Gabapentin – composition, action, indications, dosage, side effects

Gabapentin is a drug used to treat epilepsy, it is also used in the treatment of neuropathic pain, including diabetic polyneuropathy and post-herpetic neuralgia. It is used as the sole drug in these diseases or as a component of combined treatment depending on the types of disease.

Gabapentin – characteristics

Gabapentin is a medicine that is used to treat epilepsy and peripheral neuropathic pain (long lasting pain caused by damage to the nerves).

The active substance of Gabapentin is gabapentin. Gabapentin is available in the following forms:

1. Gabapentin 100 mg capsules, hard
2. Gabapentin 300 mg capsules, hard
3. Gabapentin 400 mg capsules, hard.

Gabapentin is indicated as an adjunct to the treatment of partial seizures, with or without secondary generalized seizures, in adults and children 6 years of age and older. Gabapentin is indicated as monotherapy for partial onset seizures with or without secondary generalized seizures in adults and adolescents 12 years of age and older.

Gabapentin is indicated for the treatment of peripheral neuropathic pain such as painful diabetic neuropathy and post-herpetic neuralgia in adults.

Read: Alcoholic epilepsy – causes, symptoms, treatment

Gabapentin – mechanism of action

Gabapentin penetrates rapidly into the brain and prevents seizures in many animal models of epilepsy. Gabapentin has no affinity for the GABAA or GABAB receptor and does not alter GABA metabolism. It does not bind to receptors for other neurotransmitters in the brain and does not interact with sodium channels.

Gabapentin has a high affinity for the alpha 2 delta (.2) subunit, which is potential dependent calcium channels. Binding to the .2 subunit has been suggested. may contribute to the anticonvulsant activity of gabapentin in animals. The results of an extensive set of studies do not suggest any binding sites for this medicinal product other than the .2 .. subunit.

See: Will a blood test help people with epilepsy?

Gabapentin – dosage

The dosage of Gabapentin depends on the age and the disease type. The drug can be taken regardless of meals. Gabapentin should be swallowed whole with a sufficient amount of fluid (e.g. a glass of water).

In epilepsy, the dose of Gabapentin is as follows:

1. treatment can be started at a dose of 300 mg three times a day on the first day of treatment. Thereafter, depending on individual response and patient tolerance to the medicinal product, the dose may be increased by 300 mg / day every 2-3 days, up to a maximum dose of 3600 mg / day. In some patients, a slower dose increment of gabapentin may be indicated;
2. the minimum time to reach a dose of 1800 mg / day is 1 week, to reach a dose of 2400 mg / day is a total of two weeks, and to reach a dose of 3600 mg / day is a total of three weeks. Doses up to 4800 mg / day have been well tolerated in long-term, open label clinical trials. The total daily dose should be divided into three single doses, the maximum time interval between doses should not be longer than 12 hours to prevent breakthrough attacks.

When dosing Gabapentin in children over six years of age, the starting dose should be 10 to 15 mg / kg / day. An effective dose is reached by gradually increasing the dose over a period of about three days. The effective dose of gabapentin in children 6 years of age and older is 25 to 35 mg / kg / day. Doses up to 50 mg / kg / day have been well tolerated in a long-term clinical study. The total daily dose should be divided into three single doses, the maximum time interval between doses should not exceed 12 hours.

Dosage of Gabapentin in the treatment of peripheral neuropathic pain:

1. treatment can be started with a dose of 300 mg to 900 mg. Alternatively, treatment can be started with the administration of 900 mg / day in three equal divided doses;
2. depending on the patient’s individual response to the medicinal product and tolerability – the dose may be increased by 300 mg / day every 2-3 days, up to a maximum dose of 3600 mg / day;
3. in some patients, a slower dose titration of gabapentin may be indicated. The minimum time to reach a dose of 1800 mg / day is one week, to reach a dose of 2400 mg / day is a total of two weeks, and to reach a dose of 3600 mg / day is a total of three weeks.

Read: Doctors: Chopin suffered from temporal epilepsy

Gabapentin – dosing in special groups

In people in poor general condition, i.e. with low body weight, in patients after transplantation, etc., the dosage should be increased more slowly – using lower doses or extending the interval between subsequent increases in the daily dose.

Elderly patients may require dose adjustment due to declining renal function with age, somnolence, peripheral edema, asthenia may be more common in the elderly.

Your doctor may also prescribe a different dosing schedule and / or dose for people with renal insufficiency or those treated with hemodialysis. For anuric patients undergoing hemodialysis who have never received gabapentin before, a loading dose of 300 to 400 mg is recommended, followed by 200 to 300 mg of gabapentin after every 4 hours of hemodialysis. Gabapentin should not be administered in the days between hemodialysis sessions.

