I have celiac disease and started gabapentin 100mg capsules mfg'd in India; I have severe bloating?

It can cause bloating as noted in the potential side effects. I don't think the Indian company can be of much help because bloating can also be caused by so many other things they'll likely just say they don't know if they respond at all. What is important is if you notice the bloating is only an issue when on the medication - which it increases bloating (already an issue for me) but I wouldn't call it the cause. For you it may be the cause, or it could be exacerbating a pre-existing issue. If the bloating is due to the medication and it is worse than any relief given then it's good to get off sooner versus later as the withdrawal symptoms become worse generally the longer someone has taken the medication. Do expect some unpleasantness while coming off and even for a month or so after fully quitting, though you may not have this experience it's good to be prepared and know what symptoms may occur.

If you're concerned it's only additives in the medication to bind it you may be able to use a compounding pharmacy to avoid any intolerances. A way to check for these types of intolerances is through an MRT blood test - make sure to choose one with not just foods but also chemicals as it will inform you if a color additive to a medication is an issue and possibly just using a different generic or different dose (frequently the colors are different) then you may be able to stay on the medication. It's also a great test period if bloating or abdominal discomfort is a chronic issue. It's a simple blood test and the results are in green, yellow, red to indicate foods that are good for your body (greens), foods you may need to test or eat only in moderation (yellows) and foods to avoid (reds). A nutritionist can help with MRT testing and a diet plan (if they've been MRT certified) or you can order the blood test through an online lab and the results sheet is easy to read and understand.