Two weeks ago, Alan was prescribed pills for back pain, which is now getting better. He still has some pills leftover from this prescription. What is the MOST appropriate action for Alan to take concerning these pills?

A. If he has no more back pain, he can use the pills for any other pains.
B. If a friend is also experiencing back pain, he can give his pills to them.
C. If his back pain flares up in a few days, he can still take the pills.
D. If the back pain gets worse, he can take more pills than were prescribed.

The most appropriate action for Alan to take concerning these leftover pills is C. If his back pain flares up in a few days, he can still take the pills. It is not advisable to use the pills for any other pains, give them to a friend, or take more pills than were prescribed without consulting a healthcare professional.