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Gabapentin – contraindications and precautions

Talk to your doctor or pharmacist before taking Gabapentin:

1. as already mentioned above, in the case of kidney problems, your doctor may prescribe a different dosing schedule,
2. if you are being treated with hemodialysis (to remove waste products due to kidney failure), tell your doctor if you experience muscle pain and / or weakness,
3. If you develop symptoms such as persistent stomach pain, feeling sick, vomiting, contact your doctor immediately as these may be symptoms of acute pancreatitis.
4. if the patient has diseases of the nervous system, respiratory system or is over 65; your doctor may prescribe a different dosage.

There have been reports of abuse and dependence in association with the use of gabapentin in the post-marketing setting. If the patient has a history of drug abuse or drug addiction, please tell your doctor.

A small number of people being treated with anti-epileptics such as gabapentin have had thoughts of harming or killing themselves.

The main contraindication to taking the drug Gabapentin is an allergy to the active substance or any of the other ingredients of this drug. It is also worth knowing that gabapentin can cause anaphylaxis. Signs and symptoms of reported cases included difficulty in breathing, swelling of the lips, throat, and tongue, and hypotension requiring emergency treatment. Patients should be advised to discontinue gabapentin and seek immediate medical attention if signs or symptoms of anaphylaxis occur.

Gabapentin – interactions with other drugs

Tell the doctor or pharmacist about all the medicines the patient is taking, recently, and about the medicines the patient is going to take. In particular, tell your doctor (or pharmacist) about all drugs that have been recently or are currently used to treat seizures, sleep disorders, depression, anxiety disorders or any other neurological or mental disorders.

Medicines containing opioids, such as morphine

If you are taking medicines containing opioids (such as morphine), tell your doctor or pharmacist as opioids may increase the effect of Gabapentin.

In addition, simultaneous use of Gabapentin and opioids may cause symptoms such as sleepiness and / or shortness of breath.

Antacids for indigestion

If you take Gabapentin together with antacids containing aluminum and magnesium, absorption of Gabapentin from the stomach may be limited. It is therefore recommended that Gabapentin is taken at the earliest two hours after taking an antacid.

Lek Gabapentin:

1. it does not interact with other antiepileptic drugs or with oral contraceptives,
2. may affect the results of some laboratory tests, if you have a urine test, tell your doctor or hospital about your current medications.

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Gabapentin – side effects

Due to possible serious health consequences, contact your doctor immediately if you experience any of the following symptoms after taking this medicine:

1. severe skin reactions requiring immediate medical attention, swelling around the mouth and face, skin rash and redness and / or loss of hair (these may be signs of a serious allergic reaction)
2. persistent stomach pain, feeling sick and being sick as these may be symptoms of acute pancreatitis
3. breathing difficulties which, especially if they are severe, may require immediate and intensive medical care to restore normal breathing.

Gabapentin can cause serious or life-threatening allergic reactions that can affect the skin or other parts of the body, for example the liver or blood cells. A rash may appear with this reaction. Such a reaction may require you to go to hospital or stop taking Gabapentin. Contact your doctor immediately if you experience any of the following symptoms:

1. skin rash
2. hives
3. fever,
4. persistent enlargement of the lymph nodes,
5. swelling of the lips and tongue
6. yellowing of the skin or whites of the eyes
7. unusual bruising or bleeding
8. severe tiredness or weakness
9. unexpected muscle pain
10. frequent infections.

These symptoms could be the first sign of a serious illness. Your doctor should examine you and decide whether to continue taking Gabapentin.

Very common side effects (may affect more than 1 in 10 people):

1. viral infections,
2. drowsiness, dizziness, lack of coordination
3. feeling tired, fever.

Common side effects (may affect up to 1 in 10 people):

1. pneumonia, respiratory infections, urinary tract infections, inflammation of the ear or other infections
2. reduction in the number of white blood cells
3. anorexia, increased appetite
4. anger towards others, confusion, mood changes, depression, anxiety, nervousness, abnormal thinking.

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Gabapentin – effects on the ability to drive and use machines

Gabapentin has minor or moderate influence on the ability to drive and use machines. Gabapentin acts on the central nervous system and may cause drowsiness, dizziness or other related symptoms. Even if their severity is mild or moderate, the undesirable effects mentioned may be potentially dangerous in patients who drive vehicles or operate machines. This is especially important when starting treatment or increasing the dose.

Gabapentin – overdose

Acute, life-threatening toxicity has not been observed with gabapentin overdoses of up to 49 g. Symptoms of overdose included dizziness, diplopia, slurred speech, lethargy, loss of consciousness, lethargy and mild diarrhea.

All subjects recovered fully with supportive care. Decreasing gabapentin absorption at higher doses may limit the amount of medicinal product absorbed after overdose and thus minimize its toxic effects.

Overdosage of gabapentin, especially in combination with other antidepressant drugs, may result in coma.

Although gabapentin can be removed from the body by hemodialysis, based on experience to date, it is not usually necessary. In people with severe renal insufficiency, hemodialysis may be indicated.