Gabapentin is an antiepileptic also used for neuropathic and postherpetic pain. It is structurally similar to GABA but does not act directly on GABA receptors.
Also known as: neurontin, gabapentino
DailyMed/FDA — Neurontin; EMC-UK — Gabapentin
DailyMed/FDA — Neurontin; EMC-UK
Antiepileptic + antiepileptic: additive effect on tremor and sedation.
Both can cause tremor and sedation as adverse effects. The effect is additive but there is no pharmacokinetic interaction — gabapentin is not metabolised by CYP and valproate does not affect gabapentin renal excretion. Monitor sedation and tremor, especially in the elderly.
Additive effect on tremor and sedation. No significant pharmacokinetic interaction.
Both can cause tremor and sedation. The effect is additive but there is no significant pharmacokinetic interaction.
Sedation, tremor.
Excessive sedation.
Monitor sedation and tremor. Adjust doses if necessary.
DailyMed/FDA; EMC-UK
Two gabapentinoids: additive CNS depression. Do not combine without justification.
Both act on the α2δ subunit of voltage-gated calcium channels. The combination offers no additional therapeutic benefit (same mechanism) and significantly increases the risk of sedation, dizziness, ataxia, and respiratory difficulty. Do not combine two gabapentinoids — choose one based on the indication.
Two gabapentinoids: additive CNS depressant effect without additional therapeutic benefit.
Both act on the α2δ subunit of calcium channels. The combination offers no additional therapeutic benefit and increases risk of sedation, dizziness, and respiratory difficulty.
Sedation, respiratory function.
Respiratory depression.
Do not combine two gabapentinoids. Choose one.
DailyMed/FDA; EMC-UK
Alcohol potentiates gabapentin CNS depression. Increased risk of sedation and respiratory difficulty.
Avoid alcohol.
100% renally excreted. Significant accumulation in renal impairment.
eGFR 30-59: reduce to 200-700 mg 2x/day. eGFR 15-29: 200-700 mg 1x/day. eGFR <15: 100-300 mg/day.
DailyMed/FDA; EMC-UK
Animal studies show skeletal effects. Limited human data. Use only if benefit justifies risk.
Insufficient data. Use only if benefit justifies risk.
Excreted in breast milk. Decision between discontinuing breastfeeding or drug.
Effects on fertility unknown in humans.
DailyMed/FDA — Neurontin; EMC-UK
Clinical and educational support tool. The information does not replace a medical prescription or the opinion of a qualified healthcare professional.
Antiepileptic and neuropathic pain activity via calcium channel modulation.
Binds to the α2δ-1 subunit of voltage-gated calcium channels, reducing Ca²⁺ influx and excitatory neurotransmitter release (glutamate, noradrenaline, substance P).
Saturable absorption. Bioavailability: 60% (300 mg), 35% (1600 mg). Peak: 2-3 h.
Not metabolised. Excreted 100% unchanged renally. No CYP interactions.
5-7 h (normal), up to 13 h in renal impairment.
Medicines from the same therapeutic group (ATC classification) or the same pharmacological class.
