together sometimes and I have not had any problems. However, since magnesium may decrease the amount of gabapentin your body absorbs it is suggested magnesium be taken 2 hours before gabapentin.

The Mayo Clinic website listed only these specific forms of magnesium in relation to gabapentin absorption:

Magnesium Carbonate
Magnesium Hydroxide
Magnesium Oxide
Magnesium Trisilicate

So, if you're worried you could take another chelate like glycinate, citrate, gluconate, malate, taurate etc.