They do work on different (things) and they don't work against each other

Typically Lantus will be prescribed for first thing in the morning or just before bed - it works over a period of 24 hours to control fasting/between meal blood sugars so it's important to take it at the same time every day but not super important "when" (morning or evening or mid day for that matter)

Metformin builds up in your system over a 48 hour period (so you always have at least two days worth of doses floating around)

It works by reducing the amount of sugar your liver releases - no other job - doesn't help with carbs in the food you eat

But it can be a little hard on the stomach so as Henry suggests, taking it with a meal is best "even if it's prescribed for first thing in the morning or whatever"

Because it's in your system for 48 hours whether you take it before bed or before supper, as long as you take it at about the same time everyday, no harm or no less/more effective if you take it at a time other than prescribed

And there is no reason/no harm if you took Metformin and Lantus at the same time - they don't effect one another as far as working and no dangerous interactions

Whatever is most convenient for you and you won't forget to take it will work just fine with those two (drugs) - just keep it consistent

Take metformin with a meal. Good time is when you are home. Be regular and take it at the same time every day. Do not miss doses.

Lantus is a long acting insulin. Take it at the same times every day. Do not miss doses.

Thanks for the info, Graham.🤙