Omniscan

Omniscan is a contrast agent used for MRI procedures.

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Indications Omniscan

It is used exclusively for diagnostics. It is used for MRI of the spine and skull, as well as for MRI of various parts of the body, including the head, neck, sternum (including the heart) and limbs. The injection of the drug allows for examination of the peritoneum and retroperitoneal area together with the pelvis (liver, bladder, pancreas, prostate and kidneys), mammary glands, muscle and skeletal structure, and blood vessels (angiography procedure).

Omniscan enables visualization of various lesions and abnormal formations, which facilitates differentiation between pathological and healthy tissues.

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Release form

The substance is released in the form of an injection liquid, in vials with a capacity of 10, 15 or 20 ml. The package contains 10 such vials.

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Pharmacodynamics

Omniscan is a non-ionic substance used for MRI. Its paramagnetic properties allow for contrast enhancement during MRI procedures. The drug contains gadodiamide, which primarily affects the T1 relaxation time.

The introduction of the medicinal element leads to an increase in the signal from those areas where there is dysfunction of the BBB associated with its damage due to pathological damage. The drug provides more voluminous information content of images in comparison with the information obtained during MRI before contrast enhancement. The substance often achieves the optimal level of increased contrast during the first minutes after injection (taking into account the type of tissue and damage). This effect often persists for 45 minutes after the injection.

The drug helps to potentiate contrast and simplify the visualization of lesions and abnormal areas inside different parts of the body, including the central nervous system. The drug cannot pass through the BBB. The use of Omniscan in case of BBB dysfunction potentiates the visualization of lesions with abnormal vascularization and pathological changes (or those that lead to a violation of the integrity of the BBB) inside the brain (intracranial disorders), connective tissues with the spine, and in addition to this, lesions inside the sternum, pelvic cavity and retroperitoneal area.

At the same time, the drug improves the quality of visualization of neoplasms, as well as determining the severity of their invasiveness. The substance does not accumulate inside the brain that does not have pathological changes, as well as in lesions that do not have abnormal vascularization (for example, inside bones or old postoperative scars).

The drug does not lead to the potentiation of the signal of various types of disease processes - for example, certain types of highly differentiated neoplasms or inactive plaques that appear in multiple sclerosis.

Omniscan can be used to differentiate pathological and healthy tissues, various pathogenic structures, as well as to differentiate tumors or tumor relapses from scar tissues that appear after therapy.

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Pharmacokinetics

The drug undergoes rapid distribution within the extracellular fluid. The distribution volume is similar to the volume of fluids outside the cells.

The distribution half-life is approximately 4 minutes and the decay half-life is approximately 70 minutes.

In people with renal impairment, the half-life increases inversely proportional to the severity of the renal impairment. The drug can be removed from the body by hemodialysis.

Excretion occurs via the kidneys by glomerular filtration. In individuals with healthy renal function, approximately 85% of the substance is excreted unchanged in the urine 4 hours after administration of gadodiamide, and 95-98% after 24 hours.

When using doses of 0.1 and 0.3 mmol/kg, no portion-size-dependent changes in the pharmacokinetic parameters of the drug were recorded. The substance is not subject to metabolic processes and is not synthesized with proteins.

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Dosing and administration

The medicine is administered intravenously. The substance should be drawn into the syringe immediately before the procedure.

The substance is administered to an adult and a child using a bolus injection. To ensure the required completeness of the drug administration, it is necessary to flush the intravenous catheter with a 0.9% NaCl solution.

Contrast enhancement within the CNS.

Portion sizes for children and adults.

The recommended dosage portion size is 0.1 mmol/kg (or 0.2 ml/kg) if the weight is less than 100 kg. For people weighing more than 100 kg, 20 ml of the substance is often enough to provide adequate contrast for diagnostics.

If there is a suspicion of developing metastatic lesions inside the brain, the drug should be administered in 2 or 3 portions, up to 0.3 mmol/kg (or 0.6 ml/kg), for a weight of up to 100 kg. For people whose weight exceeds 100 kg, 60 ml is usually sufficient to obtain adequate contrast for diagnosis. A portion of 0.6 ml/kg can be administered by a single injection. In case of ambiguous study indications after potentiation of the contrast using 0.1 mmol/kg of the substance, a repeated bolus administration can be performed during the next 20 minutes - in a portion of 0.2 mmol/kg (or 0.4 ml/kg). This can help in obtaining additional diagnostic data.

Potentiation of contrast of internal organs and tissues.

Adults.

The recommended dose size is 0.1 mmol/kg (or 0.2 ml/kg), and if necessary, 0.3 mmol/kg (or 0.6 ml/kg), which is used for weights less than 100 kg. People weighing over 100 kg often require 20-60 ml of the substance to obtain optimal diagnostic contrast.

Children over 6 months of age.

It is necessary to administer 0.1 mmol/kg of substance (or 0.2 ml/kg).

Magnetic resonance imaging.

With contrast enhancement, MRI should be started a few minutes after the Omniscan injection, taking into account the pulse sequences that occur and the examination protocol. Tissue contrast is usually maintained for approximately 45 minutes after the injection. With contrast enhancement MRI, T1-weighted pulse sequences are the most optimal.

When administering drugs using a system with an automatic input type, a certificate from the equipment manufacturer is required that it is suitable for use with Omniscan. It is also necessary to strictly follow all operating instructions for the medical device.

People with renal insufficiency.

The drug is used only after preliminary risk-benefit assessment for people with moderate renal failure (glomerular filtration rate of 30-59 ml/minute/1.73 m²). Such patients can be administered a dose not exceeding 0.1 mmol/kg.

During the scan, only 1 dose is used. Since there is no data on repeated use of the drug, a new injection is allowed only after at least 7 days.

Use in newborns, infants and children.

Use in infants under 12 months of age is permitted only after a very careful examination. Such children are prescribed only a dosage of 0.1 mmol/kg. Only a single dose is used for scanning. A repeat injection can be prescribed at least 7 days after the first procedure, because there is no data on repeated use of the drug.

Contrast enhancement of internal tissues and organs is prohibited for children under six months of age.

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Use Omniscan during pregnancy

There is no information regarding the use of the drug during pregnancy. Animal tests have shown that reproductive toxicity develops in the case of repeated use of the drug in a large portion. It is not recommended to use Omniscan during pregnancy, unless there is a vital need for it.

There is no clinical information regarding excretion of the substance with breast milk in humans. Animal tests have shown that the drug is excreted with milk, so there is a risk to the breastfed infant. In this regard, before using the drug, it is necessary to stop breastfeeding - for at least the next 24 hours.

Contraindications

Main contraindications:

• the presence of severe sensitivity to the components of the drug;
• renal diseases that are severe and chronic (glomerular filtration rate is <30 ml/minute/1.73 m²);
• acute renal dysfunction;
• people who have recently had a liver transplant.

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Side effects Omniscan

The use of the drug can cause the appearance of various side effects:

• immune damage: sometimes symptoms of allergy on the epidermis and mucous membranes, as well as intolerance, appear. The development of anaphylactoid or anaphylactic manifestations is possible (this includes skin and respiratory reactions, as well as symptoms from the cardiovascular system)*;
• mental disorders: occasionally an anxious feeling arises;
• problems with the functioning of the nervous system: headaches are often observed. Sometimes paresthesia, dizziness and transient taste disorders occur. Rarely, tremors, convulsions and a feeling of drowsiness are observed, as well as transient olfactory impairment. Paresthesia, ataxia, paresis, development of a comatose state and coordination disorder are possible;
• visual disturbances: possible impairment of visual function;
• lesions affecting the function of the cardiovascular system: hyperemia sometimes appears. Tachycardia may develop;
• respiratory disorders: cough or dyspnea may occasionally occur. Bronchial spasms, throat irritation or sneezing may occur, as well as the development of RDS;
• problems with digestion: nausea often appears. Sometimes – diarrhea or vomiting. Belching may occur;
• liver dysfunction: problems with liver function may occur;
• subcutaneous and epidermal lesions: sometimes itching occurs. Rarely - urticaria, rashes, hyperhidrosis and swelling (facial and Quincke's edema). Development of NSF is possible;
• disorders in the functioning of connective tissues or the musculoskeletal system: myalgia or pain in the joints occasionally occurs;
• problems affecting renal function and urinary processes: occasionally, acute renal failure is observed, as well as an increase in blood creatinine levels;
• Systemic disorders and symptoms at the injection site: Often there is a transient feeling of pressure, cold or heat in the area of drug administration. Temporary pain in the injection areas may also occur. Rarely, fever, hot flashes, chest pain, manifestations at the injection site and tremors occur. A feeling of malaise or fatigue, as well as fainting, may develop.

*anaphylactoid or anaphylactic symptoms that develop regardless of the portion size or injection method may be an initial sign of the development of a shock state.

Delayed adverse effects may develop several hours or days after the drug has been used.

Transient asymptomatic changes in serum iron values have been observed in individual individuals.

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Overdose

Excess amounts of the substance are excreted by hemodialysis. However, there is no evidence that hemodialysis is used to prevent the development of NSF.

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Storage conditions

Omniscan must be kept in a place closed to small children and secondary X-ray radiation. The substance must not be frozen. Temperature indicators are within the range of 2-30°C.

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Shelf life

Omniscan can be used within 36 months from the date of manufacture of the medicinal substance.

The prepared solution retains its physical and chemical stability for another 8 hours at temperatures up to 25°C. However, from a microbiological point of view, it must be used immediately.

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Application for children

Omniscan can be used in pediatrics – for children and infants from 0.5 years old.

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Analogues

Analogues of the drug are the drugs Vazovist, Tomovist, Gadovist with Magnevist and Lantavist, and in addition Magnegita, Multihans, Magnilek and Optimark with Megarem.

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