Gabapentin and alcohol are not an automatic "never" for most people, but both slow the brain the same way, so combining them can make you seriously drowsy, dizzy, and — in higher-risk people — affect your breathing; go easy and talk to your doctor first.
A "caution" verdict fits what the authoritative sources say. Alcohol and gabapentin are both central-nervous-system depressants, so their sedating effects stack. MedlinePlus states plainly that "alcohol can add to the drowsiness caused by this medication," and the practical result is more drowsiness, dizziness, slowed thinking, and loss of coordination than either causes alone. The sources genuinely differ in tone, and honesty means showing that: the UK's NHS is permissive — "Yes, you can drink alcohol while taking gabapentin, but it may make you feel sleepy or tired" — while the US FDA-approved Medication Guide is more cautious, telling patients "Do not drink alcohol... while taking NEURONTIN without first talking with your healthcare provider." The FDA guide also warns that serious breathing problems can occur when gabapentin is taken with other medicines that cause severe sleepiness or decreased awareness, or by someone who already has breathing problems — which is what turns "a bit sleepy" into a real safety issue for some people. That is why the answer is caution / ask your doctor, not a blanket "safe" and not a blanket "never."
Timing from the sources: the NHS advises that "during the first few days of taking gabapentin, it might be best to stop drinking alcohol until you see how the medicine affects you," and the same applies whenever your dose is increased — there is no stated "wait X hours after a dose" separation window, so don't assume one. Be especially careful (talk to your prescriber before drinking) if you also take opioids, anti-anxiety or benzodiazepine medicines, sleeping pills, or any other medicine that makes you sleepy or dizzy, or if you already have a breathing or lung condition — these raise the serious-breathing risk the FDA warns about. Do not drive, cycle, or use machinery until you know how the combination affects you. Get emergency help for red-flag signs of over-sedation or breathing trouble: very slow, shallow, or paused breathing; blue-tinged lips; being extremely sleepy or hard to wake; confusion or slurred speech; or fainting. Call your own clinician (non-emergency) if you regularly want to drink while on gabapentin, if drowsiness or dizziness is interfering with daily life, or before drinking at all if any higher-risk factor above applies to you.
This is general reference, not medical advice, and not a guarantee of safety. Interactions depend on your doses, health conditions, and other medicines. Always confirm with your pharmacist or doctor before combining products, and follow the dosing on each label.