gadopentetaat

Gadopentetate, commonly known as gadopentetate dimeglumine, is a gadolinium-based contrast agent used to enhance magnetic resonance imaging (MRI). It is a chelated gadolinium compound that shortens T1 relaxation times, increasing signal in tissues after intravenous administration.

Chemistry: Gadopentetate dimeglumine is a linear, ionic gadolinium chelate formed from gadolinium bound to diethylenetriaminepentaacetic acid (DTPA) with two meglumine counterions. Its linear structure is associated with relatively higher risk of gadolinium release compared with macrocyclic agents.

Medical uses: It is indicated to improve delineation of lesions and vessels in MRI, including central nervous system tumors, inflammatory or infectious processes, and metastatic disease, as well as for vascular imaging in some protocols. It is not used for therapeutic purposes.

Administration and dosing: The agent is given by intravenous injection. A typical dose is 0.1 mmol per kilogram of body weight, though dosing may vary by protocol and indication. It is used with standard MRI sequences and may be repeated if clinically warranted.

Safety and adverse effects: Most patients tolerate gadopentetate well, but adverse events such as nausea, headache, or injection-site reactions can occur. Serious allergic reactions are uncommon. In severe kidney impairment, gadolinium-containing contrast agents carry a risk of nephrogenic systemic fibrosis, particularly with linear agents; macrocyclic agents pose lower risk. Repeated exposure has been associated with gadolinium deposition in brain tissue; the clinical significance is not fully established. Use in pregnancy is guided by risk-benefit considerations.

Pharmacokinetics: After intravenous administration, gadopentetate has a plasma half-life of about 1.5 hours in individuals with normal renal function and is excreted largely unchanged by the kidneys.

Regulatory status and overview: Gadopentetate dimeglumine has been approved for diagnostic MRI use in many regions and remains one of the long-standing GBCAs in clinical practice, with usage patterns influenced by safety considerations and evolving guidelines.