Self-administration of untested medical therapy for treatment of prostate cancer can lead to clinically significant adverse events

Self-administration of untested medical therapies such as supraphysiologic doses of vitamins and minerals or herbal mixtures have become increasingly popular during the past decade among patients with prostate cancer (1). Although the potential impact of some of these interventions on prostate cancer prevention is an area of current investigation (2), they also have the ability to confound the results of conventional or investigational therapies by affecting serum tumor markers (e.g., prostate-specific antigen) and may cause clinically significant adverse effects (3). We describe a case in which the use of a supraphysiologic dose of niacin could have led to a serious and possibly life-threatening intraoperative hemorrhage during conventional prostate cancer therapy. The etiology of this potential untoward event was believed to be due to a drug interaction between the high dose of niacin and a routinely administered preoperative antibiotic. The patient was a 55-year-old man who presented to the Dana Farber Cancer Institute for discussion of treatment options for his clinically localized prostate cancer. His most recent prostate-specific antigen level was 6.5 ng/dL in November 2001. The results of his transrectal ultrasoundguided needle prostate biopsy revealed that one of nine biopsy cores contained Gleason score 3 4 prostate cancer (4). His digital rectal examination revealed a smooth prostate bilaterally with no discernible nodules. His staging studies included an endorectal MRI study of the pelvis and prostate and was read by an MR radiologist as showing no evidence of extraprostatic disease or enlarged pelvic lymph nodes. His past medical history was notable for a silent myocardial infarction over the anteroseptal distribution in April 2000 for which he underwent a coronary artery bypass graft 1 in June 2000. Subsequently, he underwent a maximal treadmill exercise test in February 2002 showing no evidence of ischemia. He had hypercholesterolemia and had had rheumatic fever at age 5 years and had undergone bilateral tonsillectomy at age 4 years. He had no known drug allergies, no tobacco use, and social ethanol use. His only prescribed medications were Pravachol 10 mg p.o. every bedtime and aspirin 325 mg p.o. daily. In addition, each day he was taking nonprescription medicines consisting of the first nine items listed in Table 1, as well as two of the “Max for Men Multivitamins” and one of the mixed carotenoid capsules daily. After a discussion of all the treatment options for his clinically localized and low-risk prostate cancer, including radical prostatectomy, conformal external beam radiotherapy, and prostate brachytherapy, he elected to undergo MRI-guided prostate brachytherapy (5) planned for February 27, 2002. On February 20, 2002, 1 week before the planned procedure date, the patient came to the Brigham and Women’s Hospital for preadmission testing that included a chest X-ray, electrocardiogram, electrolytes, blood urea nitrogen, creatinine, liver function tests, complete blood count, and a basic coagulation profile. All studies were normal, except for a prothrombin time of 17.0 s (normal range 11.4–14.4). Given this abnormal laboratory finding, all medications were stopped, and the plan was to obtain a prothrombin time on the morning of the procedure (February 27, 2002) and perform a reevaluation. As part of the preoperative protocol, the patient was instructed to take 4 mg of Decadron and 150 mg of Zantac b.i.d. orally 1 day before the procedure. The Decadron was prescribed to decrease the risk of acute urinary retention by minimizing the amount of prostate edema that occurs during the first few weeks postoperatively as a result of the transperineal insertion of 20 –30 15-cm long 18-gauge needles into the prostate gland