Methods of Preventing IV Contrast Reactions

GENERAL PRINCIPLES TO "PREVENT IV CONTRAST REACTIONS"

Adverse reactions can be reduced if general principles are applied to all patients. The smallest amount of contrast agent possible should be used for each procedure. Allowing at least 48 hours to elapse between procedures in which contrast material is used enables the kidneys to recover.

Methods of Preventing Contrast Material–Induced Renal Insufficiency

General principles	Use the smallest amount of contrast material possible.
	Discontinue other nephrotoxic medications before the procedure.
	Allow two to five days between procedures requiring contrast material.
Hydration	Oral: 500 mL before the procedure and 2,500 mL over the 24 hours after the procedure
	Intravenous: 0.9% or 0.45% saline, 100 mL per hour beginning four hours before the procedure and continuing for the 24 hours after the procedure
Calcium channel blockers	Nitrendipine (Baypress), 20 mg orally daily for three days beginning 24 hours before the procedure

HYDRATION (to Prevent IV Contrast Reactions)

It has been well documented that hydration minimizes, or decreases, the incidence of renal failure induced by contrast material. Unless contraindicated, infusion of 0.45 or 0.9 percent saline at a rate of 100 mL per hour beginning four hours before the procedure and continuing for 24 hours after the procedure, is recommended.

In patients able to take oral fluids, hydration can be achieved through ingestion of 500 mL of fluid before the procedure followed by 2,500 mL over the 24 hours after the procedure. There have been no prospective studies comparing different fluids for hydration.

CORTICOSTEROIDS (TO PREVENT IV CONTRAST REACTIONS)

Nonrenal reactions to contrast material can be reduced by premedicating the patient with corticosteroids. [Reference Evidence level A, randomized controlled trial (RCT); Reference Evidence level B, uncontrolled study] This protective effect functions for ionic and nonionic contrast materials. Many physicians give corticosteroids only to patients known to have a previous history of idiosyncratic adverse reactions.

Combining corticosteroid use with a histamine H1- receptor blocker further reduces the chance that adverse reactions will develop. Adverse reactions decreased from a range of 17 to 35 percent to a range of 5 to 10 percent when corticosteroids were combined with an H1 blocker (diphenhydramine).[References  and Evidence level B, uncontrolled study]

The following premedication protocol has been recommended for use in patients with a history of idiosyncratic reactions: methylprednisolone (one 32-mg tablet at 12 hours and two hours before the study) or prednisone (one 50-mg tablet at 13 hours, seven hours, and one hour before the study). If the previous reaction was moderate or severe or included a respiratory component, the physician can add the following: an H1 blocker such as diphenhydramine (one 50-mg tablet one hour before the study) and an H2 blocker (optional) such as cimetidine (Tagamet), one 300-mg tablet one hour before the study, or ranitidine (Zantac), one 50-mg tablet one hour before the study. Using an H2 blocker without also using an H1 blocker is not recommended.

OTHER DRUGS

Mannitol (to Prevent IV Contrast Reactions))

Mannitol (Resectisol) has been used in an attempt to increase or maintain the glomerular filtration rate (GFR) during radiographic studies using contrast media. Very little supporting evidence shows that mannitol maintains GFR during hypoperfusion. A study that compared hydration with saline alone versus saline plus mannitol showed that saline alone was more protective.

Furosemide (to Prevent IV Contrast Reactions))

Furosemide (Lasix) has not been shown to prevent contrast-induced renal failure. A significant decline in renal function occurred in patients treated with furosemide before contrast administration. Negative fluid balance caused a decrease in renal cortical and medullary blood flow, leading to hypoxia.

Calcium Channel Blockers (to Prevent IV Contrast Reactions))

Oral administration of calcium channel blockers was shown to minimize reduction of GFR. In a prospective study, patients were treated with 20 mg per day of nitrendipine for three doses starting 24 hours before the procedure. Some sparing of GFR was noted in these patients compared with patients who did not receive calcium channel blockers

ACR-Proposed Premedication Regimen to Reduce Contrast Reactions

According to the version #7 (2010) ACR Manual on Contrast Media, the following regimens are recommended for premedication of patients at risk for developing contrast reaction.

Elective Premedication(to Prevent IV Contrast Reactions)

1. Prednisolone: 50 mg PO at 13 hours, 7 hours and 1 hour before contrast media injection, PLUS Diphenhydramine 50 mg IV, IM or PO 1 hour before contrast medium OR
2. Methylprednisolone 32 mg PO 12 hours and 2 hours before contrast media injection. An anti-histamine (as in option 1) can be added. If unable to take oral medication, use hydrocortisone 200 mg IV instead

Emergency Premedication (to Prevent IV Contrast Reactions)

1. Methylprednisolone 40 mg or hydrocortisone 200 mg IV every 4 hours until contrast study required PLUS Diphenhydramine 50 mg IV 1 hour prior to contrast injection OR
2. Dexamethasone 7.5 mg or betamethasone 6 mg IV every 4 hours until contrast study PLUS diphenhydramine 50 mg IV 1 hour prior to contrast injection OR
3. Omit steroid entirely and give diphenhydramine 50 mg IV

"IV steroids have not been shown to be effective when administered less than 4 to 6 hours prior to contrast injection."