Tazzle, likely referring to a medication like Tadalafil (brand name Cialis), affects blood flow in the body primarily due to its mechanism of action as a phosphodiesterase type 5 (PDE5) inhibitor. Here’s how it works:

1. PDE5 Inhibition: Tazzle inhibits the enzyme PDE5, which is responsible for breaking down cyclic guanosine monophosphate (cGMP). cGMP is a molecule that relaxes smooth muscle cells and widens blood vessels, allowing increased blood flow to specific areas of the body.
   
2. Relaxation of Smooth Muscle: By inhibiting PDE5, Tazzle increases the levels of cGMP in the smooth muscle cells of blood vessels in the penis (in the case of erectile dysfunction treatment) and also in other parts of the body (for treating pulmonary arterial hypertension).
   
3. Increased Blood Flow: The increased cGMP levels lead to relaxation of smooth muscle cells and dilation of blood vessels, which results in improved blood flow. In the penis, this allows for better erectile function by facilitating the inflow of blood during sexual stimulation. In pulmonary arterial hypertension, it reduces the workload of the heart by relaxing the blood vessels in the lungs, thereby improving exercise capacity.
   

Thus, Tazzle (Tadalafil) affects blood flow by enhancing the natural process of vasodilation through inhibition of PDE5, leading to improved circulation in specific areas of the body as needed for the treatment of erectile dysfunction and pulmonary arterial hypertension.