OMNIPAQUE (iohexol)

OMNIPAQUE (iohexol)

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OMNIPAQUE (iohexol)

OMNIPAQUE (iohexol) injection is a nonionic, x-ray or radiographic contrast medium for intrathecal, intravenous, oral, rectal and body cavity use. OMNIPAQUE oral solution is for oral use only.

OMNIPAQUE injection and OMNIPAQUE oral solution are both provided as sterile, pyrogen-free and gluten-free solutions. OMNIPAQUE injection and OMNIPAQUE oral solution are colorless to pale yellow solutions. The chemical name of iohexol is Bis(2,3-dihydroxypropyl)-5-[N-(2,3-dihydroxypropyl)-acetamido]-2,4,6- triiodoisophthalamide with a molecular weight of 821.14 (iodine content 46.36%).

Mechanism of Action

The iodine atoms in iohexol provide attenuation of X-rays in direct proportion to the concentration of iohexol. Since concentration changes over time, iohexol provides time-dependent image contrast which may assist in visualizing body structures.

Indications and usage

Intrathecal Administration

Adults: OMNIPAQUE 180, 240, and 300

  • Myelography (lumbar, thoracic, cervical, total columnar)
  • Computerized Tomography (CT) (myelography, cisternography, ventriculography)

Pediatrics: OMNIPAQUE 180

  • Myelography (lumbar, thoracic, cervical, total columnar)
  • CT (myelography, cisternography)

Intravascular Administration

Adults: OMNIPAQUE 140

  • Intra-arterial digital subtraction angiography of the head, neck, abdominal, renal and peripheral vessels

OMNIPAQUE 240

  • CT head imaging
  • Peripheral venography (phlebography)

OMNIPAQUE 300

  • Aortography including studies of the aortic arch, abdominal aorta and its branches
  • CT head and body imaging
  • Cerebral arteriography
  • Peripheral venography (phlebography)
  • Peripheral arteriography
  • Excretory urography

OMNIPAQUE 350

  • Angiocardiography (ventriculography, selective coronary arteriography)
  • Aortography including studies of the aortic root, aortic arch, ascending aorta, abdominal aorta and its branches
  • CT head and body imaging
  • Intravenous digital subtraction angiography of the head, neck, abdominal, renal and peripheral vessels
  • Peripheral arteriography
  • Excretory urography

Pediatrics: OMNIPAQUE 240

  • CT head and body imaging

OMNIPAQUE 300

  • Angiocardiography (ventriculography)
  • Excretory urography
  • CT head and body imaging

OMNIPAQUE 350

  • Angiocardiography (ventriculography, pulmonary arteriography, venography, and studies of the collateral arteries)
  • Aortography including the aortic root, aortic arch, ascending and descending aorta

Oral or Rectal Administration

Adults: OMNIPAQUE 350

  • Oral radiographic examination of the gastrointestinal tract

Pediatrics: OMNIPAQUE 180, 240 and 300

  • Oral and rectal radiographic examination of the gastrointestinal tract

Oral Administration in Conjunction with Intravenous Administration

Diluted OMNIPAQUE Injection

Adults: OMNIPAQUE 240, 300 and 350 diluted and administered orally in conjunction with OMNIPAQUE 300 administered intravenously

  • CT of the abdomen

Pediatrics: OMNIPAQUE 240, 300 and 350 diluted and administered orally in conjunction with OMNIPAQUE 240 or OMNIPAQUE 300 administered intravenously

  • CT of the abdomen

OMNIPAQUE Oral Solution

Adults: OMNIPAQUE oral solution 9 and 12 administered orally in conjunction with OMNIPAQUE 300 administered intravenously

  • CT of the abdomen

Pediatrics: OMNIPAQUE oral solution 9 and 12 administered orally in conjunction with OMNIPAQUE 240 or OMNIPAQUE 300 administered intravenously

  • CT of the abdomen

Intraarticular Administration

Adults: OMNIPAQUE 240, 300, and 350

  • Arthrography

Pharmacokinetics

Following the intravenous administration of iohexol (between 500 mg iodine/kg to 1500 mg iodine/kg) to 16 adult human subjects, apparent first-order terminal elimination half-life was 12.6 hrs and total body clearance was 131 (98-165) mL/min. Clearance was not dose dependent.

Absorption: As evidenced by the amount recovered in urine, <1% of orally administered iohexol is absorbed from the normal gastrointestinal tract. This amount may increase in the presence of bowel perforation or bowel obstruction.

Distribution: In 16 adult subjects (receiving between 500 mg iodine/kg to 1500 mg iodine/kg intravenous iohexol) the plasma volume of distribution was165 (108-219) mL/kg.

In five adult patients receiving 16 mL to 18 mL of OMNIPAQUE (180 mg iodine/mL) by lumbar intrathecal injection the plasma volume of distribution was 559 (350-849) mL/kg.

Elimination

Metabolism: No significant metabolism, deiodination or biotransformation occurs.

Excretion: Following intravascular or intrathecal administration, iohexol is excreted unchanged by glomerular filtration. Approximately 90% of the intravenously injected iohexol dose is excreted within the first 24 hours. Following intravascular administration, peak urine concentration occurs in the first hour after injection.

