What the label lists and what reports show
Iohexol side effects
Iohexol's FDA label: “Most common adverse reactions (incidence ≥ 1%) in adult patients Intrathecal: Headaches, pain including backache, neckache, stiffness and neuralgia, nausea, vomiting, dizziness Intra-arterial or intravenous: Pain, vision abnormalities (including blurred …” FAERS holds 8,244 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is urticaria (1,006 reports).
- Generic listed
- Boxed warning
Check it at the source: the iohexol FDA label on DailyMed (effective April 7, 2026, GE Healthcare Inc.); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (incidence ≥ 1%) in adult patients Intrathecal: Headaches, pain including backache, neckache, stiffness and neuralgia, nausea, vomiting, dizziness Intra-arterial or intravenous: Pain, vision abnormalities (including blurred vision and photomas), headache, taste perversion, arrhythmias including premature ventricular contractions (PVCs) and premature atrial contractions (PACs) […]
Table 16. Adverse Reactions (≥1%) in in Adult Patients Following Intrathecal Administration of OMNIPAQUE in Clinical Trials
| Adverse Reaction | Incidence N=1,531 |
|---|---|
| Headaches | 18% |
| Pain including backache, neckache, stiffness, neuralgia | 8% |
| Nausea | 6% |
| Dizziness | 2% |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following clinically significant adverse reactions are described elsewhere in the labeling: Risks Associated with Intrathecal Administration of OMNIPAQUE Injection 140 mg Iodine/mL and 350 mg Iodine/mL [see Warnings and Precautions (5.1) ] Risks Associated with Parenteral Administration of OMNIPAQUE Oral Solution [see Warnings and Precautions (5.2) ] Hypersensitivity Reactions [see Warnings and Precautions (5.3) ] Acute Kidney Injury [see Warnings and Precautions (5.4) ] Cardiovascular Adverse Reactions [see Warnings and Precautions (5.5) ] Thromboembolic Events [ see Warnings and Precautions (5.6) ] Thyroid Dysfunction in Pediatric Patients 0 to 3 Years of Age [see Warnings and Precautions (5.9) ] Severe Cutaneous Adverse Reactions [see Warnings and Precautions (5.12) ] Most common adverse reactions (incidence ≥ 1%) in adult patients Intrathecal: Headaches, pain including backache, neckache, stiffness and neuralgia, nausea, vomiting, dizziness Intra-arterial or intravenous: Pain, vision abnormalities (including blurred vision and photomas), headache, taste perversion, arrhythmias including premature ventricular contractions (PVCs) and premature atrial contractions (PACs), angina/chest pain, nausea Oral: Diarrhea, nausea, vomiting, abdominal pain, flatulence, headache Body Cavity: Pain, swelling, heat sensation ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact GE …
Source: FDA drug label, GE Healthcare Inc., effective April 7, 2026 (SPL set eee15ebe-d349-4497-acef-6abe7a8247fb), via openFDA; the full label on DailyMed
What do FAERS reports show?
8,244 reports list iohexol among the medicines taken, each a report of something that happened, not proof the medicine caused it; 488 are coded as a death and 2,707 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 25 reactions below, 18 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Iohexol: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions