Comparative Pharmacology
Head-to-head clinical analysis: DEFINITY versus DEFINITY RT.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DEFINITY versus DEFINITY RT.
DEFINITY vs DEFINITY RT
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Definity (perflutren) is an ultrasound contrast agent composed of lipid-coated microspheres filled with perfluoropropane gas. It enhances ultrasound signal by increasing backscatter from blood, improving visualization of cardiac chambers and blood flow.
Definity RT is a perflutren lipid microsphere suspension that acts as an ultrasound contrast agent. The microspheres consist of perfluoropropane gas encapsulated in a lipid shell. When administered intravenously, they oscillate in an ultrasound field, enhancing the backscatter of ultrasound waves, thereby improving visualization of cardiac chambers and blood flow.
0.5 mL as a bolus intravenous injection, followed by a 10 mL saline flush. A second dose of 0.5 mL may be administered if clinically necessary. Alternatively, a 1.3 mL infusion diluted in 50 mL saline administered at 4 mL/min intravenously.
10 µL/kg intravenously as a bolus injection; may repeat once after 30 minutes if needed.
None Documented
None Documented
The terminal half-life of the perfluoropropane gas is approximately 1.3 minutes (rapid clearance from the blood pool via exhalation). The lipid components have a half-life of approximately 6 hours.
Terminal elimination half-life of perfluoropropane gas is approximately 1.3 minutes; clinical contrast enhancement persists for 3-5 minutes post-injection.
Eliminated primarily via exhalation (perfluoropropane gas) and renal excretion (shell components). Approximately <1% of the administered dose is excreted unchanged in urine over 24 hours; the lipid shell components are metabolized via endogenous pathways with biliary/fecal elimination.
Primarily eliminated via the lungs as exhaled perfluoropropane gas; renal excretion of the lipid shell components is negligible (<1%).
Category C
Category C
Ultrasound contrast agent
Ultrasound contrast agent