It is difficult to assess acute therapeutic intervention therapy, particularly in patients with unstable angina. Our aim was to evaluate the feasibility of a pain-scoring method and to compare the response to sublingual administration of an isosorbide dinitrate (ISDN) tablet, ISDN spray or nitroglycerin (NTG) spray. Pain scoring was assessed by the subjective grading of the patients’ pain severity from 1 to 10. We studied 205 patients (mean age 66 ± 13 years). Pain attenuation, defined as at least 50% reduction in pain intensity, occurred in the ISDN tablet, ISDN spray and NTG spray groups after 360 ± 290, 318 ± 289 and 233 ± 271 s, respectively (p = 0.0005). In conclusion, pain scoring is a feasible and useful clinical method to assess antianginal therapy in unstable angina patients. Sublingual nitrate sprays, particularly NTG, seem to alleviate anginal pain faster than ISDN tablets in this patient population.