This red, oval pill imprinted with S5 is a Simvastatin 20 MG Oral Tablet, per the NIH.
simvastatin is a human prescription drug. The active pharmaceutical ingredient is simvastatin and is classified as, "HMG-CoA Reductase Inhibitor [EPC], Hydroxymethylglutaryl-CoA Reductase Inhibitors [MoA]."
This pill is made by a total of 8 firms: (1) Accord Healthcare Inc., (2) Preferred Pharmaceuticals, Inc, (3) Unit Dose Services, (4) REMEDYREPACK INC. , (5) H.J. Harkins Company, Inc., (6) St Marys Medical Park Pharmacy, (7) Rebel Distributors Corp, and (8) Bryant Ranch Prepack
There are 2 other red pills that with a similar imprint: "S5". They may be a different dosage of the same drug or a different drug entirely.