Gabapentin is an anticonvulsant. It helps prevent certain types of seizures in people who have epilepsy. It’s not a cure for epilepsy — the drug will only work to control your seizures as long as you keep taking it. Gabapentin is also used in adults to relieve nerve pain after a case of shingles.
Gabapentin is fairly safe when you use it correctly. It does come with some possible side effects, though. People who misuse this drug are at risk of additional side effects, as well.
Common side effects
The more common side effects of gabapentin include:
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- abnormal eye movements that are continuous, uncontrolled, back-and-forth, or rolling
- clumsiness or unsteadiness
- constipation
- diarrhea
- difficulty speaking
- drowsiness or tiredness
- dry mouth
- nausea
- vomiting
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Serious side effects
Gabapentin may also cause some serious side effects. These side effects are uncommon. However, they may be more common in people who have psychiatric disorders. Very few people taking gabapentin have serious problems.
Call a doctor or call 111 straight away if you have a serious side effect, including:
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- 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)
- violent behavior, aggressiveness, or anger
- anxiousness or restlessness
- anxiety that is new or worse
- depression that is new or worse
- irritability that is new or worse
- mania
- panic attacks
- suicidal thoughts or behavior
- insomnia (trouble sleeping)
Call your doctor right away if you have any of these symptoms.
Allergic Reaction
Gabapentin may cause serious or life-threatening allergic reactions. However, this is very rare. These symptoms may be the first signs of a serious reaction:
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- skin rash
- hives
- difficulty breathing
- fever
- gland swelling that does not go away
- swelling of your face, lip, throat, or tongue
- yellowing of your skin or the whites of your eyes
- unusual bruising or bleeding
- severe tiredness or weakness
- unexpected muscle pain
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Call your doctor right away if you have any of these symptoms. If you think your symptoms are life-threatening, call 911.
Side Effects of Misuse
Gabapentin doesn’t produce the same effects of medications that are often misused, such as benzodiazepines and opiates. Still, misuse of gabapentin has been reported. There have been rare cases of withdrawal. The withdrawal symptoms include:
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- anxiety
- confusion
- rapid heart rate
- sweating
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These effects occurred only in people who used high doses of gabapentin for an extended period to treat illnesses for which the drug isn’t approved.
Of the people who have misused the drug, most had a history of substance misuse or used gabapentin to help with withdrawal symptoms from other substances. Talk to your doctor if you have a history of drug addiction or misuse. This information can help your doctor decide whether any risk of misuse outweighs the potential benefit of using gabapentin.
Serious Allergic Reaction
In rare cases, it’s possible to have a serious allergic reaction (anaphylaxis) to gabapentin.
Other Side Effects
These are not all the side effects of gabapentin. For a full list, see the leaflet inside your medicines packet.