Can I take fluconazole if I take metformin?

They do not interact, so I do not see a problem with you taking both.

Now, if the same Dr. prescribed the antifungal along with the metformin he/she is most likely to know about potential interactions, in this case there are none. But if two separate Drs. are prescribing without them knowing you are taking one medication or the other, it would be beneficial for you to inform them, for your own safety.

Interaction report:

https://www.drugs.com/interactions-check.php?drug_list=1096-0,1573-0