Abstract
Aim. This study was carried out to compare the effect of trinitroglycerin (TNG) spray and sublingual pearl on chest pain severity and some physiological indices of people with chest pain visited by emergency medical services.
Background. Glyceryl trinitrate is used as an anti-anginal vasodilating agent with various forms including spray and pearl with probable different therapeutic effects.
Method. In this quasi-experimental study, 80 patients with chest pain were recruited through convenience sampling and then allocated to pearl and spray groups by minimization method. After arriving at the patient's bedside, vital signs and chest pain severity were measured and recorded, then the drug was administered every 5 minutes for 3 times; thereafter, the measurements were repeated. The data analyzed in SPSS software 1) using descriptive and inferential statistics.
Findings. The results showed that after intervention, the mean score of pain in pearl and spray groups were 6.05±0.98 and 5.60±1.25, respectively. There was no statistically significant difference between groups in terms of pain score. Whereas after intervention, the mean systolic and diastolic pressure in pearl group was significantly lower than the spray group, the heart rate in both groups were increased.  
Conclusion. Nitroglycerin in the pearl form has the same effect as spray form in relieving chest pain. According to the circumstances and drug accessibility, emergency staff might use every two forms of Nitroglycerin.