Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ISOVUE-250 vs ISOVUE-370
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Iopamidol is a nonionic, water-soluble iodinated radiographic contrast agent that attenuates X-rays, thereby providing contrast enhancement in imaging studies. Its mechanism of action is physical rather than pharmacological, as it does not have inherent biological activity.
Iodinated contrast agent that attenuates X-rays, providing radiographic contrast by increasing the density of vascular structures and tissues.
Intravascular use for computed tomography (CT) of the head and body,Intrathecal use for lumbar, thoracic, and cervical myelography,Coronary arteriography and ventriculography,Peripheral arteriography,Excretory urography,Visceral angiography
Intravascular administration for computed tomography (CT) imaging,Intrathecal administration for myelography (CT and conventional),Angiography (coronary, cerebral, peripheral, etc.),Intravenous urography,Left ventriculography,Arteriography,Other radiographic contrast procedures
Intravenous administration of 50-150 m L (12-37 g iodine) for CT imaging; intra-arterial administration of 10-80 m L (2.5-20 g iodine) for angiography; dose depends on procedure and patient weight.
Intravenous injection of 50-200 m L of Isovue-370 (iopamidol 76% solution, 370 mg I/m L) for adults, administered as a bolus or infusion depending on imaging protocol. Typical dose for CT: 100-150 m L total volume.
Terminal elimination half-life: 1.5-2 hours (normal renal function); clinically, half-life prolonged in renal impairment
Terminal elimination half-life is approximately 1.5-2 hours in patients with normal renal function (creatinine clearance >60 m L/min); prolonged to up to 30 hours in severe renal impairment.
Iopamidol is not metabolized. It is excreted unchanged by glomerular filtration, primarily via the kidneys. In patients with normal renal function, 90% or more of the administered dose is eliminated in the urine within 24 hours.
Not metabolized; eliminated unchanged via glomerular filtration.
Primarily renal: 90-95% unchanged in urine within 24 hours; biliary/fecal: <5%
Primarily renal (glomerular filtration) with >95% of administered dose excreted unchanged in urine within 24 hours. Less than 1% excreted in feces.
<5% bound; primarily to albumin
Minimal; approximately 1-5% bound to serum proteins (primarily albumin).
0.2-0.3 L/kg; reflects distribution in extracellular fluid (does not cross intact blood-brain barrier)
Volume of distribution (Vd) is approximately 0.2-0.3 L/kg, reflecting distribution primarily in extracellular fluid (plasma and interstitial space).
Intravascular: 100%; oral: negligible (<1%)
Not applicable (administered intravascularly); bioavailability is 100% for intravenous and intra-arterial routes as it does not undergo first-pass metabolism.
e GFR <30 m L/min/1.73m²: avoid use or use minimal dose with adequate hydration; e GFR 30-59: consider lowest effective dose and ensure hydration; no specific dose reduction for e GFR ≥60.
No specific dose adjustment guidelines exist for Isovue-370 in renal impairment; however, caution is advised. In patients with GFR < 30 m L/min/1.73m², use lowest necessary dose and ensure adequate hydration. Hemodialysis may remove contrast; post-procedure dialysis can be considered.
No specific Child-Pugh based dose modifications; use with caution in severe hepatic impairment due to potential contrast-induced nephropathy risk.
No specific dose adjustment is required based on hepatic impairment; monitor renal function closely in patients with severe hepatic disease due to potential reduced clearance.
Children: 1-2 m L/kg (250-500 mg iodine/kg) intravenously for CT, not to exceed adult dose; adjust for body weight and procedure.
Weight-based dosing: 1-2 m L/kg (3.7-7.4 mg I/kg) intravenously, not exceeding 3 m L/kg total dose. Adjusted based on imaging indication and patient factors; for CT, 1.5-2 m L/kg typical.
Elderly patients: use lowest effective dose; ensure adequate hydration; monitor renal function closely due to age-related decline and increased risk of nephropathy.
