THE FOLLOWING DRUGS HAVE THE POTENTIAL TO DECREASE THE UPTAKE OF NOREPINEPHRINE AND CAUSE FALSE NEGATIVE IMAGING RESULTS: ANTIHYPERTENSIVES THAT DEPLETE NOREPINEPHRINE STORES OR INHIBIT REUPTAKE (E.G., RESERPINE, LABETALOL), ANTIDEPRESSANTS THAT INHIBIT NOREPINEPHRINE TRANSPORTER FUNCTION (E.G., AMITRIPTYLINE AND DERIVATIVES, IMIPRAMINE AND DERIVATIVES, SELECTIVE SEROTONIN REUPTAKE INHIBITORS), SYMPATHOMIMETIC AMINES (E.G., PHENYLEPHRINE, PHENYLPROPANOLAMINE, PSEUDOEPHEDRINE AND EPHEDRINE), AND COCAINE. INCREASING THE DOSE OF IOBENGUANE I-123 INJECTION WILL NOT OVERCOME ANY POTENTIAL UPTAKE LIMITING EFFECT OF THESE DRUGS. BEFORE TEST, DISCONTINUE (FOR AT LEAST 5 BIOLOGICAL HALF-LIVES) DRUGS KNOWN OR EXPECTED TO REDUCE NOREPINEPHRINE UPTAKE, AS CLINICALLY TOLERATED.