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New search Medicine profile Carbamazepine

Clinical medicine profile

Carbamazepine

Mood Stabilizer [EPC]

POM
Evidence state Source-linked Review date not recorded
Route
See product SmPC
Schedule
POM
ATC
Not assigned
PPB status
registered
Patient advice Check interactions
01 Risk first

Safety essentials

The information most likely to change a prescribing or dispensing decision.

Critical warning

WARNINGS SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE SERIOUS AND SOMETIMES FATAL DERMATOLOGIC REACTIONS, INCLUDING TOXIC EPIDERMAL NECROLYSIS (TEN) AND STEVENS-JOHNSON SYNDROME (SJS), HAVE BEEN REPORTED DURING TREATMENT WITH CARBAMAZEPINE. THESE REACTIONS ARE ESTIMATED TO OCCUR IN 1 TO 6 PER 10,000 NEW USERS IN COUNTRIES WITH MAINLY CAUCASIAN POPULATIONS, BUT THE RISK IN SOME ASIAN COUNTRIES IS ESTIMATED TO BE ABOUT 10 TIMES HIGHER. STUDIES IN PATIENTS OF CHINESE ANCESTRY HAVE FOUND A STRONG ASSOCIATION BETWEEN THE RISK OF DEVELOPING SJS/TEN AND THE PRESENCE OF HLA-B*1502, AN INHERITED ALLELIC VARIANT OF THE HLA-B GENE. HLA-B*1502 IS FOUND ALMOST EXCLUSIVELY IN PATIENTS WITH ANCESTRY ACROSS BROAD AREAS OF ASIA. PATIENTS WITH ANCESTRY IN GENETICALLY AT-RISK POPULATIONS SHOULD BE SCREENED FOR THE PRESENCE OF HLA-B*1502 PRIOR TO INITIATING TREATMENT WITH CARBAMAZEPINE. PATIENTS TESTING POSITIVE FOR THE ALLELE SHOULD NOT BE TREATED WITH CARBAMAZEPINE UNLESS THE BENEFIT CLEARLY OUTWEIGHS THE RISK (SEE WARNINGS AND PRECAUTIONS , LABORATORY TESTS). APLASTIC ANEMIA AND AGRANULOCYTOSIS APLASTIC ANEMIA AND AGRANULOCYTOSIS HAVE BEEN REPORTED IN ASSOCIATION WITH THE USE OF CARBAMAZEPINE. DATA FROM A POPULATION-BASED CASE CONTROL STUDY DEMONSTRATE THAT THE RISK OF DEVELOPING THESE REACTIONS IS 5 TO 8 TIMES GREATER THAN IN THE GENERAL POPULATION. HOWEVER, THE OVERALL RISK OF THESE REACTIONS IN THE UNTREATED GENERAL POPULATION IS LOW, APPROXIMATELY SIX PATIENTS PER ONE MILLION POPULATION PER YEAR FOR AGRANULOCYTOSIS AND TWO PATIENTS PER ONE MILLION POPULATION PER YEAR FOR APLASTIC ANEMIA. ALTHOUGH REPORTS OF TRANSIENT OR PERSISTENT DECREASED PLATELET OR WHITE BLOOD CELL COUNTS ARE NOT UNCOMMON IN ASSOCIATION WITH THE USE OF CARBAMAZEPINE, DATA ARE NOT AVAILABLE TO ESTIMATE ACCURATELY THEIR INCIDENCE OR OUTCOME. HOWEVER, THE VAST MAJORITY OF THE CASES OF LEUKOPENIA HAVE NOT PROGRESSED TO THE MORE SERIOUS CONDITIONS OF APLASTIC ANEMIA OR AGRANULOCYTOSIS. BECAUSE OF THE VERY LOW INCIDENCE OF AGRANULOCYTOSIS AND APLASTIC ANEMIA, THE VAST MAJORITY OF MINOR HEMATOLOGIC CHANGES OBSERVED IN MONITORING OF PATIENTS ON CARBAMAZEPINE ARE UNLIKELY TO SIGNAL THE OCCURRENCE OF EITHER ABNORMALITY. NONETHELESS, COMPLETE PRETREATMENT HEMATOLOGICAL TESTING SHOULD BE OBTAINED AS A BASELINE. IF A PATIENT IN THE COURSE OF TREATMENT EXHIBITS LOW OR DECREASED WHITE BLOOD CELL OR PLATELET COUNTS, THE PATIENT SHOULD BE MONITORED CLOSELY. DISCONTINUATION OF THE DRUG SHOULD BE CONSIDERED IF ANY EVIDENCE OF SIGNIFICANT BONE MARROW DEPRESSION DEVELOPS.

Contraindications

  • CONTRAINDICATIONS Carbamazepine should not be used in patients with a history of previous bone marrow depression, hypersensitivity to the drug, or known sensitivity to any of the tricyclic compounds, such as amitriptyline, desipramine, imipramine, protriptyline, nortriptyline, etc.
  • Likewise, on theoretical grounds its use with monoamine oxidase (MAO) inhibitors is not recommended.
  • Before administration of carbamazepine, MAO inhibitors should be discontinued for a minimum of 14 days, or longer if the clinical situation permits.
  • Coadministration of carbamazepine and nefazodone may result in insufficient plasma concentrations of nefazodone and its active metabolite to achieve a therapeutic effect.
  • Coadministration of carbamazepine with nefazodone is contraindicated.

Precautions

  • WARNINGS Serious Dermatologic Reactions Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS), have been reported with carbamazepine treatment.
  • The risk of these events is estimated to be about 1 to 6 per 10,000 new users in countries with mainly Caucasian populations.
  • However, the risk in some Asian countries is estimated to be about 10 times higher.
  • Carbamazepine should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related.
  • If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed and alternative therapy should be considered.
  • SJS/TEN and HLA-B*1502 Allele Retrospective case-control studies have found that in patients of Chinese ancestry there is a strong association between the risk of developing SJS/TEN with carbamazepine treatment and the presence of an inherited variant of the HLA-B gene, HLA-B*1502.
  • The occurrence of higher rates of these reactions in countries with higher frequencies of this allele suggests that the risk may be increased in allele-positive individuals of any ethnicity.
  • Across Asian populations, notable variation exists in the prevalence of HLA-B*1502.
  • Greater than 15% of the population is reported positive in Hong Kong, Thailand, Malaysia, and parts of the Philippines, compared to about 10% in Taiwan and 4% in North China.
  • South Asians, including Indians, appear to have intermediate prevalence of HLA-B*1502, averaging 2% to 4%, but higher in some groups.
  • HLA-B*1502 is present in less than 1% of the population in Japan and Korea.
  • HLA-B*1502 is largely absent in individuals not of Asian origin (e.g., Caucasians, African-Americans, Hispanics, and Native Americans).
02 Point of care

Dosing matrix

Population and organ-function guidance, shown together for faster comparison.

