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Omnipaque 240 Side Effects

Generic Name: iohexol

Note: This document contains side effect information about iohexol. Some of the dosage forms listed on this page may not apply to the brand name Omnipaque 240.

For the Consumer

Applies to iohexol: oral powder for solution

Along with its needed effects, iohexol (the active ingredient contained in Omnipaque 240) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking iohexol:

Incidence not known

  • Diarrhea
  • fever
  • joint or muscle pain
  • nausea
  • numbness or tingling of the face, hands, or feet
  • redness and soreness of the eyes
  • skin rash
  • sores in the mouth
  • stomach pain
  • swelling of the feet or lower legs
  • vomiting

For Healthcare Professionals

Applies to iohexol: injectable solution


The most frequently reported adverse reactions are headache, mild to moderate pain including backache, neckache and stiffness, nausea, and vomiting. These reactions usually occur 1 to 10 hours after injection, and almost all occur within 24 hours. They are usually mild to moderate in degree, lasting for a few hours, and usually disappearing within 24 hours.[Ref]


Very common (10% or more): Diarrhea (oral/body cavity routes)
Common (1% to 10%): Nausea, vomiting, pancreatitis (endoscopic retrograde cholangiopancreatography), lower abdominal pain (hysterosalpingography)
Uncommon (0.1% to 1%): Abdominal pain, stomach ache
Rare (0.01% to 0.1%): Diarrhea
Very rare (less than 0.01%): Tenderness and/or enlargement of the salivary glands ("iodide mumps"), abdominal discomfort
Frequency not reported: Aggravation of pancreatitis, acute pancreatitis[Ref]

Nervous system

Rarely, headaches may be severe or persist for days. Headache is often accompanied by nausea and vomiting and tends to be more frequent and persistent in patients not optimally hydrated.
Aseptic meningitis syndrome was usually preceded by pronounced headaches, nausea and vomiting. Onset usually occurred about 12 to 18 hours postprocedure. Prominent features were meningismus, fever, sometimes with oculomotor signs and mental confusion. Lumbar puncture revealed a high white cell count, high protein content often with a low glucose level and with absence of organisms. The condition usually started to clear spontaneously about 10 hours after onset, with complete recovery over 2 to 3 days.[Ref]

Very common (10% or more): Headache (may be severe and prolonged)
Common (1% to 10%): Dizziness (2%), neuralgia
Uncommon (0.1% to 1%): Aseptic meningitis syndrome (including chemical meningitis), visual hallucinations, somnolence, hemiparesis, transient ischemic attack, cerebral infarction, syncope
Rare (0.01% to 0.1%): Seizure, neurological changes, drowsiness, transitory peripheral neuropathies (sensory and/or motor or nerve root disturbances, myelitis, persistent leg muscle pain or weakness, 6th nerve palsy, or cauda equina syndrome)
Very rare (less than 0.01%): Dysgeusia (transient metallic taste), disturbance in consciousness, transient contrast-induced encephalopathy (including transient memory loss, coma, stupor, retrograde amnesia), sensory abnormalities (including hypoesthesia), paraesthesia, tremor
Frequency not reported: Syncope vasovagal, motor dysfunction (including speech disorder, aphasia, dysarthria), disorientation, abnormal electroencephalogram, meningism[Ref]


Very common (10% or more): Pain
Common (1% to 10%): Feeling hot
Uncommon (0.1% to 1%): Discomfort, fever, hives
Rare (0.01% to 0.1%): Pyrexia, asthenic conditions (including malaise, fatigue), feeling of heaviness, tinnitus, vertigo
Very rare (less than 0.01%): Shivering (chills)
Frequency not reported: Transient hearing loss[Ref]


Common (1% to 10%): Blood amylase increased
Uncommon (0.1% to 1%): Hypoglycemia in pediatrics (0.3%)
Rare (less than 0.1%): Loss of appetite
Frequency not reported: Iodism[Ref]


Severe pain may often result from undue use of pressure or the injection of large volumes. Joint swelling after injection is less with iohexol (the active ingredient contained in Omnipaque 240) than with high osmolar ionic contrast medium. These types of reactions are generally procedurally dependent and of greater frequency when double-contrast technique is employed.[Ref]

Common (1% to 10%): Back pain
Rare (less than 0.1%): Neck pain, pain in extremity, hypertonia
Frequency not reported: Muscle spasm, arthralgia, arthritis, muscle cramps, fasciculation or myoclonia, spinal convulsion, spasticity, stiff neck[Ref]


Common (1% to 10%): Vision abnormalities (including blurred vision and photomas) (2%)
Uncommon (0.1% to 1%): Nystagmus (less than 0.3%)
Rare (less than 0.1%): Photophobia, ocular muscles weakness
Frequency not reported: Transient cortical blindness[Ref]


Common (1% to 10%): Transient increase in serum creatinine (contrast induced nephropathy may occur)
Rare (less than 0.1%): Impairment of renal function including acute renal failure[Ref]


Uncommon (0.1% to 1%): Angina, chest pain, anemia in pediatrics(0.3%)
Rare (0.01% to 0.1%): Bradycardia, arrhythmia, hypotension, hypertension
Very rare (less than 0.01%): Myocardial infarction, flushing
Frequency not reported: Severe cardiac complications (including cardiac arrest, cardio-respiratory arrest), spasm of coronary arteries, chest pain, shock, arterial spasm, ischemia, thrombophlebitis, thrombosis[Ref]


Uncommon (0.1% to 1%): Urticaria, purpura, abscess, pruritus
Frequency not reported: Severe pustular or exfoliative or bullous dermatitis, Stevens-Johnson syndrome, erythema multiforme, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, rash with eosinophilia and systemic symptoms, psoriasis flare-up[Ref]


Uncommon (0.1% to 1%): Dyspnea, rhinitis, coughing, laryngitis
Rare (0.01% to 0.1%): Cough
Very rare (less than 0.01%): Non-cardiogenic pulmonary edema
Frequency not reported: Severe respiratory symptoms and signs, bronchospasm, laryngospasm, asthma attack[Ref]


Rare (less than 0.1%): Difficulty in micturition[Ref]


The hypersensitivity reactions may appear either immediately after the injection or up to a few days later.
Hypersensitivity reactions may occur irrespectively of the dose and mode of administration, and mild symptoms may represent the first signs of a serious anaphylactoid reaction/shock.[Ref]

Rare (less than 0.1%): Hypersensitivity (including dyspnea, rash, erythema, urticaria, pruritus, skin reaction, vasculitis, angioneurotic edema, laryngeal edema, laryngospasm, bronchospasm or non-cardiogenic pulmonary edema)
Frequency not reported: Anaphylactic/anaphylactoid reaction, anaphylactic/anaphylactoid shock[Ref]


Very rare (less than 0.01%): Sweating
Frequency not reported: Thyrotoxicosis, transient hypothyroidism (premature infants, neonates premature breast fed infant, and in other children)[Ref]


Frequency not reported: Administration site reactions, including extravasation[Ref]


Frequency not reported: Confusion, anxiety[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Omnipaque 180 (iohexol)." Amersham Health, Princeton, NJ.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.