This blue, diamond pill imprinted with VGR 25 Pfizer is a sildenafil 25 MG Oral Tablet [Viagra], per the NIH.
Viagra is a human prescription drug. The active pharmaceutical ingredient is sildenafil citrate and is classified as, "Phosphodiesterase 5 Inhibitor [EPC], Phosphodiesterase 5 Inhibitors [MoA]."
This pill is made by Pfizer Laboratories, Division of Pfizer Inc.
There is 1 other blue pill that with a similar imprint: "VGR 25 Pfizer". They may be a different dosage of the same drug or a different drug entirely.