dunno about this medication advice

i'd be looking at the mechanical side of things & what possy you are in bed

if its happening on the right side.. perhaps sleep on the left 

and look at learning how to maintain oneself through exercise in the prevention of future cramp attacks, repetition stretching exercises.. rotation of the back away from the right would be a good start and would also add flexion of the back too...be best to read up on it.