Iodinated contrast
Ionic agents were developed first and are still in widespread use depending on the requirements but may result in additional complications due to the high concentration of ions (hyperosmolality).
Organic agents which covalently bind the iodine have fewer side effects as they do not dissociate into component molecules.
Most often they are used intravenously, but for various purposes they can also be used intra-arterially, intrathecally (as in diskography of the spine) and intra-abdominally – just about any body cavity or potential space.
[citation needed] Heating non-ionic contrast agent to human body temperature reduces its viscosity.
[5] Diphenhydramine (Benadryl) 50 mg orally or intravenously one hour before contrast administration can reduce the risk of urticaria, angioedema, and respiratory symptoms.
For more severe reactions, including bronchospasm and facial or neck edema, albuterol inhaler, or subcutaneous or IV epinephrine, plus diphenhydramine may be needed.
[citation needed] Anaphylaxis to ionic (high osmolar) contrast agent injections occurred in two clusters of reactions on two occasions (1983 and 1987) in a single radiology clinic in London, Ontario.
[citation needed] A Japanese syringe manufacturer, Terumo, implicated in syringe-related toxic laboratory cell culture effects in Australia in 1981, was instrumental in pro-actively making Japanese disposable syringes and ampoule seals free of natural rubber.
[16] By merchandizing the Katayama series reprints, manufacturers persuaded users worldwide to switch to the almost exclusive use of the expensive nonionic agents.
In 1987, it was the leaching of allergenic MBT from the rubber seals of ionic ampoules that caused a series of allergic reactions (including anaphylaxis) in a radiology office in Canada.
[21] Finally, there is no evidence that adverse skin reactions to iodine-containing topical antiseptics (e.g., povidone-iodine) are of any specific relevance to administration of I.V.
[32] Contrast exposure may interfere with subsequent radioiodine treatment, causing unwanted delays in the management of thyroid cancer.
[30] Previously, beta blockers have been assumed as risk factor for the acquisition of contrast medium-induced adverse reactions/hypersensitivity reactions.
Due to recent investigations it became clear that beta blockers do not increase the frequency of adverse reactions in concert with radiocontrast agents.
[34] Intravenous administration of iodinated radiocontrast agents can cross the placenta and enter the fetal circulation, but animal studies have reported no teratogenic or mutagenic effects from its use.
[35] Nevertheless, it generally is recommended that radiocontrast only be used if absolutely required to obtain additional diagnostic information that will improve the care of the fetus or mother.
[36] Still, mothers who remain concerned about any potential adverse effects to the child are recommended to have the option of abstaining from breastfeeding for 24 hours, with continued milk extraction such as by a breast pump during that period.