Adult

DOSAGE AND ADMINISTRATION (SEE TABLE BELOW) Carbamazepine suspension in combination with liquid chlorpromazine or thioridazine results in precipitate formation, and, in the case of chlorpromazine, there has been a report of patient passing an orange rubbery precipitate in the stool following coadministration of the two drugs (see PRECAUTIONS, Drug Interactions). Because the extent to which this occurs with other liquid medications is not known, Carbamazepine suspension should not be administered simultaneously with other liquid medications or diluents. Monitoring of blood levels has increased the efficacy and safety of anticonvulsants (see PRECAUTIONS, Laboratory Tests). Dosage should be adjusted to the needs of the individual patient. A low initial daily dosage with a gradual increase is advised. As soon as adequate control is achieved, the dosage may be reduced very gradually to the minimum effective level. Medication should be taken with meals. Since a given dose of Carbamazepine suspension will produce higher peak levels than the same dose given as the tablet, it is recommended to start with low doses (children 6 to 12 years: ½ teaspoon four times a day and to increase slowly to avoid unwanted side effects. Conversion of patients from oral Carbamazepine tablets to Carbamazepine suspension: Patients should be converted by administering the same number of mg per day in smaller, more frequent doses (i.e., twice a day tablets to three times a day suspension). Tegretol-XR is an extended-release formulation for twice a day administration. When converting patients from Carbamazepine conventional tablets to Tegretol-XR, the same total daily mg dose of Tegretol-XR should be administered. Tegretol-XR tablets must be swallowed whole and never crushed or chewed. Tegretol-XR tablets should be inspected for chips or cracks. Damaged tablets, or tablets without a release portal, should not be consumed. Tegretol-XR tablet coating is not absorbed and is excreted in the feces; these coatings may be noticeable in the stool. Epilepsy (SEE INDICATIONS AND USAGE) Adults and children over 12 years of age-Initial : Either 200 mg twice a day for tablets and XR tablets, or 1 teaspoon four times a day for suspension (400 mg/day). Increase at weekly intervals by adding up to 200 mg/day using a twice a day regimen of Tegretol-XR or a three times a day or four times a day regimen of the other formulations until the optimal response is obtained. Dosage generally should not exceed 1000 mg daily in children 12 to 15 years of age, and 1200 mg daily in patients above 15 years of age. Doses up to 1600 mg daily have been used in adults in rare instances. Maintenance : Adjust dosage to the minimum effective level, usually 800 to 1200 mg daily. Children 6 to 12 years of age-Initial : Either 100 mg twice a day for tablets or XR tablets, or ½ teaspoon four times a day for suspension (200 mg/day). Increase at weekly intervals by adding up to 100 mg/day using a twice a day regimen of Tegretol-XR or a three times a day or four times a day regimen of the other formulations until the optimal response is obtained.. Dosage generally should not exceed 1000 mg daily. Maintenance : Adjust dosage to the minimum effective level, usually 400 to 800 mg daily. Children under 6 years of age-Initial : 10 to 20 mg/kg/day twice a day or three times a day as tablets, or four times a day as suspension . Increase weekly to achieve optimal clinical response administered three times a day or four times a day. Maintenance : Ordinarily, optimal clinical response is achieved at daily doses below 35 mg/kg. If satisfactory clinical response has not been achieved, plasma levels should be measured to determine whether or not they are in the therapeutic range. No recommendation regarding the safety of carbamazepine for use at doses above 35 mg/kg/24 hours can be made. Combination Therapy : Carbamazepine may be used alone or with other anticonvulsants. When added to existing anticonvulsant therapy, the drug should be added gradually while the other anticonvulsants are maintained or gradually decreased, except phenytoin, which may have to be increased (see PRECAUTIONS, Drug Interactions, and Pregnancy). Trigeminal Neuralgia (SEE INDICATIONS AND USAGE) Initial : On the first day, either 100 mg twice a day for tablets or XR tablets or ½ teaspoon four times a day for suspension, for a total daily dose of 200 mg. This daily dose may be increased by up to 200 mg/day using increments of 100 mg every 12 hours for tablets or XR tablets, or 50 mg (½ teaspoon) four times a day for suspension, only as needed to achieve freedom from pain. Do not exceed 1200 mg daily. Maintenance : Control of pain can be maintained in most patients with 400 to 800 mg daily. However, some patients may be maintained on as little as 200 mg daily, while others may require as much as 1200 mg daily. At least once every 3 months throughout the treatment period, attempts should be made to reduce the dose to the minimum effective level or even to discontinue the drug. Dosage Information Initial Dose Subsequent Dose MaximumDaily Dose Indication Tablet* XR † Suspension Tablet* XR † Suspension Tablet* XR † Suspension Epilepsy Under 6 yr 10-20 mg/kg/day twice a day or 3 times of day 10-20 mg/kg/day 4 times a day Increase weekly to achieve optimal clinical response, 3 times a day or 4 times a day Increase weekly to achieve optimal clinical response, 3 times a day or 4 times a day 35mg/kg/24hr (see Dosage and Administration section above) 35 mg/kg/24 hr (see Dosage and Administration section above) 6-12 yr 100 mg twice a day (200 mg/day) 100 mg twice a day (200 mg/day) ½ tsp 4 times a day (200 mg/day) Add up to 100 mg/day at weekly intervals 3 times a day or 4 times a day Add 100 mg/day at weekly intervals, twice a day Add up to 1 tsp (100 mg)/day at weekly intervals, 3 times a day or 4 times a day 1000mg/24 hr Over 12 yr 200 mg twice a day(400 mg/day) 200 mg twice a day (400 mg/day) 1 tsp 4 times a day (400 mg/day) Add up to 200 mg/day at weekly intervals, 3 times a day or 4 times a day Add up to 200 mg/day at weekly intervals, twice a day Add up to 2 tsp (200 mg)/day at weekly intervals, 3 times a day or 4 times a day 1000 mg/24 hr (12-15 yr) 1200 mg/24 hr (>15 yr) 1600 mg/24 hr (adults, in rare instances) Trigeminal Neuralgia 100 mg twice a day(200 mg/day) 100 mg twice a day (200 mg/day) ½ tsp 4 times a day (200 mg/day) Add up to 200 mg/day in increments of 100 mg every 12 hr Add up to 200 mg/day in increments of 100 mg every 12 hr Add up to 2 tsp (200 mg)/day in increments of 50 mg (½ tsp) 4 times a day 1200mg/24 hr * Tablet = conventional tablets † XR = Tegretol-XR extended-release tablets

