Gadoteric Acid

Approved Indications:

• Contrast agent for magnetic resonance imaging (MRI), primarily for contrast enhancement of the central nervous system (brain and spinal cord).
• Visualization and characterization of lesions such as tumors, inflammatory processes, vascular abnormalities, and demyelinating diseases.
• Imaging of liver, kidneys, and musculoskeletal system where detailed soft tissue differentiation is necessary.
• Evaluation of blood-brain barrier integrity and other soft tissue abnormalities.

Off-label/Clinically Accepted Uses:

• Contrast enhancement in MR angiography (MRA) for vascular imaging.
• Follow-up imaging of known lesions or pathologies.
• Other body parts imaging where gadolinium-based contrast agents are clinically indicated.

Adults and Pediatrics:

• Recommended Dose: 0.1 mmol/kg body weight, typically administered as 0.2 mL/kg of a 0.5 mmol/mL solution.
• Route of Administration: Intravenous injection, usually as a bolus.
• Injection Rate: Injected over approximately 15 to 60 seconds, followed by a saline flush.
• Repeat Dosing: Additional doses may be administered if clinically necessary, with appropriate intervals to allow elimination (usually at least 24 hours).

Special Populations:

• Renal Impairment: Dose adjustment or avoidance recommended in patients with severe renal impairment due to increased risk of nephrogenic systemic fibrosis (NSF).
• Elderly: No specific dose adjustment; monitor renal function carefully.
• Pediatrics: Use the same weight-based dosing; safety established in children.

Gadoteric acid is a gadolinium-based contrast agent (GBCA) composed of gadolinium ion chelated by a macrocyclic ligand (DOTA). It acts by shortening the T1 relaxation time of nearby water protons during MRI scanning. The paramagnetic gadolinium ion enhances signal intensity on T1-weighted images, improving visualization of tissues with abnormal vascularity or disrupted blood-brain barrier. The macrocyclic chelation provides high stability, reducing free gadolinium release and minimizing toxicity.

• Absorption: Administered intravenously; bioavailability is 100%.
• Distribution: Distributes rapidly in the extracellular fluid; negligible plasma protein binding.
• Metabolism: Not metabolized; remains intact in the body.
• Elimination: Eliminated primarily by renal excretion via glomerular filtration.
• Half-life: Approximately 1.5 hours in patients with normal renal function.
• Excretion: About 95% excreted unchanged in urine within 24 hours.

• Pregnancy: FDA Pregnancy Category C. Animal reproduction studies have shown no direct teratogenic effects, but adequate human data are lacking. Use only if clearly needed.
• Lactation: Unknown if gadoteric acid is excreted in human milk; caution advised. Breastfeeding mothers should consult healthcare professionals before undergoing contrast MRI.

• Primary Class: MRI Contrast Agent
• Subclass: Gadolinium-based contrast agent (Macrocyclic, ionic)

• Known hypersensitivity to gadoteric acid or any formulation excipients.
• Severe renal impairment (glomerular filtration rate <30 mL/min/1.73 m²) unless benefits outweigh risks.
• History of nephrogenic systemic fibrosis (NSF).

• Nephrogenic Systemic Fibrosis (NSF): Serious condition mainly seen in patients with severe renal impairment exposed to GBCAs; use with caution or avoid in such patients.
• Hypersensitivity Reactions: Rare but may occur; facilities for emergency treatment should be available.
• Renal Function: Assess renal function prior to administration in at-risk populations (elderly, diabetics).
• Gadolinium Retention: Small amounts may remain in brain and tissues after repeated use; clinical significance unclear.
• Pregnancy and Lactation: Use only when clearly indicated.
• Extravasation: Careful IV administration to prevent tissue irritation.

Common:

• Headache
• Nausea
• Injection site reactions (pain, swelling)
• Dizziness
• Taste disturbances (metallic taste)

Serious or Rare:

• Anaphylactic or anaphylactoid reactions
• Nephrogenic systemic fibrosis (rare, mostly in renal impairment)
• Hypotension
• Local tissue irritation or necrosis due to extravasation

• No significant drug-drug interactions known, as gadoteric acid is not metabolized by liver enzymes.
• No known food or alcohol interactions.
• Caution advised with concomitant nephrotoxic drugs to avoid renal toxicity.

• Emphasis on avoiding use in patients with severe renal impairment to minimize NSF risk.
• Regulatory guidance favors macrocyclic GBCAs like gadoteric acid over linear agents due to greater stability and lower gadolinium retention.
• Guidelines recommend the lowest effective dose and limiting repeated administration.
• Ongoing monitoring of gadolinium retention effects, though no definitive adverse clinical outcomes reported to date.

• Store at controlled room temperature between 20°C and 25°C (68°F to 77°F).
• Protect from freezing and light exposure.
• Keep container tightly closed.
• Use promptly after opening according to manufacturer’s guidelines.
• Single-use vials should not be reused; discard unused portion appropriately.