Gadoterate

Gadoterate meglumine is a gadolinium-based contrast agent (GBCA) used to enhance magnetic resonance imaging (MRI). It is a chelated gadolinium complex (gadolinium bound to meglumine) formulated as a macrocyclic compound. Marketed under the brand name Dotarem in many regions, it is produced by Guerbet. As a macrocyclic GBCA, gadoterate meglumine is among the more stable agents and is associated with a relatively low risk of gadolinium release.

Mechanism of action: The gadolinium chelate shortens the T1 relaxation time of nearby water protons, leading to increased signal on T1-weighted MRI and improved delineation of lesions, vascular structures, and areas of blood-brain barrier disruption.

Administration and dosing: The contrast is given by intravenous injection. The standard adult dose is 0.1 mmol/kg body weight (often corresponding to about 0.2 mL/kg of a 0.5 M solution). The exact dose depends on the indication and protocol. A saline flush follows the injection.

Indications: Gadoterate meglumine is used for contrast-enhanced MRI in a variety of settings, including detection and characterization of central nervous system lesions, imaging of abdominal and pelvic organs, and vascular and perfusion studies where MRI contrast is indicated.

Pharmacokinetics and safety: It is eliminated primarily by the kidneys, with a plasma half-life around 1.5 hours in patients with normal renal function. In renal impairment, clearance is reduced, increasing exposure and the theoretical risk of gadolinium retention. Macrocyclic agents like gadoterate meglumine have a lower risk of NSF than linear agents, but risk is not zero; current guidelines advise caution in patients with severe renal impairment (eGFR <30 mL/min/1.73 m2). Common adverse effects are mild and include nausea, headache, or injection-site reactions; serious hypersensitivity is rare. Extravasation can occur with IV administration.

Pregnancy and lactation: data are limited; use only if clearly needed. In lactation, small amounts may be excreted in milk; many guidelines permit continuation after discussion.

Regulatory status: Widely approved for diagnostic MRI in adults and children and available in multiple markets.