Paediatric

See label paediatric section if present; otherwise use paediatric formulary — do not extrapolate adult doses.

Renal

Review renal impairment dosing; many agents need CrCl/eGFR adjustment.

  • CrCl 0–120: Confirm renal dosing in product SmPC / primary label.
Hepatic

Review hepatic impairment dosing; monitor LFTs if agent is hepatically cleared or hepatotoxic.

03 Clinical use

Use, effects & interactions

Indications

  • INDICATIONS AND USAGE Epilepsy Carbamazepine is indicated for use as an anticonvulsant drug.
  • Evidence supporting efficacy of carbamazepine as an anticonvulsant was derived from active drug-controlled studies that enrolled patients with the following seizure types: 1.
  • Partial seizures with complex symptomatology (psychomotor, temporal lobe).
  • Patients with these seizures appear to show greater improvement than those with other types. 2.
  • Generalized tonic-clonic seizures (grand mal). 3.
  • Mixed seizure patterns which include the above, or other partial or generalized seizures.
  • Absence seizures (petit mal) do not appear to be controlled by carbamazepine (see PRECAUTIONS , General).
  • Trigeminal Neuralgia Carbamazepine is indicated in the treatment of the pain associated with true trigeminal neuralgia.
  • Beneficial results have also been reported in glossopharyngeal neuralgia.
  • This drug is not a simple analgesic and should not be used for the relief of trivial aches or pains.

Adverse effects

  • ADVERSE REACTIONS If adverse reactions are of such severity that the drug must be discontinued, the physician must be aware that abrupt discontinuation of any anticonvulsant drug in a responsive epileptic patient may lead to seizures or even status epilepticus with its life-threatening hazards.
  • The most severe adverse reactions have been observed in the hemopoietic system and skin (see BOXED WARNING), the liver, and the cardiovascular system.
  • The most frequently observed adverse reactions, particularly during the initial phases of therapy, are dizziness, drowsiness, unsteadiness, nausea, and vomiting.
  • To minimize the possibility of such reactions, therapy should be initiated at the lowest dosage recommended.
  • The following additional adverse reactions have been reported: Hemopoietic System : Aplastic anemia, agranulocytosis, pancytopenia, bone marrow depression, thrombocytopenia, leukopenia, leukocytosis, eosinophilia, acute intermittent porphyria, variegate porphyria, porphyria cutanea tarda.
  • Skin : Toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) (see BOXED WARNING), Acute Generalized Exanthematous Pustulosis (AGEP), pruritic and erythematous rashes, urticaria, photosensitivity reactions, alterations in skin pigmentation, exfoliative dermatitis, erythema multiforme and nodosum, purpura, aggravation of disseminated lupus erythematosus, alopecia, diaphoresis, onychomadesis and hirsutism.
  • In certain cases, discontinuation of therapy may be necessary.
  • Cardiovascular System : Congestive heart failure, edema, aggravation of hypertension, hypotension, syncope and collapse, aggravation of coronary artery disease, arrhythmias and AV block, thrombophlebitis, thromboembolism (e.g., pulmonary embolism), and adenopathy or lymphadenopathy.
  • Some of these cardiovascular complications have resulted in fatalities.
  • Myocardial infarction has been associated with other tricyclic compounds.
  • Liver : Abnormalities in liver function tests, cholestatic and hepatocellular jaundice, hepatitis, very rare cases of hepatic failure.
  • Pancreatic : Pancreatitis.
  • Respiratory System : Pulmonary hypersensitivity characterized by fever, dyspnea, pneumonitis, or pneumonia.
  • Genitourinary System : Urinary frequency, acute urinary retention, oliguria with elevated blood pressure, azotemia, renal failure, and impotence.
  • Professional use: confirm indication, dose, duration, monitoring and patient counselling points against current Kenya STG / EML and the product SmPC.
  • Document allergy status and key interactions.
04 Pharmacology

