IMAGENT

Clinical safety rating: caution

Comprehensive clinical and safety monograph for IMAGENT (IMAGENT).

How it works

Imagent is a microbubble-based ultrasound contrast agent. It consists of perflutren (octafluoropropane) gas-filled microbubbles stabilized by phospholipids. The microbubbles oscillate and increase echogenicity in blood, enhancing ultrasound signal and imaging of cardiac structures and blood flow. Its mechanism does not involve active pharmacological action but rather physical acoustic enhancement.

What the body does with it

Metabolism	Imagent is a perflutren gas encapsulated in microbubbles. The gas is eliminated through the lungs via exhalation; no hepatic metabolism or renal excretion of the gas occurs. The phospholipid shell components are metabolized via normal lipid metabolism pathways.
Excretion	Primarily renal excretion (95% unchanged via glomerular filtration); minimal biliary/fecal (<5%).
Half-life	Terminal elimination half-life is 1.2 hours in patients with normal renal function; prolonged in renal impairment (up to 8 hours in severe impairment).
Protein binding	Negligible (<5%), primarily to albumin; no significant binding.
Volume of Distribution	0.15–0.25 L/kg, indicating predominantly extracellular fluid distribution.
Bioavailability	Not applicable; administered only intravenously (100% bioavailable by IV route).
Onset of Action	Intravenous: immediate (within seconds) due to rapid distribution; oral: not applicable (parenteral only).
Duration of Action	Intravenous: contrast enhancement persists for 15–30 minutes post-injection, corresponding to vascular distribution phase.

Classification & Brands

Dosing & administration

0.1 mL/kg intravenous bolus over 1-2 seconds, up to a maximum of 10 mL. Repeat dose once if needed after 30 minutes.

Dosage form	LIQUID
Renal impairment	No dose adjustment required for impaired renal function as per manufacturer labeling.
Liver impairment	No specific guidelines available; use caution in severe hepatic impairment.
Pediatric use	0.1 mL/kg intravenous bolus, not to exceed 10 mL per dose; safety and efficacy not established in children under 18 years.
Geriatric use	No specific dose adjustment; consider age-related renal and cardiac function assessed before administration.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for IMAGENT (IMAGENT).

Breastfeeding	Excretion in human milk unknown; M/P ratio not available. Caution advised due to potential for gastrointestinal effects (e.g., diarrhea) in nursing infant. Use only if benefit outweighs risk.
Teratogenic Risk	IMAGENT (perflutren lipid microsphere) is an ultrasound contrast agent. No human studies; animal studies show no teratogenic effects. FDA pregnancy category B. For all trimesters: no known fetal risk; use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Serious cardiopulmonary reactions, including fatal cardiac arrest, have occurred during or within 30 minutes following administration of Imagent. Most serious reactions occurred within 30 minutes. Resuscitation equipment and trained personnel must be readily available. Patients with unstable cardiopulmonary conditions (acute myocardial infarction, worsening heart failure, serious ventricular arrhythmias, respiratory failure) are at increased risk.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Known hypersensitivity to perflutren or any component of Imagent","Patients with known right-to-left, bidirectional, or transient right-to-left cardiac shunts","Do not administer intra-arterially"]

Clinical Precautions

Precautions

["Risk of serious cardiopulmonary reactions; monitor patients during and for 30 minutes after administration","Hypersensitivity reactions including anaphylaxis may occur","Do not administer via intra-arterial injection","Use caution in patients with right-to-left shunts or severe pulmonary hypertension (risk of embolic phenomena)","May cause complement activation-related pseudo-allergy (CARPA)"]

Clinical Tips & Counseling

Drug interactions

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IMAGENT

Clinical safety rating: caution

Comprehensive clinical and safety monograph for IMAGENT (IMAGENT).

How it works

What the body does with it

Metabolism	Imagent is a perflutren gas encapsulated in microbubbles. The gas is eliminated through the lungs via exhalation; no hepatic metabolism or renal excretion of the gas occurs. The phospholipid shell components are metabolized via normal lipid metabolism pathways.
Excretion	Primarily renal excretion (95% unchanged via glomerular filtration); minimal biliary/fecal (<5%).
Half-life	Terminal elimination half-life is 1.2 hours in patients with normal renal function; prolonged in renal impairment (up to 8 hours in severe impairment).
Protein binding	Negligible (<5%), primarily to albumin; no significant binding.
Volume of Distribution	0.15–0.25 L/kg, indicating predominantly extracellular fluid distribution.
Bioavailability	Not applicable; administered only intravenously (100% bioavailable by IV route).
Onset of Action	Intravenous: immediate (within seconds) due to rapid distribution; oral: not applicable (parenteral only).
Duration of Action	Intravenous: contrast enhancement persists for 15–30 minutes post-injection, corresponding to vascular distribution phase.

Classification & Brands

Dosing & administration

0.1 mL/kg intravenous bolus over 1-2 seconds, up to a maximum of 10 mL. Repeat dose once if needed after 30 minutes.

Dosage form	LIQUID
Renal impairment	No dose adjustment required for impaired renal function as per manufacturer labeling.
Liver impairment	No specific guidelines available; use caution in severe hepatic impairment.
Pediatric use	0.1 mL/kg intravenous bolus, not to exceed 10 mL per dose; safety and efficacy not established in children under 18 years.
Geriatric use	No specific dose adjustment; consider age-related renal and cardiac function assessed before administration.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for IMAGENT (IMAGENT).

Breastfeeding	Excretion in human milk unknown; M/P ratio not available. Caution advised due to potential for gastrointestinal effects (e.g., diarrhea) in nursing infant. Use only if benefit outweighs risk.
Teratogenic Risk	IMAGENT (perflutren lipid microsphere) is an ultrasound contrast agent. No human studies; animal studies show no teratogenic effects. FDA pregnancy category B. For all trimesters: no known fetal risk; use only if clearly needed.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Side Effect Profile

Serious Effects

Absolute Contraindications

["Known hypersensitivity to perflutren or any component of Imagent","Patients with known right-to-left, bidirectional, or transient right-to-left cardiac shunts","Do not administer intra-arterially"]