Gabapentin
Updated on All content is checked by medical journalists.Gabapentin is one of the drugs that is used to treat convulsions and various forms of nerve pain. It blocks certain docking points in the body and in this way normalizes the excitation of the nervous system. Gabapentin is excreted unchanged by the kidneys. Common side effects are tiredness and dizziness. Here you can read everything you need to know about gabapentin, its effects and side effects!
This is how gabapentin works
Gabapentin is a drug with anticonvulsant, analgesic, and sedative properties. It belongs to the group of anti-epileptic drugs.
The human nervous system is activated or inhibited by certain messenger substances. Normally, these messenger substances are released according to external circumstances and ensure that the body reacts appropriately to various situations such as injuries, stress or rest.
This controlled equilibrium is disturbed in diseases of the nervous system. A genetic predisposition or injury to the brain can increase the excitement or reduce the inhibition - the brain is overexcitable, so that epileptic seizures can occur.
Long-term irritation of the nerve tracts in the back and in the limbs (peripheral neuropathy) due to severe diabetes or viral diseases of the nervous system (e.g. from herpes viruses) lead to over-excitability of the nerve endings. As a result, these constantly send signals of irritation to the brain, and the patient feels persistent pain. This so-called nerve pain (neuralgia) cannot be treated with normal painkillers.
In order to alleviate the symptoms of epilepsy and peripheral neuropathy, drugs are therefore required that normalize the excitation of the nervous system - such as gabapentin. Its effect is based on the fact that it reduces the transmission of stimuli to the nerve tracts:
On the one hand, the drug prevents the release of activating messenger substances. On the other hand, it indirectly promotes the breakdown of activating messenger substances and thus also lowers their concentration in the nervous system. Less messenger substances then bind to their receptors - states of tension and pain are released.
However, the full effect of the drug will only develop after a certain period of ingestion (about one to two weeks).
Uptake, breakdown and excretion
Gabapentin is rapidly absorbed after oral administration. After about five to seven hours, half of the active ingredient is broken down (half-life).
The active ingredient is excreted unchanged via the kidneys. The dose must therefore be reduced in people with kidney failure.
When is gabapentin used?
The areas of application (indications) of gabapentin are:
- Therapy of focal epileptic seizures (= seizures that affect only a part or a certain region of the brain) with and without secondary generalization (i.e. extension of the initial focal seizure to the whole brain) - gabapentin is either given alone (monotherapy) or in Combination with other drugs (additional therapy)
- Peripheral neuropathic pain, e.g. as a result of diabetes (diabetic polyneuropathy) or a herpes infection (post-therapeutic neuralgia)
This is how gabapentin is used
Gabapentin is mostly used in the form of tablets or capsules. The drug can be taken with or without food, but always with sufficient liquid (preferably with a large glass of water).
The dosage depends on the indication and is usually between 900 and 3600 milligrams per day for adults. The active ingredient is absorbed in the intestine via a special transporter (amino acid transporter). The daily dose should therefore be divided into three individual doses to ensure complete absorption. In order to achieve an even effect, the individual doses should always be taken at the same time interval.
Gabapentin is dosed gradually at the beginning of therapy. This means starting the dose low and gradually increasing it until a sufficient daily dose is reached. This so-called "titration" can take several weeks, depending on individual tolerance. The titration is important because the doctor has to find a dose specially tailored to the patient that is sufficiently effective and has the lowest possible side effects.
Epilepsy usually requires long-term therapy, as it can only be cured in rare cases.
In the case of neuropathic pain, a withdrawal attempt can be attempted after a certain period of treatment. However, not abruptly, but by gradually reducing the dose over at least a week ("tapering").
What are the side effects of gabapentin?
Virus infections, sleepiness (somnolence), tiredness and dizziness occur very frequently (i.e. in more than ten percent of those treated). Frequently (i.e. in one to ten percent of patients) gabapentin causes side effects such as changes in eating behavior, changes in the blood count, behavioral problems (especially in children), cramps, insomnia and high blood pressure (hypertension).
Respiratory diseases, nausea and vomiting, muscle pain, impotence and skin rashes are also possible. Less than one percent of those treated develop water retention in the body tissue (edema).
What should be considered when taking gabapentin?
Interactions
The amount of active ingredient absorbed is reduced by drugs containing aluminum and magnesium to neutralize gastric acid (antacids). Gabapentin should therefore be taken at least two hours after taking such an antacid for it to work.
If you take morphine (strong pain reliever) at the same time, the concentration of gabapentin in the blood may increase. The gabapentin dose may therefore have to be reduced for the duration of the morphine therapy.
Age restriction
Gabapentin is approved in combination with other drugs (add-on therapy) for partial seizures with and without secondary generalization from the age of six years. The approval for monotherapy is valid for patients from the age of twelve.
There are separate dose tables for individual dose adjustments for children and patients with kidney dysfunction.
pregnancy and breast feeding period
Experience with more than 500 pregnancies using gabapentin in the first trimester of pregnancy does not indicate an increased risk of malformations. However, since such a risk cannot be completely ruled out, a strict risk-benefit assessment is always advisable before using the drug.
More suitable alternatives in pregnancy are lamotrigine for the treatment of epilepsy and amitriptyline for the treatment of neuropathic pain. Gabapentin can be given if these active ingredients are out of the question. The dose should be as low as possible and be divided into several individual doses per day.
No side effects have been reported to date in breast-fed children when the mother takes gabapentin. The use of the drug while breastfeeding is acceptable, but the infant should be closely observed.
How to get gabapentin medication
Tablets and capsules with the active ingredient gabapentin require a prescription in Germany, Austria and Switzerland and are only available with a prescription from a doctor in the pharmacy. Oral solutions, for example for swallowing problems in old age, are only available in Germany.
What else you should know about gabapentin
Due to its lower effectiveness, gabapentin is not an antiepileptic of first choice, but is considered a so-called reserve drug. However, it can make sense to combine other anti-epileptic drugs with gabapentin.
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