Iohexol does not influence the levels of blood serum cation electrolytes during intravenous pyelography

PURPOSE: The influence of the nonionic contrast agent iohexol on blood pH and the cation electrolytes Ca, Na, K and Mg was studied in vivo in humans during the intravenous pyelography. MATERIAL AND METHODS: A population of 28 patients without renal function impairment or electrolyte imbalance was divided into two equal groups. The first group received an intravenous injection of 0.6 mL Omnipaque per kg of body weight (0.388g iohexol/kg and 0.18 g iodine/kg). The second group received a double dose of Omnipaque (1.2 mL iohexol/kg; 0.776g iohexol/kg and 0.36g iodine/kg). Blood samples (5 mL) were taken before the injection of the contrast medium and 5, 10 and 20 minutes (marking the end of the examination) after the injection. Blood pH was also determined immediately after each sample collection, while electrolytes were measured in the laboratory. Systolic and diastolic blood pressure were also determined simultaneously with each sample collection using a mercury manometer. RESULTS: Iohexol in simple and double doses did not have any statistically significant effect either on blood pH or on blood serum electrolytes during intravenous pyelography. Blood pressure, both systolic and diastolic, remained stable in all the patients during the examination. CONCLUSIONS: Our results show that the nonionic contrast medium iohexol at the doses used in routine intravenous pyelography does not have any influence on blood pH and serum cardioactive cation electrolytes in humans. An electrolyte imbalance is always a risk factor that may contribute to the development of cardiovascular side effects. This factor is eliminated when iohexol is administered intravenously instead of an ionic agent.