PAMISCAN 370, 50 ML

Indications

• Computed tomography (CT) imaging
• Angiography
• Intravenous urography
• Myelography

Dosage

Children: Refer to the BNF for Children for appropriate dosing guidance in paediatric patients, as doses may vary based on age, weight, and specific imaging requirements.

Adults: The typical adult dose for iopamidol varies depending on the specific procedure and imaging requirements. For CT imaging, a common dose is 100-200 mL, administered intravenously. Refer to the BNF for specific dosing recommendations based on the procedure.

Mechanism of action

Iopamidol increases the contrast of vascular structures by absorbing X-rays, which allows for clearer imaging during radiological procedures. It may induce an elevation in serum potassium levels through the release of potassium into intravascular spaces, although studies indicate that the elevation caused by iopamidol is less significant compared to other contrast agents.

Pharmacodynamics

Iopamidol functions primarily as a contrast agent in diagnostic imaging, enhancing the clarity of images by increasing the attenuation of X-rays. Its pharmacodynamic properties include a low osmolality which reduces the risk of adverse reactions compared to high-osmolar contrast agents. The release of potassium may influence electrolyte balance, but the clinical significance of this is generally minimal.

Pharmacokinetics

Iopamidol is administered intravenously and is rapidly distributed in the vascular system. It is not significantly metabolized in the body and is primarily excreted unchanged by the kidneys. The elimination half-life in healthy individuals is approximately 2 hours, with renal clearance being the major route of elimination.

Adverse effects

• Nausea
• Vomiting
• Headache
• Dizziness
• Injection site reactions
• Hypotension
• Allergic reactions including anaphylaxis

Interactions

• Concurrent use with metformin may increase the risk of lactic acidosis in patients with renal impairment
• Other nephrotoxic agents may increase the risk of renal toxicity

Precautions

• Use with caution in patients with renal impairment
• Hydration is recommended to reduce the risk of renal complications
• Monitor serum creatinine levels in patients at risk for contrast-induced nephropathy

Pregnancy

Use only if clearly needed, as the risk to the fetus cannot be ruled out.

Breast-feeding

Iopamidol is excreted in breast milk, but the effects on the nursing infant are unknown. A decision should be made to discontinue breastfeeding or discontinue the drug.

Storage

Store at room temperature, away from light. Do not freeze.

Formulations

• Iopamidol 370 mg iodine/mL solution for injection
• Iopamidol 300 mg iodine/mL solution for injection

Mechanism of action

To test the hypothesis that iodinated contrast media may induce an elevation in serum potassium level, /contrast media was administered to rabbits and tested in-vitro according to four protocols./ Protocol A: After intravenous infusion of contrast media into six rabbits, alterations of potassium ion concentrations were measured. Protocol B: Fresh rabbit blood was mixed in vitro with contrast media, and the fluctuations in potassium were monitored over a 30-minute period. Protocol C: Similar to protocol B, except that blood from humans with no reaction to contrast media was used. For protocol A, blood potassium levels increased above baseline levels. The elevations were statistically significant (P < .05). For protocol B, diatrizoate and ioxaglate caused a gradual increase in blood potassium levels, but iopamidol did not. In protocol C, all three contrast media caused statistically significant elevation in potassium levels. The release of potassium was statistically significant at 5 minutes (P < .05 for diatrizoate and ioxaglate, and P < .01 for iopamidol). The mean release rates (+/- standard deviation) by means of linear regression analysis were 0.0190 mmol/min +/- 0.0112 with diatrizoate, 0.0159 mmol/min +/- 0.0057 with iopamidol, and 0.0088 mmol/min +/- 0.0033 with ioxaglate. Iodinated contrast media increase blood potassium levels causing release of potassium into intravascular spaces. This potassium release may play some role in contrast medium-induced adverse reactions. The synthesis of prostaglandins and other metabolic products of arachidonic acid (AA) was investigated in isolated perfused lungs of hamsters during the infusion of various concentrations of meglumine diatrizoate and iopamidol. Forty nmol of (14)C-AA was infused into the pulmonary circulation with radiographic contrast media (RCM), and prostaglandins, thromboxanes, and metabolites of lipoxygenases were analyzed from the nonrecirculating perfusion effluent. Arachidonate infusion increased the perfusion pressure. This pressor response was decreased by iopamidol ... The amount of radioactivity was decreased in the perfusion effluent and increased in lung lipids by iopamidol. ... Almost all arachidonate metabolites were decreased significantly by iopamidol when compared with hypertonic saline ...