Elderly patients may require lower doses due to age-related renal impairment and increased risk of contrast-induced nephropathy. Use the minimal effective dose and ensure adequate hydration. Individualize based on renal function.
Intrathecal administration may result in neurotoxicity including seizures, meningitis, and arachnoiditis. Inadvertent intravascular injection during intrathecal administration may cause serious adverse reactions.
No FDA black box warning.
Do not use for myelography if procedures are contraindicated,Risk of serious adverse reactions in patients with impaired renal function, including acute renal failure,Risk of cardiorespiratory arrest, anaphylactic shock, and other severe allergic reactions,Potential for thyroid storm in patients with hyperthyroidism,Caution in patients with pheochromocytoma, sickle cell disease, and multiple myeloma
Risk of serious anaphylactic reactions; have emergency equipment available.,Acute renal toxicity, especially in patients with pre-existing renal impairment, diabetes, or dehydration.,Contrast-induced nephropathy; ensure adequate hydration.,Extravasation risk; monitor injection site.,Thyroid storm in patients with hyperthyroidism or thyroid nodules.,Severe cutaneous adverse reactions (e.g., Stevens-Johnson syndrome).,Exacerbation of sickle cell disease.,Intrathecal use may cause neurotoxicity; avoid high doses.
History of severe allergic reaction to iopamidol or any component of the formulation,Intrathecal administration in patients with thrombophlebitis, infection, or malignancy at the injection site,Severe renal impairment (anuria, oliguria) unless the benefits outweigh the risks,Patients with a history of grand mal seizures, or those on drugs that lower seizure threshold, for intrathecal use
History of hypersensitivity to iopamidol or other iodinated contrast agents.,Acute pancreatitis (for intrathecal use).,Intrathecal administration in patients with blood in CSF or increased intracranial pressure.,Anuria or severe renal impairment (relative).
No known food interactions. However, ensure adequate hydration before and after the procedure. Avoid alcohol 24 hours prior as it may increase risk of dehydration.
No specific food restrictions are required for this contrast agent. Maintain adequate hydration before and after administration. No known food-drug interactions.
ISOVUE-250 (iopamidol) is an iodinated contrast agent. In pregnant women, exposure to ionizing radiation from procedures involving iodinated contrast should be minimized. Iodinated contrast agents cross the placenta and may produce transient neonatal hypothyroidism if used in the third trimester. However, data from clinical studies are insufficient to determine a definitive teratogenic risk. First trimester exposure has not been associated with major congenital malformations, but caution is warranted due to potential fetal hypothyroidism with prolonged use near term.
Iodinated contrast media, including iopamidol (ISOVUE-370), cross the placenta. In animal studies, no teratogenic effects were observed at clinically relevant doses. However, due to potential fetal hypothyroidism from free iodide exposure, use in pregnancy only if clearly needed. First trimester: theoretical risk of fetal thyroid suppression; second and third trimesters: risk of neonatal hypothyroidism if high doses or repeated exposures. No documented congenital malformations in human data.
Limited data suggest that iopamidol is excreted into human breast milk in very small amounts. The milk-to-plasma (M/P) ratio is not specifically reported for iopamidol, but for similar iodinated contrast agents, the M/P ratio is low (<0.2). The amount of iodine transferred to the infant is negligible and unlikely to cause adverse effects. However, the American College of Radiology and other guidelines recommend that breastfeeding may be continued without interruption after receiving iodinated contrast, although some advise discarding milk for 12-24 hours if the mother is concerned.
Iopamidol is excreted into human breast milk in minimal amounts (estimated infant dose <0.01% of maternal dose). M/P ratio not available. Because of low oral bioavailability and rapid milk clearance, breastfeeding can be continued without interruption; some sources suggest discarding milk for 12-24 hours post-procedure as a precaution.
Pregnancy does not require dose adjustments for ISOVUE-250. The dose should be based on the diagnostic procedure and patient weight. However, because of potential fetal hypothyroidism risk from free iodide, alternative imaging modalities without iodinated contrast should be considered if possible, especially in the third trimester.
