Many forms of intravascular contrast media have been used to enhance medical imaging. Their value has long been recognized, as confirmed by their daily use in radiology departments around the world. However, like all pharmaceuticals, these agents are poisons and are not completely risk-free (American College of Radiology, 2013). The degree of safety of contrast media depends on their composition. There are different types of contrast that vary in composition. Due to their chemical properties, contrast media generally have a higher osmolality and are thicker (viscosity) than blood or spinal fluid. Therefore, osmolality and viscosity affect the safety of the contrast medium because they play a role in the development of contrast reactions. Additionally, various adverse effects attributed to intravascular iodinated contrast media appear to be related to osmolality. This includes allergic reactions, fluid shifts, physiological side effects, sensation of heat, and any complications following contrast extravasation (Journal of Nuclear Medicine Technology, 2008). It has been noted that as osmolality increases, the risk of adverse reaction becomes more likely due to the high toxicity of the contrast agent. The toxicity of the contrast agent tends to decrease as the osmolality approaches that of blood serum, as shown by a non-ionic contrast agent, for example Omnipaque (ACR, 2013). Therefore, the lower the osmolality, the safer the contrast medium. Additionally, as Chapman and Nakielny state, “low osmolar and iso-osmolar contrast media are 5 to 10 times safer than high osmolality contrast media.” Likewise, there is a notable variation in the osmolality of contrast products and therefore their safety for the patient, depending on its ion...... middle of paper ......f contrast (ACR, 2012). It is also essential that the radiologist performs a pre-check of the medication before administering the contrast medium. This involves checking the name, concentration, dose administered, expiry date, batch number, color/appearance and seal of the bottle. If these aspects are not properly checked, it could affect the safety of contrast media. In conclusion, it clearly appears that intravascular contrast products are essential to the practice of radiology. Although contrast media are widely used and cause few side effects, reactions can occur, as with any pharmaceutical product. However, these reactions are rare, so the benefit of contrast during examinations far outweighs the risk. Thus, intravascular contrast agents can be used safely in most patients and should not be neglected because a limited number of patients react to them...