ISOVUE-250
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ISOVUE-250 (ISOVUE-250).
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.
| Metabolism | 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. |
| Excretion | Primarily renal: 90-95% unchanged in urine within 24 hours; biliary/fecal: <5% |
| Half-life | Terminal elimination half-life: 1.5-2 hours (normal renal function); clinically, half-life prolonged in renal impairment |
| Protein binding | <5% bound; primarily to albumin |
| Volume of Distribution | 0.2-0.3 L/kg; reflects distribution in extracellular fluid (does not cross intact blood-brain barrier) |
| Bioavailability | Intravascular: 100%; oral: negligible (<1%) |
| Onset of Action | Intravascular injection: immediate (seconds to minutes); intrathecal: within minutes for contrast enhancement |
| Duration of Action | Intravascular: 15-30 minutes for contrast enhancement; intrathecal: 1-2 hours for adequate imaging |
Intravenous administration of 50-150 mL (12-37 g iodine) for CT imaging; intra-arterial administration of 10-80 mL (2.5-20 g iodine) for angiography; dose depends on procedure and patient weight.
| Dosage form | INJECTABLE |
| Renal impairment | eGFR <30 mL/min/1.73m²: avoid use or use minimal dose with adequate hydration; eGFR 30-59: consider lowest effective dose and ensure hydration; no specific dose reduction for eGFR ≥60. |
| Liver impairment | No specific Child-Pugh based dose modifications; use with caution in severe hepatic impairment due to potential contrast-induced nephropathy risk. |
| Pediatric use | Children: 1-2 mL/kg (250-500 mg iodine/kg) intravenously for CT, not to exceed adult dose; adjust for body weight and procedure. |
| Geriatric use | Elderly patients: use lowest effective dose; ensure adequate hydration; monitor renal function closely due to age-related decline and increased risk of nephropathy. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ISOVUE-250 (ISOVUE-250).
| Breastfeeding | 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. |
| Teratogenic Risk | 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. |
■ FDA Black Box Warning
Intrathecal administration may result in neurotoxicity including seizures, meningitis, and arachnoiditis. Inadvertent intravascular injection during intrathecal administration may cause serious adverse reactions.
| Serious Effects |
["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"]
| Precautions | ["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"] |
| Food/Dietary |
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| Fetal Monitoring | No specific maternal or fetal monitoring is required for ISOVUE-250 administration during pregnancy beyond standard assessment of maternal vital signs and observation for allergic reactions. If used near term, neonatal thyroid function tests (TSH and free T4) should be performed within the first week of life to rule out transient hypothyroidism. |
| Fertility Effects | No known adverse effects of iopamidol on fertility in humans have been reported. Animal studies have not shown impairment of fertility at clinically relevant doses. |
| 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. |
| Clinical Pearls | ISOVUE-250 (iopamidol 51%) is a nonionic, low-osmolality iodinated contrast medium used for angiography, urography, and CT enhancement. In patients with renal impairment (eGFR <30 mL/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. |
| Patient Advice | 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. |