Cardiac Glycosides

By Cardiologist on May 12th, 2011

Overview

Cardiac glycosides — namely, digoxin (GlaxoSmithKline’s Lanoxin/ Lanoxicaps, generics) — may be part of a treatment regimen for patients with right-ventricular failure and/or atrial arrhythmias. As with diuretics, the ACCP guidelines emphasize that physicians must carefully monitor pulmonary arterial hypertension patients on digoxin, especially if they already have impaired renal function.

Mechanism Of Action

Cardiac glycosides inhibit sodium/potassium adenosine triphosphatase (ATPase) in cardiac cells, resulting in stronger heart contractions. New data also demonstrated that some of the benefits of cardiac glycosides are due to their effect on noncardiac tissue. For instance, inhibiting sodium/potassium ATPase in vagal nerves can sensitize cardiac baroreceptors (pressure receptors), which in turn can reduce sympathetic tone of the heart. Inhibiting sodium/potassium ATPase in the kidney reduces sodium reabsorption, resulting in more sodium being delivered to the distal tubules and suppression of renin secretion. Some researchers have suggested that cardiac glycosides’ modification of the neurohormonal system is more beneficial than their positive inotropic effects.

Digoxin

Digoxin (GlaxoSmithKline’s Lanoxin/Lanoxicaps, generics) has been used as a treatment for the failing heart for many years. The agent acts on the sodium/potassium ATPase, strengthening cardiac contraction. Increased strength and efficiency of the heart improve the circulation and reduce the symptoms associated with right-heart failure in pulmonary arterial hypertension, including peripheral edema. The major side effects of digoxin occur at high doses and include cardiac arrhythmias, anorexia, nausea, vomiting, and neurological disturbances. The concomitant use of quinidine, verapamil, spironolactone, flecainide, propafenone, or amiodarone can increase serum digoxin levels and may increase the risk of digoxin toxicity. Researchers have determined that the risk of death increases above a digoxin level of l0 ng/mL, thus the need to monitor patients’ digoxin level. To date, no clinical studies have directly evaluated digoxin therapy in patients with pulmonary arterial hypertension.

This post has been viewed 942 times.

Posts Related to Cardiac Glycosides

Diuretics
Overview Diuretics are commonly used to treat pulmonary arterial hypertension patients with right-ventricular failure (e.g., those suffering from peripheral edema and/or ascites). The ACCP guidelines emphasize that the long-term management of pulmonary arterial hypertension patients requires the maintenance of near-normal intravascular volume via the use of diuretics in addition to reduced dietary salt intake. However, ...
Pulmonary Hypertension: Prostacyclin Analogues
Overview Prostacyclin (PGI2) is a metabolite of arachidonic acid and is endogenously produced by vascular endothelial cells. PGI2 is a potent vasodilator in both the systemic and pulmonary circulations and strongly inhibits platelet activation. A reduction in levels of PGI2 is thought to contribute to the pathogenesis of pulmonary arterial hypertension. Clinical studies over the ...
Pulmonary Arterial Hypertension: Current Therapies
Greater understanding of the etiology and pathophysiology of pulmonary arterial hypertension has led to significant advances in therapy for this disease. In addition, the publication of the American College of Chest Physicians' (ACCP's) evidence-based treatment guidelines in Chest in 2004 has aided physicians somewhat in treatment decisions. Nevertheless, treatment remains very complicated because patients respond ...
Calcium-Channel Blockers
Overview CCBs have been used to treat pulmonary hypertension, including pulmonary arterial hypertension, for many years. Randomized, controlled studies examining these agents in the treatment of pulmonary hypertension and chronic obstructive pulmonary disease have had positive outcomes. However, robust data highlighting the beneficial effects of this treatment approach for pulmonary arterial hypertension (the focus of ...
Vitamin K Antagonists
Overview For many years, experts in the pulmonary hypertension field have strongly recommended anticoagulant therapy to treat pulmonary arterial hypertension patients, particularly those without associated diseases for which contraindications may exist. This recommendation is based on the fact there is an increased risk of thrombosis and thromboembolism as a result of the sluggish pulmonary blood ...

Categorized under: Hypertension.
Tagged with: no tags.

Comments are closed.

High Blood Pressure / Hypertension

Hypertension Management