Quality of extemporaneously compounded nitroglycerin ointment

PURPOSE: Published clinical trials support the use of 0.2 to 0.4 percent nitroglycerin ointment for the treatment of an anal fissure, although no product is yet available in the United States. In 2004, 84,000 prescriptions were written for compounded nitroglycerin ointment. This study was designed to evaluate the quality of extemporaneously compounded nitroglycerin ointment. METHODS: Prescriptions for 0.3 percent nitroglycerin ointment were filled at retail pharmacies and shipped to analytical laboratory for analysis by their validated method. RESULTS: Five of 24 (20.8 percent) samples did not meet the United States Pharmacopoeia requirement for content uniformity of 90 to 110 percent and <6 percent relative standard deviation. Seven of 24 samples (29.2 percent) were subpotent based on the United States Pharmacopoeia requirement of 90 to 115 percent of label claim, and 1 sample was suprapotent. When considered for potency and/or content uniformity, 11 of 24 (45.8 percent) were misbranded and poor quality. CONCLUSIONS: Forty-six percent of the nitroglycerin ointment products compounded by 24 pharmacies did not meet the United States Pharmacopoeia specifications for potency and/or content uniformity when filling a prescription for 0.3 percent nitroglycerin ointment. These results raise significant issues regarding whether patients are put at undue risk relative to the relief of anal fissure pain. The pain associated with chronic anal fissure is severe, often debilitating, and may affect the patient's ability to work.