Gadopentetate dimeglumine (Magnegita, Magnevist) is a radiocontrast agent that is used during MR imaging diagnostic procedures to visualize vascular lesions of the brain, spine, and other body parts.

Gadopentetate dimeglumine Uses:

• Body imaging:

  • MRI agent to visualize body lesions with abnormal vascularity in adults and children of 2 or more than  years of age.

• CNS imaging:

  • MRI agent to visualize CNS lesions with abnormal vascularity in the spine,brain, and associated tissues in adults and children of 2 years or more than 2 years of age.

• Head and neck imaging:

  • MRI agent to visualize head and neck lesions with abnormal vascularity in adults and children within age of 2 years or more than 2 years of age.

• Off Label Use of Gadopentetate in Adults:

  • Magnetic resonance angiography (MRA)

Gadopentetate dimeglumine (Magnegita, Magnevist) dose in Adults

Gadopentetate dimeglumine (Magnegita, Magnevist) dose in the Body, CNS, head, and neck imaging:

• IV: 0.1 mmol per kg (0.2 mL per kg)

Note: Dosing for patients more than 130 kg (286 pounds) has not been studied.

Gadopentetate dimeglumine (Magnegita, Magnevist) dose in Childrens

Note: Dosing presented in mL per kg and mmol per kg; use caution. Parenteral solution contains 0.5 mmol per mL of gadopentetate dimeglumine.

Gadopentetate dimeglumine Dose in the Body, CNS, head, and neck magnetic resonance imaging:

• Children ≥2 years and Adolescents:

  • IV: 0.2 mL per kg (0.1 mmol per kg);
  • The imaging must be completed within 1 hour of injection.

Note: Dosing for patients more than 130 kg (286 pounds) has not been studied.

Pregnancy Category: C

• Gadopentetate dimeglumine crosses over the placenta
• Contrast agents containing gadolinium-based elements in pregnancy should not be used.
• Additionally, it is important to only consider using a contrast agent if the information required from an MRI study can't be obtained without using one. This cannot be delayed until after delivery.
• If it is proven to significantly improve diagnostic performance, and is expected that it will improve fetal or maternal outcomes, a gadolinium-based contrast agents with MRI might be considered for pregnancy.
• Agents that pose a low risk of developing nephrogenic fibrosis are recommended to be administered at the lowest possible dose.

Gadopentetate dimeglumine use during breastfeeding:

• Breast milk contains gadopentetate dimeglumine.
• Subjects had different maximum milk concentrations and times of maximum milk concentrates.
• However, gadolinium concentrations varied over time and increased with maternal dose and volume of milk produced.
• Breastfeeding may continue after discontinuation due to the low expected excretion of breast milk and low absorption by infants' GI tract.
• They can store and pump milk before the procedure, then bottle-feed the milk stored during that time.
• Theoretically speaking, milk's taste could be affected if it contains contrast media.
• Women who choose to temporarily stop breastfeeding can express breast milk or discard it from one breast for 12-24 hours after administration of contrast media.
• According to the manufacturer breastfeeding during therapy is a decision that should be made after considering the risks to infants and the benefits to mothers.

Gadopentetate dimeglumine (Magnegita) Dose in Kidney Disease:

• GFR >30 mL/minute/1.73 m²:

  • The manufacturer's labeling doesn't provide any dosage adjustments; use with caution. The risk for NSF development increases as renal function decreases.

• GFR <30 mL/minute/1.73 m²:

  • Its use contraindicated.

• Hemodialysis:

  • If administered to patients already receiving hemodialysis, consider prompt hemodialysis following exposure (eg, within 3 hours).
  • Data has been shown hemodialysis enhances gadolinium elimination with average gadolinium excretory rates of 78 percent, 96 percent, and 99 percent in the first, second, and third hemodialysis sessions, respectively.

• Peritoneal dialysis:

  • Likely to be less efficient at clearing gadolinium.

Dose in Liver disease:

The manufacturer’s labeling doesn't provide any dosage adjustments; does not undergo significant hepatic metabolism.

Side Effects of Gadopentetate dimeglumine:

• Central nervous system:

  • Headache
  • Sensation of cold
  • Dizziness

• Gastrointestinal:

  • Nausea

Contraindications to Gadopentetate dimeglumine:

• Chronic severe kidney disease (GFR lower than 30 mL/minute per 1.73m2)
• Acute kidney injury
• Hypersensitivity to gadopentetate or any component of this formulation.
• Canadian labeling: Additional contraindications not in US labeling
  • Due to their immature renal function, neonates can live up to 4 weeks.

Warnings and precautions

• Extravasation:

  • Monitor infusion site.
  • Avoid extravasation.
  • Vesicant: Before and during administration, ensure that the needle/catheter/line is correctly placed.
  • There have been rare cases of skin and soft tissue necrosis as well as thrombosis and fasciitis at the injection site.
  • Sometimes, phlebitis or thrombophlebitis can be seen within 24 hours. Supportive treatment is available.

