as pharmacologic treatment of acute variceal hemorrhage. Nonselective β-blockers decrease the risk of variceal hemorrhage and hepatic decompensation, particularly in those 30% to 40% of patients with good hemodynamic response. Carvedilol, statins, and anticoagulants are promising agents in the management of portal hypertension. Recent advances in the pharmacologic treatment of portal hypertension have mainly focused on modifying an increased intrahepatic resistance through nitric oxide and/or modulation of vasoactive substances. Several novel pharmacologic agents for portal hypertension are being evaluated in humans.

Dose-dependency of clonidine's effects in ascitic cirrhotic rats: comparison with α1-adrenergic agonist midodrine

BACKGROUND & AIMS

Sympathetic nervous system (SNS) activation decreases response to diuretics, but both α1-adrenoceptor agonists and sympatholytic α2-adrenoceptor agonists are recommended in the management of ascitic cirrhosis. We intend to compare the effects of increasing doses of clonidine (α2-agonist) vs. midodrine (α1-agonist) in advanced cirrhosis.

METHODS

Renal function, mean arterial pressure (MAP), and hormonal status were measured in rats with ascitic cirrhosis due to 13-week CCl(4) administration (groups G1-G5), in control rats (Gc), and in rats with ascitic cirrhosis untreated (G6) or treated with daily diuretics (0.5 mg/kg furosemide plus 2 mg/kg K(+) -canrenoate during the 11(th) -13(th) weeks of CCl(4)) (G7). G1-G5 cirrhotic rats received daily, during the 11(th)-13(th) CCl(4) weeks: clonidine 0.3 μg only (G1), diuretics + clonidine 0.2 (G2), 0.5 (G3) or 1 μg (G4), and diuretics + midodrine 1 mg/kg b.w. (G5).

RESULTS

Cirrhotic rats in G1 or G2 had higher glomerular filtration rate, renal plasma flow and natriuresis than cirrhotic rats treated with diuretics (G7) (all P < 0.05). The addition of clonidine 0.2 μg to diuretics (G2 vs. G7) reduced serum norepinephrine (169 ± 71 ng/L vs. 523 ± 88 ng/L) and plasma renin activity (12 ± 3 ng/ml/h vs. 25 ± 5 ng/ml/h) (all P < 0.05). Midodrine did not improve the renal performance in ascitic rats treated with diuretics. In comparison to absolute cirrhotic controls (G6), MAP was lower in G4 and higher in G5 (all P < 0.05).

CONCLUSION

Low-dose α2-agonists improve natriuresis and reduce SNS function and hyper-aldosteronism without affecting arterial pressure in experimental ascitic cirrhosis treated with diuretics.

The Treatment of Hepatorenal Syndrome

Hepatorenal syndrome (HRS) is a severe complication that often occurs in patients with cirrhosis and ascites. HRS is a functional renal failure that develops mainly as a consequence of a severe cardiovascular dysfunction which is characterized by an extreme splanchnic arterial vasodilation and a reduction of cardiac output. HRS may develop in two clinical types: as an acute and rapidly progressive renal failure (AKI-HRS) or as chronic and not progressive renal failure (CKD-HRS). Several small studies and some randomized control studies have been published on the use of terlipressin plus albumin in the treatment of HRS, mainly on AKI-HRS. Terlipressin plus albumin was shown to improve renal function in almost 35-45% of patients with AKI-HRS, as well as to improve short-term survival in these patients. Terlipressin was most commonly used by intravenous boluses moving from an initial dose of 0.5-1 mg every 4 h to 3 mg every 4 h in the case of a nonresponse. In other studies, terlipressin was also given by continuous intravenous infusion. Thus, the best way to administer terlipressin in the treatment of HRS has not yet been defined. α-Adrenergic drugs, such as intravenous norepinephrine or oral midodrine plus subcutaneous octreotide, administered with albumin have also been used in the treatment of AKI-HRS, with promising results. However, we need further studies in order to define whether they can represent a real therapeutic alternative. In conclusion, available data are sufficient to state that the use of terlipressin plus albumin has really changed the management of HRS. Nevertheless, some crucial unsolved issues still exist, in particular: (a) how to predict nonresponse to treatment, (b) how to manage nonresponse to treatment and (c) how to consider the response in those patients who are candidates for liver transplant in the priority allocation process.

The renal effects of droxidopa are maintained in propranolol treated cirrhotic rats

BACKGROUND & AIMS

Droxidopa improves hemodynamic and renal alterations of cirrhotic rats without changing portal pressure. We aimed to evaluate the effects of a combined treatment with droxidopa and non-selective beta-blockers or statins in order to decrease portal pressure, while maintaining droxidopa beneficial effects.

METHODS

Acute studies combining droxidopa with carvedilol, propranolol or atorvastatin in four-week bile-duct ligated (BDL) rats and a chronic study combining propranolol and droxidopa for 5 days in CCl4 -cirrhotic rats were performed. Hemodynamic values were registered and biochemical parameters from blood and urine samples analyzed.

RESULTS

Bile-duct ligated rats treated with carvedilol + droxidopa showed no changes in mean arterial pressure (MAP) and portal pressure (PP) compared to vehicles. Atorvastatin + droxidopa combination also failed to reduce PP, but maintained the beneficial increase in MAP and superior mesenteric artery resistance (SMAR) and decrease in blood flow (SMABF) caused by droxidopa. In contrast, the acute administration of propranolol + droxidopa significantly reduced PP maintaining a mild increase in MAP and improving, in an additive way, the decrease in SMABF and increase in SMAR caused by droxidopa. This combination also preserved droxidopa diuretic effect. When chronically administered to CCl4 -cirrhotic rats, propranolol + droxidopa caused a decrease in PP, a significant reduction in SMABF and an increase in SMAR. The combination did not alter liver function and droxidopa diuretic and natriuretic effect, and even improved free water clearance.

CONCLUSION

Droxidopa could be effective for the renal alterations of cirrhotic patients on propranolol therapy and the combination of both drugs may balance the adverse effects of each treatment.