Nitrate-Induced Headache and Blood Urea Nitrogen: An Interesting Interaction between Two Nitrogen Compounds

Abstract Nitrates, being one of the most widely used and effective drugs for relief of angina pectoris in all spectra of coronary artery disease (CAD), have the potential to induce headaches similar to migraine. We aimed to assess the possible predictors and associates of nitrate-induced headache (NIH) in patients with CAD who were given sublingual nitrates during coronary angiography (CAG). Two hundred and forty-four patients who had received sublingual isosorbide dinitrate during the CAG procedure for various reasons and had fulfilled the inclusion criteria comprised the study population. All patients were instructed to tell the health care providers for the occurrence of headaches during in-hospital follow-up period. NIH was defined as a headache occurring 0.5 to 3 hours after administration of sublingual isosorbide dinitrate. Patients with and without NIH were compared with respect to their demographic, clinical characteristics, and laboratory parameters. Among those 244 patients, 25 had NIH, and the remaining 219 patients did not report any headaches. There were no statistically significant differences between the two groups regarding the demographic, clinical characteristics, and laboratory parameters except the blood urea nitrogen (BUN), which was found to be significantly lower in patients with NIH than in those without NIH. Logistic regression analysis also revealed an independent but inverse association between NIH and BUN levels. This study demonstrates that NIH following sublingual isosorbide dinitrate administration is independently and inversely associated with BUN levels.