Primary Outcome Measures:
- The maximum tolerated dose and toxicity profile of sildenafil treatment in patients with subacute ischemic stroke. [ Time Frame: 2 weeks ] [ Designated as safety issue: Yes ]
Secondary Outcome Measures:
- The estimated efficacy of sildenafil in comparison with concurrent patients not enrolled in the study (otherwise eligible but decline participation). [ Time Frame: 3 months ] [ Designated as safety issue: No ]
Stroke is the third leading cause of death and the leading cause of serious longterm disability in the United States. Approximately 15-30% of stroke survivors are permanently disabled. Twenty eight percent of stroke patients are under age 65 which results in a loss of work income. While many restorative therapies are touted as promising for the treatment of ischemic stroke, to date none are approved for this purpose. Sildenafil (Viagra®), a phosphodiesterase type 5 inhibitor, has been shown to reduce mortality and improve the functional outcomes of young and aged rats when administered 24 hours and 7 days after stroke onset. Such results are encouraging and warrant further investigation in human stroke.
The specific aims of this study are to assess the safety of treating ischemic stroke patients with sildenafil (Viagra®) and to evaluate their outcomes at day 90. This will be a phase I dose-escalation study with cohort sizes of 12 patients (depending on the occurrence of serious adverse events). A total enrollment of 72 patients is planned. Patients who are between 4 and 7 days from stroke onset will receive 25, 50, 75, 100, 125, or 150 mg daily of sildenafil for a period of 14 days. Evaluation of potential toxicity will be monitored throughout the course of treatment and during a formal visit at day 16 after initiation of treatment. Evaluation of potential toxicity will be monitored throughout the course of treatment. Follow-up visits will take place at days 30, 60, and 90. Plasma and serum monitoring of vascular endothelial growth factor (VEGF) will be made prior to treatment, at days 7, 16, 30, 60, and 90. Measurements of NIHSS scores, Rankin scores, and Barthel indices will be made at days 30, 60, and 90. Patients will also be assessed for color vision changes and sexual function during day 16 and day 90 visits.
There will be every other day phone calls to patients while on treatment. The primary outcome measure will be death, recurrent stroke, myocardial infarction, and neurological worsening during treatment. Exploratory analysis will include functional outcomes on neurological scales and changes in VEGF levels in relation to clinical outcome.
The long-term objective is to identify a safe and easily administered treatment that improves functional outcome in patients with ischemic stroke.