My doctor gave me 4mg of Diazapam for a 4 hour flight coming up at the end of this week. He gave me 2mg to make sure i didnt have any bad reactions to it.

I am flying with someone who is prescribed Xanax. If the 4mg isnt enough for me on the flight and i start to have a panic attack would it be ok for me to take .25 or .5 mg of my friends xanax?