• Gadolinium retention:

  • Gadolinium can be retained in bone, skin, liver, spleen and kidneys for many months to years.
  • The bone has the highest concentration and longest retention time.
  • Linear GBCAs (gadodiamide and gadoversetamide > gadoxetate disodium, gadopentetate dimeglumine, and gadobenate dimeglumine) result in more retention than macrocyclic GBCAs ( gadobutrol,gadoterate meglumine, and gadoteridol).
  • Patients with normal renal function may be more at risk of gadolinium retention.
  • These include patients who require multiple lifetime doses, pregnant or pediatric patients, as well as patients with inflammatory conditions.
  • Patients with impaired renal function have had to deal with the clinical and pathologic consequences of gadolinium storage in their skin and other organs.
  • Rarely, however, have they experienced skin problems that were not related to renal impairment.
  • Gadolinium retention in the brain and in patients with normal renal function has not been shown to have any adverse effects.
  • Minimize repetitive GBCA imaging studies.

• Hypersensitivity reactions

  • Sometimes, delayed reactions can occur within hours after administration.
  • Hypersensitivity, including anaphylactic reactions (rare), may occur; appropriate equipment (eg, ventilator) and emergency medications (eg, epinephrine) should be available during use.
  • Patients who have had bronchial asthma or allergic reactions in the past may be at higher risk of developing hypersensitivity reactions. Be careful.

• Nephrogenic systemic Fibrosis: [US Boxed Warn]

  • Patients with renal impairment may be at greater risk from gadolinium-based contrast agents.
  • Avoid using GBCA enhanced imaging unless it is absolutely necessary for diagnostic purposes.
  • Patients with severe, acute renal disease or acute kidney injury (GFR 30mL/minute/1.73m2) are not recommended to use this medication.
  • Patients with moderate or chronic kidney disease have a lower risk (GFR 30 to 60 mL/minute/1.73m2), and patients with mild chronic renal disease have a much lower risk (GFR 60-89 mL/minute/1.73m2).
  • NSF is a potentially fatal condition that affects skin, muscles, and internal organs.
  • Before administering medication, all patients should be tested for kidney dysfunction.
  • Consider prompt hemodialysis for patients on hemodialysis.
  • Patients at high risk for NSF should not exceed the recommended dose and allow enough time (ie several half-lives), for elimination before re-administration.
  • Avoidance of readministration is preferable.

• Renal impairment

  • Patients with renal impairment have experienced a dose-dependent worsening or acute renal failure, usually within 48 hours of administration.
  • Before using, evaluate the renal function of patients with kidney impairment; consider following-up monitoring.
  • Patients with severe kidney impairment should be cautious.
  • Contraindicated for patients with acute kidney injury and chronic, severe renal impairment (GFR 30mL/minute/1.73m2).

Monitoring parameters:

• Patient and injection site should be monitored for signs of hypersensitivity for several hours following injection;
• monitor injection site for extravasation;
• renal function (prior to administration);
• short- and long-term monitoring of signs and symptoms of NSF (eg, hardening and/or tightening of skin, joint stiffness,burning, itching, swelling, deep hip or rib bone)

How to administer Gadopentetate dimeglumine?

IV:

• The dose should be administered at a rate not to exceed 10 mL per 15 seconds.
• Complete imaging procedure within 1 hour of injection. Following administration, flush line with NS 5 mL.
• Vesicant; ensure proper needle or catheter placement prior to and during infusion; avoid extravasation.

Extravasation management:

• If extravasation occurs, stop infusion immediately and disconnect; remove needle/cannula; elevate extremity.
• Aspiration of extravasated contrast media is not recommended.
• Information conflicts regarding the use of hyaluronidase; the American College of Radiology (ACR) Manual on Contrast Media does not recommend hyaluronidase in the management of contrast media extravasation; other sources suggest its utility in extravasation management.

If using hyaluronidase: Intradermal or SubQ:

• Inject a total of 1 to 1.7 mL (15 units/mL) as five separate 0.2 to 0.3 mL injections (using a 25-gauge needle) into the area of extravasation at the leading edge in a clockwise manner or injection of a total of 5 mL (150 units per mL) as five separate 1 mL injections around the extravasation site has been also used successfully.

Mechanism of action of Gadopentetate dimeglumine (Magnegita) :

• An external magnetic field can induce a strong local magnetic field in gadopentetate-exposed tissues. 
• The local magnetism causes water protons to be disrupted in the area, which results in a change of proton density and spin characteristics that can be detected using the imaging device.

Distribution:

• It doses not cross intact blood-brain barrier; distribution half-life: 0.2 ± 0.13 hours

Half-life elimination:

• 1.6 ± 0.13 hours
• CrCl ≥60 mL/minute: 2.6 ± 1.2 hours
• CrCl 30 to <60 mL/minute: 4.2 ± 2 hours
• CrCl <30 mL/minute: 10.8 ± 6.9 hours

Excretion:

• Urine (~91 percent as gadopentetate within 24 hours)

International Brand Names of Gadopentetate dimeglumine:

• Magnetolux
• Magnevistan
• Magnilek
• Megaray
• Tomovist
• Viewgam
• Magnevist
• Gadomin
• Magnegita
• Magnetol

Gadopentetate dimeglumine Brand Names in Pakistan:

• Magnevista