This white, oval pill imprinted with GX CL 2 is a lamotrigine 5 MG Chewable Tablet [Lamictal], per the NIH.
LAMICTAL is a human prescription drug. The active pharmaceutical ingredient is lamotrigine and is classified as, "Anti-epileptic Agent [EPC], Decreased Central Nervous System Disorganized Electrical Activity [PE], Mood Stabilizer [EPC]."
This pill is made by GlaxoSmithKline LLC.
There is 1 other white pill that with a similar imprint: "GX CL 2". They may be a different dosage of the same drug or a different drug entirely.