Could you tell me what happens if you take 2 tablets of expired minocycline?

Not much: The expiration date on this and many drugs is simply the date at which the drug company will not longer guarantee the potency is within 5% of that on the label. An expired drug can be ok or may be a little less potent. I known of no drug that expires to become toxic. So at worst, you have taken something with a little less potency than you might have wanted.

Expired minocycline: Minocycline belongs to a class of antibiotics called tetracyclines. Expired tetracycline class antibiotics have to be discarded because they can become toxic and can result in kidney damage. Please call call 1-800-222-1222 american association of poison control centers as soon as possible.