Myocardial Toxicity in a Group of Greyhounds Administered Ractopamine

Abstract

Ractopamine, a synthetic β(2)-adrenoceptor agonist, is widely used as a feed additive in the United States to promote a reduction in body fat and enhance muscle growth in cattle, pigs, and turkeys. It has the potential for illegal use in show and racing animals because it may affect performance via its β-adrenergic agonist properties or anabolic activities. Nine greyhounds were orally administered 1 mg/kg of ractopamine to investigate the ability to detect the drug in urine. Postdosing, 7 of 9 dogs developed cardiac arrhythmias and had elevated troponin levels indicating myocardial damage. One dog necropsied 4 days postdosing had massive myocardial necrosis, mild to focally moderate skeletal muscle necrosis, and widespread segmental arterial mediolysis. A second dog necropsied 17 days postdosing had mild myocardial necrosis and fibrosis. Scattered arteries exhibited segmental medial and perimedial fibromuscular dysplasia. This is the first reported case of arterial, cardiac, and skeletal muscle damage associated with ractopamine.

Adverse Effects from Clenbuterol and Ractopamine on Nematode Caenorhabditis elegans and the Underlying Mechanism

“…With the increased use of internet sales, the internet has made this even banned product to be readily accessible for the aim of weight loss or dieting addition [2]. Ractopamine, a synthetic β2-adrenoceptor agonist, is now widely used as a feed additive in the United States to promote a reduction in body fat and to enhance muscle growth in cattle, pigs, or turkeys [5].…”

“…Moreover, at least the toxic effects on cardiovascular systems (such as tachycardia and hypertension) are considered to be of clinical relevance [7]–[9]. More recently, it was further reported that ractopamine administration might cause the myocardial toxicity in dogs [5].…”

Treatment and resolution of zilpaterol hydrochloride toxicity in aQuarterHorse gelding

“…A prospective study in Greyhounds found that 7 out of 9 dogs administered ractopamine developed arrhythmias and elevations in cardiac troponin I (Yaeger et al . ).…”

Ractopamine in particulate matter emitted from beef cattle feedyards and playa wetlands in the Central Plains

“…As a nonselective beta agonist, ractopamine has affinity for and efficacy at both the b1 (predominant in cardiac tissue) and b2 (predominant in muscle) receptor subtypes (Baker 2005); there is also evidence that ractopamine can interact with other receptors in vitro (trace amine-associated receptor 1, Liu et al 2014;estrogen receptor a, McRobb et al 2014). Acute myocardial toxicity has been reported in dogs following a single oral 1 mg/kg dose (Yaeger et al 2012). Acute myocardial toxicity has been reported in dogs following a single oral 1 mg/kg dose (Yaeger et al 2012).…”