6. Patients who have received an ACE (angiotensin converting enzyme) inhibitor within the last 24 hours should not be treated. Patients receiving an ACE inhibitor may experience an anaphylactoid-like reaction, including hypotension associated with flushing, dyspnea, and bradycardia. Such reactions, if left untreated, may be life-threatening. The administration of ACE inhibitors also has been associated with the occurrence of tachycardia. Risk of an anaphylactoid-like reaction or tachycardia may be minimized by the temporary cessation of the administration of ACE inhibitors for 6 days or longer before initiating the treatment protocol.