Gabapentin
Gabapentin binds the alpha-2-delta subunit of voltage-gated calcium channels in the central nervous system, reducing the release of excitatory neurotransmitters; despite the name it does not act directly on GABA receptors. It is used for neuropathic pain and as an add-on treatment in epilepsy.
Food is not a constraint, but antacids containing aluminium or magnesium cut absorption noticeably, so a gap of at least a couple of hours between the two is needed. Drowsiness, unsteadiness and slowed reactions are common, particularly at the start and after any increase, and they combine with alcohol and other sedatives — driving and machinery need care until the effect is known. Elimination is entirely renal, so creatinine and eGFR guide how much is appropriate. Stopping abruptly can provoke withdrawal symptoms or seizures.
Persistent or worsening sedation, confusion, marked unsteadiness or slurred speech — especially where kidney function may have changed — should be assessed by a doctor. Breathing that becomes slow or shallow, or a rash, needs urgent attention.
Reference information, not medical advice. Discuss any change with your doctor.