Generality
Carbamazepine is an active ingredient with anticonvulsant activity .
Approved for the first time by the FDA (Food and Drug Administration) of the United States in 1968, carbamazepine is still used today in the treatment of epileptic seizures, but also in the treatment of trigeminal neuralgia (pain relief) and psychiatric disorders such as manias (antimanic activity).
In order to perform its action, carbamazepine must be taken orally and, at appropriate dosages, it can also be used in children.
From the chemical point of view, carbamazepine is a dibenzoazepine (imminostilbene).
Examples of Specialties Medicinal containing Carbamazepine
- Carbamazepine EG®
- Tegretol®
Therapeutic indications
When is the use of carbamazepine indicated?
The use of carbamazepine is indicated for the treatment of:
- Psychomotor or temporal epilepsy, generalized tonic-clonic seizures, focal crises and mixed forms (adult and pediatric patients);
- Essential trigeminal neuralgias (adult patients);
- States of mania (adult patients).
Please note
Carbamazepine is not effective in treating epileptic forms such as small illness and myoclonic attacks.
Warnings
Warnings and Precautions for the use of Carbamazepine
Before starting treatment with carbamazepine, you must inform your doctor if you are in one or more of the following conditions:
- You suffer from liver and / or renal diseases (including urinary retention);
- You suffer from cardiovascular diseases;
- You are allergic to other antiepileptic drugs, such as phenytoin, primidone or phenobarbital;
- You are being treated with other antiepileptic drugs;
- It is being treated with drugs that reduce blood sodium levels, such as, for example, thiazide diuretics;
- You suffer from hypothyroidism;
- You suffer, or have suffered in the past, from blood disorders;
- You suffer from osteoporosis;
- You have bone marrow damage.
Did you know that ...
Individuals of Chinese, Thai, Japanese, Caucasian, Hispanic origin originating in southern India, of Arab descent or descendants of indigenous American peoples are at high risk of developing severe skin reactions following carbamazepine intake. Therefore, if you belong to any of the aforementioned ethnic groups or if you have descendants within them, you must tell your doctor before starting the carbamazepine treatment.
However, as a precautionary measure, before taking carbamazepine-based medicines, it is always advisable to talk to your doctor about your health conditions and inform them of the possible presence of any type of disorder or illness.
Also, remember that during treatment with carbamazepine, you must immediately inform your doctor if any of the following conditions are true:
- Appearance of severe skin reactions ;
- Occurrence of suicidal thoughts ;
- Onset of symptoms such as tachycardia, nausea or vomiting and difficulty breathing, as it could mean that the dose of carbamazepine administered is excessively high .
Please note
The administration of carbamazepine may alter the ability to drive and / or use machines. Therefore, similar activities should be avoided during therapy with this active ingredient.
Pharmacological Interactions
Interactions between Carbamazepine and Other Drugs
Carbamazepine can give rise to numerous drug interactions, influencing the activity of other drugs; as well as many drugs can affect the action of carbamazepine itself. For this reason, you need to tell your doctor if you are taking, or have recently been taken, drugs such as:
- Other antiepileptic drugs;
- Monoamine oxidase inhibitors ( MAOIs );
- Antibiotic drugs, antiviral and antifungal drugs;
- Antihypertensive and diuretic drugs;
- Calcium channel blockers ;
- Antipsychotic drugs;
- Muscle relaxants ;
- Non-steroidal anti-inflammatory drugs ( NSAIDs );
- Corticosteroids ;
- Antidepressants ;
- Antihistamines ;
- Sedative-hypnotic drugs;
- Gastroprotective drugs;
- Anticoagulant drugs;
- Antiemetic drugs;
- Anti- cancer drugs;
- Immunosuppressive drugs;
- Levothyroxine ;
- Statins ;
- Anti-asthmatics ;
- Drugs for the treatment of erectile dysfunction ;
- Oral contraceptives and other drugs based on estrogens and / or progesterone ;
- Drugs for the treatment of acne ( isotretinoin );
- Hypericum (or St. John's wort) and its derivatives.
In any case, before starting carbamazepine therapy, it is necessary to tell the doctor if you are taking - or if you have recently been - drugs or products of any kind, including medicines without a prescription (SOP ), OTC drugs, herbal and herbal products and homeopathic products.
For more information about the interactions between carbamazepine and other drugs, careful reading of the package insert of the medicinal product to be used is recommended.
Taking Carbamazepine with Food and Drinks
The following should not be taken during treatment with carbamazepine:
- Grapefruit juice, as it can increase the effects of carbamazepine;
- Alcoholic, since carbamazepine reduces the tolerability to the ethyl alcohol contained in them.