Mechanism & disposition

Mechanism of Action Carbamazepine has demonstrated anticonvulsant properties in rats and mice with electrically and chemically induced seizures.

Mechanism of Action Carbamazepine has demo…It appears to act by reducing polysynaptic…Carbamazepine greatly reduces or abolishes…
Read complete mechanism

Mechanism of Action Carbamazepine has demonstrated anticonvulsant properties in rats and mice with electrically and chemically induced seizures. It appears to act by reducing polysynaptic responses and blocking the post-tetanic potentiation. Carbamazepine greatly reduces or abolishes pain induced by stimulation of the infraorbital nerve in cats and rats. It depresses thalamic potential and bulbar and polysynaptic reflexes, including the linguomandibular reflex in cats. Carbamazepine is chemically unrelated to other anticonvulsants or other drugs used to control the pain of trigeminal neuralgia. The mechanism of action remains unknown. The principal metabolite of carbamazepine, carbamazepine-10, 11-epoxide, has anticonvulsant activity as demonstrated in several in vivo animal models of seizures. Though clinical activity for the epoxide has been postulated, the significance of its activity with respect to the safety and efficacy of carbamazepine has not been established.

Onset

Product-specific

Duration

Product-specific

Route

See product SmPC

Half-life

is also variable. Autoinduction is completed after 3 to 5 weeks of a fixed dosing regimen. Initial half-life values range from 25 to 65 hours, decreasing to 12 to 17 hours on repeated doses. Carbamazepine is metabolized in the liver. Cytochrome P450 3A4 was identified as the majo...

05 Special populations

Pregnancy, lactation & diet

Pregnancy

Use only if potential benefit justifies potential risk; prefer agents with better reproductive data when alternatives exist.

Lactation

Assess infant risk vs benefit of maternal therapy; prefer agents with lactation data.

06 Kenya market

Brands & loaded prices

FromKES 479
MedianKES 865
Listings3
BrandManufacturerPackObserved price
CARBAMAZEPINE Not recorded 200MG 100`S(NEUROTROL) KES 479.45Daima Chemist price-list reference ↗ Source date not recorded · verify current price
TEGRETOL 2% SUSP FL Not recorded 150ML KES 865.34Daima Chemist price-list reference ↗ Source date not recorded · verify current price
TEGRETOL CR Not recorded 400MG 30`S KES 1,070.10Daima Chemist price-list reference ↗ Source date not recorded · verify current price
07 Provenance

Sources & review state

Primary sourceLocal active-ingredient clinical extract; FDA drug label via OpenFDA/DailyMed; Professional class pharmacology (Therapeutic agent (verify pharmacological class))
Last reviewedNot recorded
EvidenceSource-linked
Open source document ↗

Decision support only. Confirm patient-specific decisions against the current product SmPC, Kenya STG/EML, and professional judgement.