caa a22 4500 477055915 CHVBK 20180405111346.0 cr unu---uuuuu 170330e19961201xx s 000 0 eng 10.1007/s002280050188 doi (NATIONALLICENCE)springer-10.1007/s002280050188 Mechanisms of tolerance during treatment with nitroglycerin patches for 24 h [Elektronische Daten] [T. O. Klemsdal, H. H. Mundal, K. Gjesdal] Objective: We examined the relationship between tolerance development, counterregulatory responses and arterial vasodilating effects evaluated by digital pulse plethysmography. Methods: Twenty patients with stable angina pectoris were exercise tested before, after 2 and after 24 h of open nitrate patch treatment. Results: The effects observed after 2 h of treatment on exercise duration, ST-segment depression, blood pressure and heart rate were lost in most individuals after 24 h. In contrast, the effects on the arterial pulse curves persisted after 24 h, with a mean change from baseline of 29%, compared to 33% at 2 h. After 24 h, a significant decrease in haematocrit and an increase in body weight were observed. The haematocrit changes correlated with the loss of clinical efficacy (r =0.57 for ST-segment depression, and r =0.54 for exercise duration). Conclusion: Clinical nitrate tolerance may be observed despite maintenance of the arterial vasodilating effects, and tolerance is more related to plasma volume expansion as a counterregulatory mechanism. Springer-Verlag Berlin Heidelberg, 1996 Key words Nitrate nationallicence tolerance nationallicence transdermal nationallicence exercise test nationallicence counterregulation nationallicence digital photoplethysmography nationallicence Klemsdal T. O. Department of Cardiology, Ullevål University Hospital, N-0407 Oslo, Norway, NO aut Mundal H. H. Department of Cardiology, Ullevål University Hospital, N-0407 Oslo, Norway, NO aut Gjesdal K. Department of Cardiology, Ullevål University Hospital, N-0407 Oslo, Norway, NO aut https://doi.org/10.1007/s002280050188 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002280050188 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Klemsdal T. O. Department of Cardiology, Ullevål University Hospital, N-0407 Oslo, Norway, NO aut NATIONALLICENCE 700 1- Mundal H. H. Department of Cardiology, Ullevål University Hospital, N-0407 Oslo, Norway, NO aut NATIONALLICENCE 700 1- Gjesdal K. Department of Cardiology, Ullevål University Hospital, N-0407 Oslo, Norway, NO aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer