This white, capsule pill imprinted with GG 621 GG 621 is a Terazosin 1 MG Oral Capsule, per the NIH.
Terazosin Hydrochloride is a human prescription drug. The active pharmaceutical ingredient is terazosin hydrochloride and is classified as, "Adrenergic alpha-Antagonists [MoA], alpha-Adrenergic Blocker [EPC]."
This pill is made by Sandoz Inc.
There is 1 other white pill that with a similar imprint: "GG 621 GG 621". They may be a different dosage of the same drug or a different drug entirely.