The alternative to metformin for high fasting blood glucose numbers is long acting insulin. But since many are afraid of insulin, it usually becomes the medication of last resort. Doctors will go through the gamet of medications to try to help over time.

I suppose you are type 2. First some questions.
What is your A1C.
Metformin is usually the first line of defense, but treatment types are usually dictated by your A1C. Doctors use a flow chart to determine treatment medications.

A good starting point begins with you doing some of the hard work:
Cutting out all added sugars in food and drink.
Cutting carbs to one serving, 15 carbs, per meal.
Cutting out all processed carbs, white carbs.
White flour,
White pasta,
White bread,
White potatoes,
White rice.
Substitute whole grains and high fiber carbs.

Baby steps. Start with one and keep doing it. When you are ready do another and keep doing it. Soon you are on your way.

Be the warrior you never knew you were. Do what's necessary. Live your life on your terms. Fight the good fight. Control your diabetes journey and don't let diabetes control your life.

I wish for you more good days than bad and have many exceptional days too.

And never give up, never surrender, never ever.
You got this.
Have a blessed day.