Q: Beside dipyridamole (Persantine), name at least one drug in which dose of  adenosine should be decreased?

Answer: Diazepam (Valium)

Though experimental but due to potential chance of drug interaction, adenosine should be given with caution in patients receiving Diazepam. 

Reference:

A.S. CLANACHAN and R.J. MARSHALL - POTENTIATION OF THE EFFECTS OF ADENOSINE ON ISOLATED CARDIAC AND SMOOTH MUSCLE BY DIAZEPAM - Volume 71, Issue 2, pages 459–466, February 1980, Br. J. Pharmac. (1980), 71, 459-466