Side effects
Side effects caused by the intake of carbamazepine
Carbamazepine can cause several side effects, although not all patients manifest them, or manifest them in the same way. In fact, each person responds in a subjective manner to the administration of the active ingredient in question. However, below are some of the main side effects that may occur during treatment with carbamazepine. For more detailed information, we recommend reading the package insert of the medicinal product prescribed by the doctor and which must be used.
Blood disorders
During treatment with carbamazepine, leukopenia, thrombocytopenia, leukocytosis and lymphadenopathy may occur.
Nervous system disorders
Carbamazepine therapy may promote the appearance of:
- Ataxia;
- dizziness;
- Drowsiness;
- Headache;
- Tremors, dystonia and dyskinesias;
- dysgeusia;
- Speech disorders;
- paresthesia;
- Paresis;
- Peripheral neuropathies.
Psychiatric disorders
Psychiatric disorders such as: may occur during treatment with carbamazepine
- Depression;
- Agitation and restlessness;
- Confusional state;
- Aggression;
- Visual and / or auditory hallucinations.
Cardiovascular disorders
During the intake of carbamazepine side effects on the cardiovascular system may arise, such as:
- Cardiac conduction disorders;
- arrhythmias;
- Atrioventricular block with syncope;
- Congestive heart failure;
- Hypertension or hypotension;
- Aggravation of pre-existing coronary heart disease
Gastrointestinal disorders
Oral administration of carbamazepine may cause:
- Nausea and / or vomiting;
- Dry mouth;
- Diarrhea or constipation;
- Abdominal pains;
- In very rare cases, stomatitis, glossitis and pancreatitis.
Ear and labyrinth disorders
Treatment with carbamazepine can cause ear disorders such as:
- Tinnitus;
- hyperacusis;
- Hearing loss;
- Altered tone perception.
Skin and subcutaneous tissue disorders
Carbamazepine therapy may favor the appearance of:
- Urticaria;
- Itch;
- Allergic dermatitis;
- Exfoliative dermatitis;
- Systemic lupus erythematosus;
- Stevens-Johnson syndrome or toxic epidermal necrolysis;
- Erythema multiforme;
- Photosensitivity reactions;
- Changes in skin pigmentation;
- Alopecia or hirsutism.
Other side effects
Other side effects that may occur during treatment with carbamazepine are:
- Allergic reactions - even severe - in sensitive individuals that can manifest with symptoms affecting multiple organs and systems;
- Fatigue;
- Muscle weakness;
- Appetite reduction;
- Water retention;
- Edema;
- Hyponatremia;
- Reduction of blood osmolarity;
- Increased body weight;
- Blurred vision, double vision and nystagmus;
- Sexual dysfunctions;
- Erectile dysfunction and decreased sperm count and / or motility;
- Porphyria;
- Alterations in bone metabolism;
- Liver disease;
- Changes in renal function;
- Increased blood levels of gamma-GT, cholesterol, HDL and triglycerides;
- Decreased blood levels of thyroxine and increased levels of thyroid stimulating hormone.
Overdose
In the event of an overdose of carbamazepine, multiple symptoms can occur, some of which are also very serious. Among these, we mention a few:
- Depression of the central nervous system;
- Disorientation, dysarthria, psychomotor disorders and convulsions;
- Respiratory depression;
- Tachycardia;
- Hypotension or hypertension;
- Syncope;
- He retched;
- Urinary retention, oliguria and anuria.
Treatment of overdose involves hospitalization of the patient. Although there are no specific antidotes, it is still possible to perform gastric lavage and administer activated charcoal . If necessary, coal casting is also possible. The patient will also receive all the necessary support treatments .
Given the seriousness of the symptomatology, in case of assumption - ascertained or presumed - of excessive doses of carbamazepine, it is necessary to immediately contact the sanitary assistance ( call 118 ) or go to the nearest emergency room bringing with him the packaging of the medicine taken.
Action mechanism
How does Carbamazepine work?
Carbamazepine is used in therapy to treat disorders completely different from one another. This is possible because this active principle is capable of performing different functions centrally.
Antiepileptic activity
The antiepileptic activity of carbamazepine appears to be attributable to the blocking of voltage-dependent sodium channels performed by interaction with the alpha subunit of the same. Thanks to this block we are witnessing the inhibition of repeated neuronal discharges and the reduction of synaptic propagation of the excitatory impulses . In addition to this, carbamazepine is also able to stabilize hyperexcited nerve membranes and to reduce the release of glutamate (one of the excitatory neurotransmitters present in the central nervous system).