No specific dose adjustment required for pregnancy based on pharmacokinetic changes. However, because of increased plasma volume and glomerular filtration rate in pregnancy, the elimination half-life may be slightly reduced. Use the lowest effective dose to minimize fetal iodide exposure. Adequate hydration is essential to prevent contrast-induced nephropathy.
ISOVUE-250 (iopamidol 51%) is a nonionic, low-osmolality iodinated contrast medium used for angiography, urography, and CT enhancement. In patients with renal impairment (e GFR <30 m L/min), consider N-acetylcysteine prophylaxis and hydration to reduce risk of contrast-induced nephropathy. Monitor for delayed hypersensitivity reactions, which can occur up to 7 days post-administration. Use caution in patients with pheochromocytoma; pre-treat with alpha-blockers. Shellfish allergy is not a contraindication; true iodine allergy is rare. For intrathecal use, avoid concurrent neurotoxic drugs and ensure patient hydration.
Pre-warm contrast to body temperature to reduce viscosity and patient discomfort. Assess renal function (e GFR >30 m L/min/1.73m²) prior to administration; use lowest possible dose in patients with renal impairment. Have emergency equipment available for hypersensitivity reactions. For intravascular use, ensure adequate hydration before and after procedure. In diabetic patients taking metformin, withhold metformin for 48 hours post-contrast and monitor renal function.
Inform your doctor if you have kidney disease, diabetes, or are taking metformin; metformin may need to be stopped temporarily.,Tell your doctor about all allergies, especially to medications or iodine.,You may feel warmth, flushing, or a metallic taste when the contrast is injected; this is normal.,Drink plenty of water before and after the procedure to help flush the contrast from your body.,Report any symptoms like hives, itching, difficulty breathing, or swelling of the face/mouth immediately.,If you are pregnant or breastfeeding, discuss potential risks with your doctor.
Inform your doctor if you have a history of allergic reactions to contrast media, asthma, or allergies.,Drink plenty of fluids before and after the procedure to help protect your kidneys.,Report any symptoms such as hives, itching, difficulty breathing, or swelling of the face/throat immediately.,If you are diabetic and take metformin, ask your doctor about temporarily stopping it.,You may feel warmth or a metallic taste during injection; these sensations are temporary.,Notify your doctor if you are pregnant, nursing, or have kidney disease.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ISOVUE-250 vs ISOVUE-370, answered by our medical review team.
ISOVUE-250 is a Contrast Media that works by Iopamidol is a nonionic, water-soluble iodinated radiographic contrast agent that attenuates X-rays, thereby providing contrast enhancement in imaging studies. Its mechanism of action is physical rather than pharmacological, as it does not have inherent biological activity.. ISOVUE-370 is a Contrast Media that works by Iodinated contrast agent that attenuates X-rays, providing radiographic contrast by increasing the density of vascular structures and tissues.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ISOVUE-250 and ISOVUE-370 depend on the specific clinical indication. These are both Contrast Media agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ISOVUE-250 is: Intravenous administration of 50-150 m L (12-37 g iodine) for CT imaging; intra-arterial administration of 10-80 m L (2.5-20 g iodine) for angiography; dose depends on procedure and patient weight.. The standard adult dose of ISOVUE-370 is: Intravenous injection of 50-200 m L of Isovue-370 (iopamidol 76% solution, 370 mg I/m L) for adults, administered as a bolus or infusion depending on imaging protocol. Typical dose for CT: 100-150 m L total volume.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ISOVUE-250 and ISOVUE-370 in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ISOVUE-250 is classified as Category C. ISOVUE-250 (iopamidol) is an iodinated contrast agent. In pregnant women, exposure to ionizing radiation from procedures involving iodinated contrast should be minimized. Iodinated. ISOVUE-370 is classified as Category C. Iodinated contrast media, including iopamidol (ISOVUE-370), cross the placenta. In animal studies, no teratogenic effects were observed at clinically relevant doses. However, due t. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.