My husband takes pravachol (pravastatin) his muscles hurt he also takes gabapentin for neuropathy not a diabetic he gets mood seings?

No interaction. There is no interaction between the two drugs. Pravachol (pravastatin) is a "statin" drug. Muscle pain is an adverse effect to be worried about with these drugs. I would call his prescribing doctor asap. The mood swings may be from his muscle pain.
Statin medications. Statin medications (like pravachol) do often cause muscle aches and can contribute to neuropathy. The are very good medicines overall, however, so speak to your doctor about perhaps changing to another one....Which often fixes the problem.