I take both baclofen and gabapentin. I am currently on 100 mg baclofen and 400 mg gabapentin per day, with zero side effects. I was previously on a much higher dose of baclofen, but have tapered down over the years. The baclofen keeps the alcohol cravings at bay, and the gabapentin helps me to stay asleep throughout the night (I used to have horrible early morning insomnia). I have zero side effects from the combo, and have never had any problems with it. I think I added the gabapentin around 8 months ago.
The baclofen is prescribed by a doctor, but I ordered the gabapentin online to escape the headache of trying to negotiate it with the same doctor.