OMNIPAQUE 300
Clinical safety rating: caution
Comprehensive clinical and safety monograph for OMNIPAQUE 300 (OMNIPAQUE 300).
Iodinated contrast agent that attenuates X-rays, providing vascular and tissue opacification by increasing the density of blood vessels and organs.
| Metabolism | Not metabolized; excreted unchanged by glomerular filtration. |
| Excretion | Omnipaque 300 (iohexol) is primarily eliminated unchanged by the kidneys via glomerular filtration. Renal excretion accounts for >95% of the administered dose within 24 hours in patients with normal renal function. Fecal excretion is negligible (<1%). Billiary excretion is minimal, with less than 0.1% recovered in bile or feces. |
| Half-life | The terminal elimination half-life of iohexol in patients with normal renal function (creatinine clearance > 90 mL/min) is approximately 1.5 to 2 hours. In patients with renal impairment, the half-life is significantly prolonged (up to 30 hours or more in severe renal failure), necessitating dose adjustment and careful monitoring. |
| Protein binding | Protein binding of iohexol is minimal (<1%). It does not bind significantly to plasma proteins such as albumin, which contributes to its high renal clearance and distribution primarily in extracellular fluid. |
| Volume of Distribution | The volume of distribution (Vd) of iohexol is approximately 0.16 to 0.27 L/kg (mean about 0.20 L/kg), consistent with distribution primarily in the extracellular fluid compartment. It does not significantly enter cells or cross the blood-brain barrier in the absence of pathology (except when administered intrathecally). |
| Bioavailability | Omnipaque is administered intravenously, intra-arterially, intrathecally, or into body cavities; oral and rectal administration are also used for gastrointestinal studies. The bioavailability is 100% after intravascular administration. After oral or rectal administration, systemic absorption is minimal (<1% for oral), as iohexol is not significantly absorbed from the gastrointestinal tract; systemic bioavailability is negligible, limiting systemic effects. |
| Onset of Action | Following intravenous administration, opacification of the vascular system occurs immediately (within seconds to minutes). For intrathecal administration (myelography), radiographic opacification is typically seen within 10 to 30 minutes. For oral or rectal routes (gastrointestinal studies), opacification occurs within 15 to 60 minutes, depending on transit time. |
| Duration of Action | For intravenous administration, diagnostic contrast enhancement persists for 15 to 30 minutes, sufficient for most imaging procedures. For intrathecal administration, myelographic opacification lasts approximately 30 to 60 minutes, with cerebrospinal fluid levels declining over hours. For oral or rectal routes, gastrointestinal opacification may persist for 30 to 90 minutes, depending on motility. The duration is sufficient for the planned diagnostic procedure but may be limited in patients with rapid transit. |
Intravenous: 1-2 mL/kg (300 mg I/mL) for contrast-enhanced CT; intra-arterial: 5-80 mL per injection depending on procedure; maximum total dose 4 mL/kg.
| Dosage form | SOLUTION |
| Renal impairment | eGFR 30-59 mL/min: reduce dose by 50% and ensure adequate hydration; eGFR <30 mL/min: avoid use; consider alternative imaging or lowest possible dose with hemodialysis. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: use with caution, reduce dose by 25%; Child-Pugh C: avoid use due to risk of hepatic encephalopathy. |
| Pediatric use | Intravenous: 2 mL/kg (300 mg I/mL) total not exceeding 4 mL/kg; intra-arterial: 1-2 mL/kg per injection adjusted for patient size. |
| Geriatric use | Reduce dose by 25-50% due to age-related decline in renal function; ensure adequate hydration; monitor renal function pre- and post-procedure. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for OMNIPAQUE 300 (OMNIPAQUE 300).
| Breastfeeding | Very small amounts of iodinated contrast media are excreted into breast milk (less than 1% of maternal dose). M/P ratio not reported; average contrast load excreted in milk over 24h is <0.1% of maternal dose. Negligible absorption from infant gastrointestinal tract due to low bioavailability. Consider pumping and discarding breast milk for 24 hours after administration to minimize any potential risk, though this is not mandatory. |
| Teratogenic Risk | No adequate and well-controlled studies in pregnant women. Iodinated contrast media cross the placenta and can cause fetal thyroid suppression (hypothyroidism) when administered after the first trimester. Risk of fetal hypothyroidism is dose- and duration-dependent. Inadvertent exposure during first trimester is not associated with major congenital malformations based on limited human data. Use only if clearly needed, with consideration of alternative imaging modalities. |
■ FDA Black Box Warning
Risk of contrast-induced nephropathy in patients with preexisting renal impairment, diabetes, or dehydration. Use with caution and ensure adequate hydration.
| Serious Effects |
["Hypersensitivity to iohexol or any component","Anuria","Severe oliguria","Concurrent administration of metformin in patients with renal impairment"]
| Precautions | ["Contrast-induced acute kidney injury","Anaphylactoid reactions","Thyroid storm in patients with hyperthyroidism","Severe cutaneous adverse reactions","Interference with thyroid function tests"] |
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| Fetal Monitoring | Monitor for acute hypersensitivity reactions (urticaria, bronchospasm, anaphylaxis) and contrast-induced nephropathy (serum creatinine, urine output). Fetal monitoring appropriate for gestational age after contrast exposure, particularly assessment for neonatal thyroid function (TSH, free T4) following second or third trimester exposure. |
| Fertility Effects | No data on human fertility effects from omnipaque 300. Animal studies show no impairment of fertility at clinically relevant doses. No known adverse effects on spermatogenesis or ovarian function. Theoretical risk of gonadal radiation exposure if used in fluoroscopic procedures should be considered. |