Vitamin D3 + Vitamin K2 Phenobarbitone
ModerateVitamin D3 (cholecalciferol) is known to interact with phenobarbital, which is the same medicine as phenobarbitone. The text does not say what the interaction does, only that the two interact when taken together.
These medicines are often taken together with some care. Your doctor may change a dose, space them apart or check on you more often. Make sure your doctor and pharmacist know you take both.