Antimanic activity
The ability of carbamazepine to counteract mania episodes is very likely due to the inhibition of dopamine and noradrenaline turnover that the active ingredient in question is able to exercise.
Pain-relieving activity
The mechanism of action by which carbamazepine manages to counteract trigeminal neuralgia, unfortunately, is not yet known. Nevertheless, its effectiveness is proven by numerous studies and by the same clinical practice.
Method of use and Posology
How to take Carbamazepine
As mentioned, in order to carry out its therapeutic action, carbamazepine must be administered orally . For this reason, the drug is formulated in tablets or syrup (the latter pharmaceutical form is indicated for children).
The tablets should be swallowed whole with a little water, while the syrup should be drunk as it is.
Usually, carbamazepine can be taken either before or after meals, however, it is advised to always follow the instructions given by your doctor.
The dosage of carbamazepine must be established by the aforementioned health figure for each patient according to various factors, such as: age, body weight, a disorder that must be treated and the response of the same patient to therapy. In any case, the doses normally used will be reported below which, however, may be modified by the doctor if he deems it necessary.
Treatment of epileptic crises
Adults
In the treatment of epilepsy, the dose of carbamazepine usually used in adults at the start of treatment is 100-200 mg once or twice a day. After that, the doctor can increase the amount of active ingredient administered until the optimal maintenance dose is reached for each patient. However, this dose should not exceed 400 mg carbamazepine two or three times a day.
children
To treat epilepsy, carbamazepine can also be given to children. Generally, syrup is used. The usual dosages will be summarized below.
- Initial carbamazepine dose:
- Children under 4 years of age: 20-60 mg a day; subsequently the dose is increased by 20-60 mg every two days until the ideal maintenance dose is reached.
- Children over 4 years of age: 100 mg a day; later, this dose is increased by 100 mg per week until the ideal maintenance dose is reached.
- Carbamazepine maintenance dose:
- Children under 1 year of age: 100-200 mg per day.
- Children between 1 and 5 years: 200-400 mg per day to be divided into 2-3 administrations.
- Children aged between 6 and 10 years: 400-600 mg per day to be divided into 2-3 administrations.
- Children and adolescents aged 11 to 15 years: 600-1000 mg per day to be divided into 2-3 administrations.
- Adolescents over 15 years of age: 800-1200 mg per day to be divided into 2-3 administrations.
Trigeminal Neuralgia Treatment
In adult patients, carbamazepine can also be used to treat trigeminal neuralgia. In this case, the usual starting dose is 200-400 mg a day. The dosage can then be gradually increased until the pain disappears. In most cases, resolution of the pain stimulus is achieved when the dose of 200 mg carbamazepine is reached three or four times a day.
Subsequently, the doctor will proceed to gradually reduce the amount of active ingredient administered until the minimum effective maintenance dose is reached.
Treatment of Manias
Finally, in adult patients, carbamazepine can also be used to treat mania, a particular type of psychiatric disorder. The dose of active ingredient usually used in these cases is 400-600 mg to be taken in two or three divided doses throughout the day.
Elderly Patients and Sensitive Patients
In elderly patients and particularly sensitive patients, the doctor may decide to reduce the doses of carbamazepine usually administered.
Pregnancy and breastfeeding
Can Carbamazepine be taken during pregnancy and during breastfeeding?
Carbamazepine intake during pregnancy can have negative effects on the health of the fetus, as it exposes it to a high risk of developing malformations such as cleft lip or heart and vascular system malformations. Therefore, the use of the active ingredient is generally contraindicated during gestation, except in the case where the doctor does not consider it absolutely necessary to safeguard the life of the woman.
Since carbamazepine is excreted in breast milk, breastfeeding mothers must necessarily inform their doctor of their condition before starting treatment with the active substance in question. However, even in this case, the use of carbamazepine is generally contraindicated, unless the doctor considers it absolutely necessary.
Please note
Carbamazepine may reduce the effectiveness of oral contraceptives . Therefore, during treatment with this active ingredient, it is advisable to use alternative methods of contraception (for example, prophylactic). If in doubt, contact your doctor or your gynecologist.
Contraindications
When Carbamazepine Should Not Be Used
Carbamazepine should NOT be used under one or more of the following conditions:
- Known hypersensitivity to carbamazepine itself or to any of the excipients contained in the medicinal product to be used;
- Known hypersensitivity to other medicinal products having a chemical structure similar to that of carbamazepine (such as, for example, tricyclic antidepressants);
- Presence of atrioventricular block;
- Presence of bone marrow depression or impaired production of blood cells;
- Presence of hepatic porphyrias;
- Therapy with monoamine oxidase inhibitors (MAOIs);
- Pregnancy and breastfeeding.
