Recently, cGMP-specific PDE5 inhibitors, specifically tadalafil (CialisTM or AdcircaTM) and sildenafil (ViagraTM or RevatioTM) have been investigated for their potential in ameliorating the functional ischemia in DMD by increasing intracellular levels of cGMP to prolong vasodilation and increase blood flow to tissues. The gene discussed is PDE5A; the disease is Duchenne muscular dystrophy.