Gabapentin, originally developed as an anticonvulsant for epilepsy and FDA-approved to treat postherpetic neuralgia (nerve pain following shingles), is widely used off-label for a variety of conditions.
- Gabapentin is sometimes used as a preventative treatment for migraines. While it’s not a first-line treatment, it can help reduce the frequency of migraines in some patients who are resistant to other therapies.
- Cluster Headaches: There is some limited off-label use for cluster headaches, though gabapentin is not highly effective compared to other treatments and is generally used if standard treatments are not suitable or effective.
Get emergency medical help if you have signs of an allergic reaction to gabapentin: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Seek medical treatment if you have a skin rash with symptoms of a serious allergic reaction that can affect other parts of your body, including: fever, dark urine, blood in your urine, swollen glands, sore throat, extreme weakness or tiredness, unusual bruising or bleeding, muscle pain, or jaundice (yellowing of the skin or eyes).
Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, depression, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.
Call your doctor at once if you have:
- increased seizures;
- severe weakness or tiredness;
- upper stomach pain;
- chest pain, new or worsening cough with fever, trouble breathing;
- severe tingling or numbness;
- rapid back and forth movement of your eyes;
- kidney problems–little or no urination, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath; or
- severe skin reaction–fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Some side effects are more likely in children taking gabapentin. Contact your doctor if the child taking this medication has any of the following side effects:
- changes in behavior;
- memory problems;
- trouble concentrating; or
- acting restless, hostile, or aggressive.
Common gabapentin side effects may include:
- dizziness, drowsiness; or
- headache.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Like all medicines, gabapentin can cause side effects, although not everyone gets them.
Common side effects
These common side effects of gabapentin may happen in more than 1 in 100 people. They’re usually mild and go away by themselves.
There are things you can do to help cope with them:Feeling sleepy, tired or dizzy
- Feeling sick (nausea)
- Being sick (vomiting)
- Diarrhoea
- Mood changes
- Swollen arms and legs
- Blurred vision
- Dry mouth
- Difficulty getting an erection
- Weight gain
- Memory problems
- Headaches
- Getting more infections than usual
Gabapentin Serious side effects
Very few people taking gabapentin have serious problems.
Call a doctor or call 111 straight away if you have a serious side effect, including:
- thoughts of harming or killing yourself – a small number of people taking gabapentin have had suicidal thoughts, which can happen after only a week of treatment
- a high temperature, swollen glands that do not go away, your eyes or skin turn yellow (this may be less obvious on brown or black skin), unusual bruises or bleeding, severe tiredness or weakness, unexpected muscle pain or weakness, with or without a rash – these may be symptoms of a serious reaction
- long-lasting stomach pain, feeling sick or being sick – these may be warning signs of an inflamed pancreas
- muscle pain or weakness and you’re having dialysis treatment because of kidney failure
- seeing things that are not there (hallucinations)
Serious allergic reaction
In rare cases, it’s possible to have a serious allergic reaction (anaphylaxis) to gabapentin.
Immediate action required:Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you’re breathing very fast or struggling to breathe (you may become very wheezy or feel like you’re choking or gasping for air)
- your throat feels tight or you’re struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who’s unwell may also have a rash that’s swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Information:
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Long-term side effects
Some people can become addicted to gabapentin. If this happens, you’ll have withdrawal symptoms after you stop taking the medicine.
When you stop taking gabapentin, you’ll need to reduce your dose gradually to avoid withdrawal symptoms. Do not stop taking gabapentin without talking to your doctor.
Talk to your doctor if you’re concerned about becoming physically dependent on gabapentin.
Other side effects
These are not all the side effects of gabapentin. For a full list, see the leaflet inside your medicines packet.