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Sildenafil inside the treating raynauds phenomenon resistance against vasodilatory therapy

This study demonstrates that sildenafil significantly improves microcirculation in patients with Raynauds phenomenon resistant
to therapy with vasodilators. After administration of 50 mg sildenafil 2 times a day during Month, mean capillary blood cell
velocity more than quadrupled in patients with secondary Raynauds phenomenon. Akin to this, occurrence and duration
of warning signs of Raynauds phenomenon decreased considerably, thus producing significantly better well-being of the sufferers. These results confirm recent case reports on successful occasional by using sildenafil in patients with Raynauds phenomenon. 10,13

Raynauds phenomenon occurs due to vasoconstriction from the digital arteries, precapillary arterioles, and cutaneous
arteriovenous shunts, causing digital ischemia. buy zyban without a prescription N . o . (NO) based on the vascular endothelium plays an essential
role in the damaging peripheral vasomotor tone14 and has now demonstrated an ability to become associated with initiation and repair off penile erection. 15 NO activates guanylate cyclase, which leads to a rise of cGMP. cGMP is hydrolyzed by phosphodiesterases (PDEs), in
particular by the cGMP-specific PDE-5 isoenzyme. Sildenafil is really a highly selective and potent inhibitor of PDE-5, that elevates
cGMP, causing enhanced vasorelaxation. Furthermore, the NO/cGMP pathway resists -mediated vasoconstriction, which could
intensify its vasorelaxing properties. 16 Sildenafil is shown to perform the job within the cure for impotence problems. 4,5 Its effect just isn't restricted to the corpus cavernosum, however, as PDE-5 exists in lots of other tissues. Therefore, sildenafil
acts in a variety of different disorders. It reduces, for example, pulmonary and systemic pressure,610,17 relaxes saphenous veins and pectoral arteries,18 and increases flow-mediated forearm circulation in patients with chronic heart failure,19 diabetes,20 and coronary heart. 21

The effects of sildenafil on microvascular disorders for example Raynauds phenomenon weren't subject of controlled studies. In our study, capillary the flow of blood was severely impaired and quite often hardly detectable in patients with Raynauds
phenomenon. Sildenafil resulted in a >400% increase of flow velocity. As capillaries haven't any smooth muscle cells, capillary flow
velocity depends mainly within the vasomotor tone from the arterioles. Relaxation of the arterioles leads to better capillary
filling pressure and capillary blood cell velocity. Besides these effects on vascular function, sildenafil-associated
inhibition of platelet activation, as reported recently,21,22 would have led to the improvement of microcirculation and warning signs of Raynauds phenomenon. Furthermore, central
effects, one example is, improvement of cardiac output and/or oxygenation, probably have played a task.

One might argue the short half-life of sildenafil (about 4 hours) would limit its clinical use. Our data on capillary blood
flow velocity, however, plus the marked reduction of symptoms, come in favor of prolonged functional effects exceeding
the plasma half-life of sildenafil. This really is held by recent findings that report improvement of flow-mediated brachial
artery dilation A day after the last dose of sildenafil. 20 After statements of our own patients, they perceived the impact on digital microcirculation continued about 2 weeks after sildenafil
treatment was been stopped. Nevertheless, treatment affect on clinical symptoms and capillary flow velocity had not been dependent
on randomization order, indicating that this washout period was sufficiently long. The fact all patients correctly identified
whenever they were on treatment with sildenafil or placebo certainly limited blinding of the study and may have influenced patient
statements inside their daily questionnaires. This can be also exactly why no uncomfortable side effects were reported during placebo treatment. However, corresponding improvement of capillary flow velocity is objectified by circulation measurements and partial
healing of digital ulcera.

Although only patients with severe Raynauds phenomenon were in the study, symptoms remained overall relatively low. This really is explained by the fact that the investigation was performed during summer 2003, which was characterized by a reliable and extraordinary
warm climate in middle Europe. One might object that symptom scores during therapy with sildenafil and placebo will not be
comparable without temperature and activity control. However, such control can't be performed in every day life. Considering
the stable meteorologic conditions throughout the study period, it is extremely unlikely that significant improvement of Raynauds
Condition Score was caused by differences in ambient temperature.

One can think that sildenafil can be well tolerated generally in most patients with Raynauds phenomenon. On this study, only 2 patients
interrupted therapy with sildenafil as a consequence of treatment-related symptoms, and something of which restarted therapy later without
unwanted effects.

Overall, our results demonstrate the very first time inside a randomized study the efficacy of treatment with sildenafil on microcirculation
and symptoms in patients with therapy-resistant Raynauds phenomenon. PDE-5 inhibition is apparently a good new approach
in patients with microcirculatory disorders.