1. Clinical Overview
Iopromide is a non-ionic, low-osmolar, monomeric iodinated contrast medium used for intravascular and intrathecal radiographic imaging. It contains 300 mg of organically bound iodine per milliliter. Its low osmolality (approximately 590 mOsm/kg water at 37°C for the 300 mg I/ml concentration) reduces the risk of adverse hemodynamic and pain reactions compared to older ionic agents. It is widely used in computed tomography (CT), angiography, and urography in the Indian healthcare setting.
| Onset | Duration | Bioavailability |
|---|---|---|
| Immediate upon intravascular injection; peak opacification occurs within seconds to minutes depending on the imaging procedure. | Contrast effect typically lasts for the duration of the imaging procedure (minutes). Pharmacological effects are transient. | 100% upon intravascular administration. Not applicable for oral bioavailability as it is not absorbed via the GI tract for diagnostic purposes. |
2. Mechanism of Action
Iopromide is a radiopaque contrast agent. It contains iodine atoms (which have a high atomic number) that effectively absorb X-rays. When injected into blood vessels, body cavities, or the subarachnoid space, it attenuates X-rays passing through the body, creating a contrast between the fluid-filled spaces (e.g., blood vessels, renal collecting system, cerebrospinal fluid) and surrounding tissues on radiographic images.
3. Indications & Uses
- Computed Tomography (CT) of the body (head, thorax, abdomen, pelvis) for enhancement of vascular structures and parenchymal organs
- Digital Subtraction Angiography (DSA) of peripheral, cerebral, coronary, and visceral arteries
- Excretory Urography (IVU) for visualization of the kidneys, ureters, and bladder
- Contrast-enhanced CT Angiography (CTA)
4. Dosage & Administration
Adult Dosage: Dose depends on type of examination, patient weight, and imaging equipment. General IV guidelines: CT Body: 50-150 ml (15-45 g I); Angiography: Varies by vessel (e.g., cerebral: 5-10 ml per injection, aortic: 20-50 ml). Maximum single dose should not exceed the lowest dose necessary for adequate imaging.
Administration: For intravascular use: Administer as a bolus injection or controlled infusion using a power injector. Use strict aseptic technique. Pre-warming to body temperature reduces viscosity. For intrathecal use (myelography): MUST use only the specific formulation approved for intrathecal administration. Administer via lumbar puncture after dilution with CSF. Patient must remain in semi-upright position. Do not mix with other drugs or solutions.
5. Side Effects
Common side effects may include:
- Sensation of warmth/flushing (most common)
- Metallic taste in mouth
- Nausea
- Mild pain at injection site
- Headache (especially post-myelography)
- Vomiting
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Metformin | Risk of lactic acidosis if contrast-induced nephropathy occurs. Must be withheld before and after procedure as per protocol. | High |
| Interleukin-2 | Increased risk of delayed hypersensitivity reactions to contrast media. | Moderate |
| Beta-blockers | May mask tachycardia as an early sign of anaphylaxis and may impair response to epinephrine. | Moderate |
| NSAIDs (e.g., Ibuprofen) | May increase risk of contrast-induced nephropathy, especially in pre-existing renal impairment. | Moderate |
| Diuretics (e.g., Furosemide) | May potentiate dehydration and increase risk of nephrotoxicity. | Moderate |
| Other Nephrotoxic drugs (Aminoglycosides, Amphotericin B) | Additive risk of acute kidney injury. | High |
7. Patient Counselling
- DO inform your doctor about all allergies, especially to iodine, shellfish, or previous contrast reactions.
- DO inform your doctor about all medications, including over-the-counter drugs and herbal supplements.
- DO inform your doctor if you are pregnant, planning pregnancy, or breastfeeding.
- DO follow pre-procedure instructions regarding fasting or medication adjustments (e.g., metformin).
- DO drink plenty of fluids after the procedure unless instructed otherwise, to help flush the contrast from your kidneys.
- DONT hesitate to report any unusual sensations like itching, rash, shortness of breath, or swelling during or after the procedure.
8. Toxicology & Storage
Overdose: Symptoms are extensions of its pharmacological and adverse effects: Severe circulatory disturbances (shock, pulmonary edema, cardiac arrest), renal failure, seizures (with intrathecal overdose), and severe neurological complications.
Storage: Store below 30°C. Do not freeze. Protect from light. Keep the container in the outer carton. The solution should be visually inspected for particulate matter and discoloration before use. Discard any unused portion. Do not mix with other medications.