metrizoic acid metrizoic acid metrizoic acid is a pharmaceutical drug that was used as an iodinated contrast medium for x-ray imaging. its uses included angiography (imaging of blood vessels and heart chambers) and urography (imaging of the urinary tract), but it has been discontinued, at least in the us. metrizoic acidclinical dataatc codev08aa02 (who) identifiers iupac name 3-(acetylamino)-5--2,4,6-triiodobenzoic acid cas number1949-45-7pubchem cid2528drugbankdb09346chemspider2433uniicm1n99qr1mkeggc14165chebichebi:34847chemblchembl1736 ycomptox dashboard (epa)dtxsid6023311 echa infocard100.016.147 chemical and physical dataformulac12h11i3n2o4molar mass627.943 g·mol−13d model (jsmol)interactive image smiles cc(=o)nc1=c(c(=c(c(=c1i)c(=o)o)i)n(c)c(=o)c)i inchi inchi=1s/c12h11i3n2o4/c1-4(18)16-10-7(13)6(12(20)21)8(14)11(9(10)15)17(3)5(2)19/h1-3h3,(h,16,18)(h,20,21)key:gggdnpwhmnjrfn-uhfffaoysa-n it was used in form of its salts, metrizoates. due to its high osmolality, metrizoic acid had a risk of inducing allergic reactions higher than that of lower osmolar contrast media. chemistry the iodine content of metrizoate ranged from 370 mg/ml to 440 mg/ml, with osmolarity has high as 2100 mosm/kg. the viscosity is 3.4 cp at 37 degree celsius (human body temperature). adverse effects side effects of metrizoate are: urticaria, headache, nausea, vomiting, dizziness, and hypotension. other side effects include minor electrocardiographic changes such as tachycardia, bradycardia, and inversion of t waves.