Gabapentin

Sounds like 'gab-a-pen-tin'

Gabapentin is used to treat some types of nerve pain and epilepsy and prevent migraine headaches. Find out how to take it safely and possible side effects. Gabapentin is also called Neurontin or Nupentin.

Type of medicine Also called
  • Pain medication 
  • Anticonvulsant (to treat epilepsy)
  • Neurontin®
  • Nupentin®
  • Apo-Gabapentin®

What is gabapentin?

Gabapentin works by changing the way that nerves send messages to your brain. It has many uses, including:

  • to relieve nerve pain (also called neuropathy) – this occurs when damage or changes to your nerves, through injury or disease such as diabetes or shingles, causes them to misfire and send pain signals to your brain
  • to treat epilepsy by preventing some types of seizures
  • to prevent attacks of migraine if other medicines are not suitable. 

In New Zealand, gabapentin is available as capsules. 

Dose

  • The dose of gabapentin is different for different people. 
  • Your doctor will usually start you on a low dose and increase the dose over a few days. This allows your body to get used to the medicine and reduces the chances of side effects.
  • Most people take 3 doses a day once they are on a regular dose. 
  • Always take your gabapentin exactly as your doctor has told you.
  • The pharmacy label on your medicine will tell you how much gabapentin to take, how often to take it and any special instructions.  
My dose is:

Date Morning Lunch Night
       
       
       
       
Notes:



How to take gabapentin

  • Timing: Take gabapentin at the same times each day. You can take gabapentin with or without food. Try taking gabapentin with food if it makes you feel sick (nausea).
  • Swallow the capsules whole, with a glass of water: If you have problems swallowing the capsule, you can open it and mix the contents with apple sauce or orange juice, just before taking it. The capsule contents have an unpleasant taste.
  • Limit or avoid alcohol while taking gabapentin: Taking gabapentin and alcohol can make your more sleepy, drowsy or dizzy and increase your risk of falls.
  • Missed dose: If you forget to take your dose, take it as soon as you remember. But if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.
  • Pain relief is not immediate: If you are taking gabapentin for pain, it will not relieve pain immediately. It may take a few days before you feel less pain.
  • Keep taking gabapentin regularly: If you think gabapentin is not working for you, do not stop taking it suddenly. Stopping treatment suddenly can cause side effects. Talk to your doctor or nurse before stopping. It is usually best to stop gabapentin slowly.

Precautions – before starting gabapentin

  • Do you have kidney problems?
  • Do you have problems with your heart?
  • Do you have diabetes?
  • Have you had any psychotic episodes?
  • Are you pregnant or breastfeeding?
  • Are you taking any other medicines? This includes any medicines you buy without a prescription, such as herbal and complementary medicines and medicines for pain relief.

If so, it’s important that you tell your doctor or pharmacist before you start gabapentin. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Side effects

Like all medicines, gabapentin can cause side effects, although not everyone gets them. Often side effects improve as your body adjusts to the new medicine.

Problems with dizziness and drowsiness

This is quite common when you start taking gabapentin. Up to 1 in 3 people experience dizziness or drowsiness.

  • Be careful when driving or using tools until you know how this medicine affects you.
  • Also be careful when getting up from either lying down or sitting. The loss of balance and dizziness can put you at risk of falls and injuries, especially if you are elderly.
  • Avoid drinking alcohol while you are taking gabapentin. This can make dizziness and drowsiness worse. 

Tell your doctor if these side effects are causing difficulties. You may need a lower dose.

Risk of dependence

Gabapentin can cause feelings of excitement and exaggerated happiness (often described as a high or euphoria). For some people, it can become habit forming. The risk of dependence may be higher if you have a history of misuse of alcohol and recreational drugs and if you are taking gabapentin in combination with certain other medicines.

To avoid gabapentin dependence, do not take higher doses, more frequent doses or for longer than you were prescribed by a doctor. Let your doctor know if you have any history of drug abuse or start to feel any sense of high or desire for your next dose or if you start taking any new medicines for pain relief.

Always keep gabapentin in a safe place away from children, and do not share this medicine with others.

Other side effects

Side effects What should I do?
  • Stomach upset, feeling sick (nausea)
  • Try taking gabapentin with food.
  • Tell your doctor if troublesome.
  • Weight gain 
  • This is quite common in the first few months of starting gabapentin.
  • Most people gain less than 2 kilograms, but up to 15% of people, depending on dose, gain more than 5 kilograms.
  • Follow a healthy diet and exercise regularly.
  • Headache 
  • Dry mouth and throat
  • This may go away with time.
  • Tell your doctor if troublesome.
  • Ankle or leg swelling
  • This is more common in elderly people or if you are taking higher doses.
  • Tell your doctor.
  • Frequent mood changes, anxiety, depression or worsening depression, aggressive tendencies, thoughts of suicide, abnormal behaviours
     
  • Tell your doctor immediately or phone Healthline 0800 611 116.
  • Signs of an allergy such as skin rash, fever, flu-like symptoms, breathing difficulties.
  • Tell your doctor immediately or phone Healthline 0800 611 116.

Interactions

Gabapentin interacts with a number of medications and herbal supplements so check with your doctor or pharmacist before starting gabapentin and before starting any new medicines.

Do not take antacid preparations 2 hours before or after you have taken a dose.

Learn more

Neurontin Medsafe Consumer Information Sheet
Nupentin Medsafe Consumer Information Sheet 
Gabapentin NZ Formulary Patient Information

References

  1. Spotlight on gabapentin and pregabalin for neuropathic pain Medsafe, 2021
  2. Prescribing gabapentin and pregabalin: upcoming subsidy changes BPAC, NZ, 2018
  3. Managing patients with neuropathic pain BPAC, NZ, 2016
  4. Guide for crushing oral medication for residents with swallowing difficulties in residential aged care Waitematā District Health Board, NZ, 2018
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 17 Mar 2021