Dosage and administration

The concentration and volume required will depend on the indication, size and condition of the patient, and the equipment and imaging technique used. For CT of the head and body, OMNIPAQUE may be used with an automated contrast injection system or contrast media management system cleared for use with OMNIPAQUE.

Contraindications

  • OMNIPAQUE 140 and OMNIPAQUE 350 are contraindicated for intrathecal use
  • OMNIPAQUE oral solution 9 and 12 are contraindicated for parenteral administration
  • OMNIPAQUE body cavity 240 and 300 for hysterosalpingography is contraindicated during pregnancy or suspected pregnancy, menstruation or when menstruation is imminent, within 6 months after termination of pregnancy, within 30 days after conization or curettage, when signs of infection are present in any portion of the genital tract including the external genitalia, and when reproductive tract neoplasia is known or suspected because of the risk of peritoneal spread of neoplasm.

Adverse effects

Intrathecal: Headaches, Pain including backache, neckache, stiffness and neuralgia, nausea, vomiting and dizziness

Intravascular: Pain, vision abnormalities (including blurred vision and photomas), headache, taste perversion, arrhythmias including premature ventricular contractions (PVCs) and premature atrial contractions (PACs), angina/chest pain, nausea

Oral: Diarrhea, nausea, vomiting, abdominal pain, flatulence, headache

Body Cavity: Pain, swelling and heat sensation

Warnings and precautions

  • Hypersensitivity Reactions: Life-threatening or fatal reactions can occur. Always have emergency equipment and trained personnel available.
  • Contrast Induced Acute Kidney Injury: Acute injury including renal failure can occur. Minimize dose and maintain adequate hydration to minimize risk.
  • Cardiovascular Reactions: Hemodynamic disturbances including shock and cardiac arrest may occur during or after administration

Drug Laboratory Test Interactions

Effect on Thyroid Tests: If iodine-containing isotopes are to be administered for the diagnosis of thyroid disease, the iodine-binding capacity of thyroid tissue may be reduced for up to 2 weeks after contrast medium administration. Thyroid function tests that do not depend on iodine estimation, e.g., T3 resin uptake or direct thyroxine assays, are not affected.

Use in specific populations

Pregnancy: Hysterosalpingography is contraindicated in pregnant women due to the potential risk to the fetus from an intrauterine procedure. There are no data with iohexol use in pregnant women to inform any drug-associated risks. Iohexol crosses the placenta and reaches fetal tissues in small amounts. In animal reproduction studies, no developmental toxicity occurred with intravenous iohexol administration to rats and rabbits at doses up to 0.4 (rat) and 0.5 (rabbit) times the maximum recommended human intravenous dose.

Lactation: Published literature reports that breast feeding after intravenous iohexol administration to the mother would result in the infant receiving an oral dose of approximately 0.7% of the maternal intravenous dose; however, lactation studies have not been conducted with oral, intrathecal, or intracavity administration of iohexol. There is no information on the effects of the drug on the breastfed infant or on milk production. Iodinated contrast agents are excreted unchanged in human milk in very low amounts with poor absorption from the gastrointestinal tract of a breastfed infant. Exposure to iohexol to a breastfed infant can be minimized by temporary discontinuation of breastfeeding (see Clinical Considerations). The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for OMNIPAQUE and any potential adverse effects on the breastfed infant from OMNIPAQUE or from the underlying maternal condition.

Interruption of breastfeeding after exposure to iodinated contrast agents is not necessary because the potential exposure of the breastfed infant to iodine is small. However, a lactating woman may consider interrupting breastfeeding and pumping and discarding breast milk for 10 hours (approximately 5 elimination half-lives) after OMNIPAQUE administration to minimize drug exposure to a breastfed infant.

Geriatric Use: In clinical studies of OMNIPAQUE for CT, 52/299 (17%) of patients were 70 and over. No overall differences in safety were observed between these patients and younger patients. Other reported clinical experience has not identified differences in response between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. In general, dose selection for an elderly patient should be cautious usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

Overdosage

The adverse effects of overdosage are life-threatening and affect mainly the pulmonary and cardiovascular systems. The symptoms included: cyanosis, bradycardia, acidosis, pulmonary hemorrhage, convulsions, coma, and cardiac arrest. Treatment of an overdosage is directed toward the support of all vital functions, and prompt institution of symptomatic therapy. Iohexol displays a low affinity for serum or plasma proteins and is poorly bound to serum albumin and can be dialyzed.

Storage and Handling

Protect OMNIPAQUE glass vials and bottles and +PLUSPAK™ polymer bottles from light. Do not freeze. Discard any product that is inadvertently frozen, as freezing may compromise the closure integrity of the immediate container.

OMNIPAQUE Injection 140, 180, 240, 300 and 350: Store at controlled room temperature, 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. May be stored in a contrast media warmer for up to one month at 36° to 38°C (96.8° to 100.4°F).

OMNIPAQUE Oral Solution 9 and 12: Store between 0° and 30°C (32° to 86°F).

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