Gabapentin — NZ Medication Guide | KiwiMeds
✅ Reviewed by a Registered Pharmacist NZ | Last updated: May 2026 | This information is for educational purposes only and does not replace advice from your doctor or pharmacist.
What is Gabapentin?
Gabapentin (brand name Neurontin) is an anticonvulsant (anti-seizure) medicine that is also widely used for nerve pain. It has structural similarity to GABA but does not act directly on GABA receptors — it works via a different mechanism.
What is it used for?
Gabapentin is used to treat epilepsy (as an add-on therapy), neuropathic pain (nerve pain from conditions such as diabetic neuropathy, post-herpetic neuralgia/shingles nerve pain), fibromyalgia, restless legs syndrome, and anxiety (off-label). It is fully funded by Pharmac.
How does it work?
Gabapentin binds to the alpha-2-delta subunit of voltage-gated calcium channels in the nervous system. This reduces the release of excitatory neurotransmitters (glutamate, substance P, noradrenaline), reducing pain signals and abnormal electrical activity in the brain.
How to take it
Gabapentin is taken 2–3 times daily as directed by your doctor. The dose is started low and gradually increased to minimise side effects. Take it at evenly spaced times. Do not stop suddenly — reduce the dose gradually under medical guidance.
Common side effects
Common side effects include dizziness, drowsiness, fatigue, coordination problems (unsteadiness), weight gain, fluid retention (swollen ankles), blurred vision, and memory or concentration difficulties. Side effects are often dose-related and may improve over time.
Serious side effects
Respiratory depression risk when combined with opioids or other sedatives — this combination should be used with extreme caution. Suicidal thoughts can occur with anticonvulsant medicines — seek help if mood worsens. Angioedema (swelling of face, throat) — rare but serious.
Drug interactions
Opioids combined with gabapentin greatly increase the risk of respiratory depression and sedation — use with extreme caution. Antacids (aluminium/magnesium containing) can reduce gabapentin absorption — take gabapentin 2 hours before antacids. Alcohol enhances sedation.
Things to avoid
Avoid alcohol — increases sedation and dizziness. Avoid driving when first starting or increasing the dose. Do not combine with opioids unless under careful specialist supervision. Never stop suddenly.
NZ-specific information
Gabapentin is funded by Pharmac. It is increasingly recognised as having misuse potential — it can cause euphoria at high doses and dependence can develop. New Zealand has become more cautious about gabapentin and pregabalin prescribing due to these concerns. Some areas are moving these medicines to controlled drug status.
Frequently asked questions
Will gabapentin make me drowsy? Drowsiness and dizziness are very common, especially when starting. This often improves with time, but caution with driving and machinery is important. Is gabapentin addictive? Gabapentin can cause physical dependence and has abuse potential, particularly in people with a history of substance use. Use as directed and do not share your medicine.
💬 Always talk to your pharmacist or doctor for advice specific to you.
Related medications
Related: Pregabalin. Condition: Chronic Pain, Epilepsy.
References & Further Information
The following New Zealand and international resources were used to inform this page: