Potential Risks of Chronic Sildenafil Use for Priapism in Sickle Cell Disease

Abstract

Introduction Priapism is a common concern in sickle cell disease. With a high frequency of recurrences and serious long-term sequela, a preventative, rather than traditionally reactive approach, needs to be taken in these patients. Reports have shown successful use of sildenafil as a prophylactic treatment but have failed to address adverse outcomes, including vasoocclusive pain crises, of chronic sildenafil therapy in sickle cell patients. Aims We wish to draw attention to the potential adverse outcomes of this therapy on the overall state of the patient's disease for consideration in future studies. Methods We used sildenafil in a patient suffering from almost daily attacks of priapism. Results Sildenafil was successful in decreasing the frequency of priapism; however, our patient experienced an increased frequency of vasoocclusive crises, something not previously addressed. Conclusion Future studies of sildenafil use in sickle cell disease need to assess the global state of the disease, not just the frequency of priapism.

Molecular Pathophysiology of Priapism: Emerging Targets

“…Chronic PDE5 inhibitor therapy has also demonstrated effectiveness where anti-androgenic hormonal agents have been ineffective [82]. However, increased vaso-occlusive episodes were noted in a single case report involving a patient treated with chronic PDE5 inhibitor therapy for SCD-induced priapism [92]. This adverse effect had not been reported in previous case series and cautioned use of the agents in further trials.…”

The effect of sildenafil on the elasticity of erythrocytes in homozygous sickle cell disease

“…[24] Sildenafil has also been reported to be successful in decreasing the frequency of priapism, although there was an increase in the frequency of vaso-occlusive crises. [25] This observation could be attributed to the increased level of cGMP causing vasodilation and reduced erection, while the increased cAMP will result in increased elasticity and reduced deformability that might possibly predispose to increased vaso-occlusive crises. However, Kato [26] reported a limited evidence for sildenafil in treating priapism in sickle cell disease.…”

PAH Therapies in Men: Often Wondered, Seldom Asked

“…2 Prescription information for PDE-5 inhibitors cautions against using these drugs in patients with anatomical deformations of the penis (eg, angulation, cavernosal fibrosis, Peyonie's disease) or in patients with co-morbid conditions potentially predisposing to priapism (multiple myeloma, leukemia, sickle cell disease). Interestingly, PDE-5 inhibitors have been used to treat and prevent ischemic priapism, including in patients with sickle cell disease, [3][4][5] but clearly reflects off-label use. If a patient does experience an erection lasting 4 hours or longer, it is important they seek emergency medical evaluation immediately as untreated priapism may lead to cavernosal fibrosis and permanently impaired erectile function.…”