Landiolol, an ultra-short-acting injectable beta-blocker, has shown promise in rapidly controlling heart rate in patients with tachycardic atrial fibrillation (AF) without causing significant drops in blood pressure. This makes it a valuable option for emergency settings where rapid rate control is crucial.
Pharmacology and Clinical Studies
Landiolol shares similarities with esmolol but boasts faster pharmacokinetics, higher potency, and greater cardioselectivity. Animal models reveal landiolol's β1/β2-selectivity ratio is significantly higher than esmolol's (255:33 vs 216:30), translating to approximately seven-fold greater cardioselectivity. Clinically, landiolol is used in doses 5-10 times lower than esmolol, typically ranging from less than 5 mcg/kg/min up to 40 mcg/kg/min, compared to esmolol's 25 mcg/kg/min to 300 mcg/kg/min.
Pharmacodynamic characteristics observed in animal models have been confirmed in human trials. Studies involving healthy Caucasian volunteers demonstrated that landiolol had more pronounced effects on heart rate compared to esmolol, while esmolol exhibited a more prolonged hypotensive effect at equipotent doses. Further studies determined that a loading dose of 0.125 mg/kg for 1 minute, followed by an infusion titrated from 10 to 40 mcg/kg/min (up to 80 mcg/kg/min), is generally most effective.
Efficacy in Emergency Settings
A dose-ranging study evaluating landiolol's efficacy and safety in controlling heart rate in supraventricular tachycardia within an emergency department compared low, moderate, and high dose regimens. Response rates in patients with AF or atrial flutter (AFL) were 55.6%, 61.9%, and 69.2% for the low, moderate, and high dose groups, respectively. A subsequent study comparing the high-dose regimen (0.250 mg/kg loading + 80 mcg/kg/min) to placebo in AF/AFL patients showed that landiolol controlled tachycardia and significantly improved symptoms in 62.2% of patients, compared to only 2.3% in the placebo group. The incidence of adverse events was similar between the landiolol (8.0%) and placebo (14.3%) groups.
Experience in Caucasian Patients
Evaluations of landiolol in Caucasian patients with tachycardic AF/AFL in emergency departments tested two dosing regimens: a conventional scheme (100 mcg/kg/min loading infusion over 1 min, followed by 40 mcg/kg/min infusion) and an alternative scheme (40 mcg/kg/min continuous infusion, titrated up or down). Both regimens demonstrated similar efficacy, with 76% of AF patients achieving a target heart rate below 100 bpm. Symptom relief was reported by all patients (rapid heartbeat, shortness of breath, sweating, palpitation, and dizziness), and 90% reported relief from fatigue and irregular pulse. Mean arterial pressure remained stable (above -10% of baseline) during landiolol infusion. The dose response in Caucasian patients mirrored that of Asian patients treated for similar conditions.
