Nevertheless the preventive measurements can reduce the risk.

1. In a patient with risk factors (to evaluate previously with the table 2 (Contrasts: Factors of Risk)), to think the possibility of using other skills (as gammagrafía isotópica or ultrasound scan) to obtain diagnostic information with minor risk.
2. To hydrate appropriately the patient, to diminish the risk of sharp renal insufficiency, in the predisposed subjects (although there have taken place cases of sharp renal insufficiency in well hydrated patients).
3. To control carefully the renal function earlier and after the study in patients of high renal risk, so that the treatment of support of the sharp renal insufficiency could be instituted as soon as possible.
4. To reduce the risk of pulmonary edema in the patients with cardiopatía, to avoid the sodium salt in the contrast means.
5. To control electrocardiográficamente the cardiac patients during the procedure, to diagnose and to treat precozmente the potentially fatal cardiac arrhythmias.
6. Since it refers to the prevention of the reactions anafilactoides, if the study with MCR is essential, the risk and probably the gravity of a possible reaction they can diminish by means of a previous treatment with antihistamines and corticosteroides:
   • To administer Prednisona 40 mg orally, every 6 hours, beginning 18 hours before the exploration, and Clorfeniramina (Polaramine ®) 1 blister IV 15 min. earlier.
   • Whenever a MCR is administered to a patient with history of previous reaction, to obtain his assent with cause knowledge.
   • The patients can talk each other previously with previous diverse reactions, like morning sickness, vomiting, sudden facial reddening, although these types of reaction do not increase the risk of a later adverse reaction.
   • To remember that even after a previous treatment reactions can take place anafilactoideas serious for MCR. Therefore, the repetition of the study must be considered to be essential, the study must be practised under careful observation and has to prepare immediately of the necessary means and the personnel to treat a possible adverse reaction.
   • He must not entrust himself in the previous treatment for the prevention of the cardiopulmonares reactions, convulsions and renal insufficiency, since he lacks prophylactic efficacy.
   • The contrast means iodados of fall osmolaridad diminish the risk of the adverse reactions in general.