What is the expiration date of a bottle of metformin labeled 3/19?

The expiration date indicated on a medication bottle is typically understood to refer to the last day of the month specified. In this case, a label showing 3/19 signifies March 2019. Therefore, the expiration is interpreted as the end of March, which would be March 31, 2019.

Thus, any medication labeled in this manner is valid and effective up until the end of the month stated, meaning it remains safe and effective until March 31, 2019. It is critical for pharmacy professionals to be aware of this standard interpretation to ensure proper patient safety and medication effectiveness.