Omnipaque (Iohexol)

Omnipaque is an iodinated contrast agent used in radiographic procedures that require enhanced visualization of vascular and tissue structures.

• Cerebral angiography: improves imaging of cerebral vessels and detects aneurysms or malformations.
• CT urography: provides detailed images of the urinary tract for stone detection and tumor assessment.
• Cardiac catheterisation: enhances visualization of coronary arteries and cardiac chambers during interventional procedures.
• Peripheral angiography: delineates limb vessels to assess occlusions or stenoses.
• Myelography: improves contrast of the spinal canal and nerve roots for diagnostic evaluation.
• Abdominal CT: offers enhanced delineation of abdominal organs and vascular anatomy.

• Iohexol is a water‑soluble, non‑ionic iodinated compound that, when injected intravascularly, distributes rapidly throughout the extracellular fluid and absorbs X‑rays. Its high atomic number iodine atoms increase radiodensity, creating a temporary contrast between blood‑filled structures and surrounding tissues, thereby allowing detailed imaging of vascular and organ anatomy during diagnostic procedures.

Adverse reactions to Omnipaque may range from mild to severe and are typically related to its iodine content and osmolar properties.

Common Side Effects

• Warmth or flushing sensation at the injection site.
• Mild nausea or vomiting.
• Transient headache.
• Mild itching or skin rash.
• Temporary metallic taste.
• Slight increase in serum creatinine (often reversible).

Serious or Rare Side Effects

• Severe allergic reaction (anaphylaxis).
• Acute kidney injury, especially in patients with pre‑existing renal impairment.
• Hypotension or cardiovascular collapse.
• Pulmonary edema.
• Seizures.
• Persistent severe pain at the injection site.

When using Omnipaque, clinicians should assess patient risk factors and follow recommended safety measures.

• Renal function assessment: evaluate baseline creatinine and eGFR before administration.
• Allergy history: screen for prior reactions to iodinated contrast or other allergens.
• Hydration status: ensure adequate patient hydration to reduce nephrotoxic risk.
• Thyroid disease: monitor thyroid function in patients with known disorders.
• Concurrent nephrotoxic drugs: consider dose adjustment or alternative imaging if possible.
• Store at ambient temperature: keep in original packaging, protect from light and moisture.

Omnipaque may interact with other agents that affect renal function or hypersensitivity risk.

Major Interactions (Avoid)

• Nephrotoxic antibiotics (e.g., aminoglycosides): combined use can increase risk of acute kidney injury.
• High‑dose NSAIDs: may potentiate renal impairment when given with contrast.

Moderate Interactions (Monitor Closely)

• Metformin: risk of lactic acidosis if renal function declines after contrast exposure; hold metformin as advised.
• Diuretics: may affect fluid balance and renal clearance of contrast.
• Beta‑blockers: can mask early signs of contrast‑induced hypertension.
• ACE inhibitors/ARBs: monitor blood pressure and renal function closely.
• Thyroid hormones: contrast iodine may transiently affect thyroid hormone levels.