Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2019 Publisher: Sun Pharmaceutical Industries Europe B.V., Polarisavenue 87, 2132 JH Hoofddorp, The Netherlands
Carbamazepine is indicated for:
Since a given dose of carbamazepine oral suspension will produce higher peak levels than the same dose in tablet form, it is advisable to start with low doses of the liquid and to increase them slowly so as to avoid adverse effects on the central nervous system such as dizziness and lethargy.
When switching a patient from tablets to liquid the same overall dose may be used but in smaller, more frequent, doses.
Before deciding to initiate treatment, patients of Han Chinese and Thai origin should whenever possible be screened for HLA-B*1502 as this allele strongly predicts the risk of severe carbamazepine-associated Stevens-Johnson syndrome (see information on genetic testings and cutaneous reactions in section 4.4).
The dose of carbamazepine should be adjusted to the needs of the individual patient to achieve adequate control of seizures. Determination of plasma levels may help in establishing the optimum dosage. In the treatment of epilepsy, the dose of carbamazepine usually requires total plasma-carbamazepine concentrations of about 4 to 12 micrograms/ml (17 to 50 micromoles/litre) (see warnings and precautions).
It is advised that with all formulations of carbamazepine, a gradually increasing dosage scheme is used and this should be adjusted to suit the needs of the individual patient.
Carbamazepine should be taken in a number of divided doses although initially 100-200 mg once to twice daily is recommended. This may be followed by a slow increase until the best response is obtained, often 800-1200 mg daily. In some instances, 1600 mg or even 2000 mg daily may be necessary.
Due to the potential for drug interactions, the dosage of carbamazepine should be selected with caution in elderly patients.
It is advised that with all formulations of carbamazepine, a gradually increasing dosage scheme is used and this should be adjusted to suit the needs of the individual patient.
Usual dosage 10-20 mg/kg bodyweight daily in several divided doses.
Wherever possible anti-epileptic agents should be prescribed as the sole drug anti-epileptic agent but if used in polytherapy, the same incremental dosage pattern is advised.
When carbamazepine is added to existing antiepileptic therapy, this should be done gradually while maintaining or, if necessary, adapting the dosage of the other antiepileptic(s) (see 4.5 Interaction with other Medicaments and other forms of Interaction).
Slowly raise the initial dosage of 200-400 mg daily until freedom from pain is achieved (normally at 200 mg 3-4 times daily). In the majority of patients a dosage of 200 mg 3 or 4 times a day is sufficient to maintain a pain free state. In some instances, doses of 1600 mg carbamazepine daily may be needed. However, once the pain is in remission, the dosage should be gradually reduced to the lowest possible maintenance level. Maximum recommended dose is 1200 mg/day. When pain relief has been obtained, attempts should be made to gradually discontinue therapy, until another attack occurs.
Dosage in Trigeminal neuralgia:
Due to drug interactions and different antiepileptic drug pharmacokinetics, the dosage of carbamazepine should be selected with caution in elderly patients.
In elderly patients, an initial dose of 100 mg twice daily is recommended. The initial dosage of 100 mg twice daily should be slowly raised daily until freedom from pain is achieved (normally at 200 mg 3 to 4 times daily). The dosage should then be gradually reduced to the lowest possible maintenance level. Maximum recommended dose is 1200 mg/day. When pain relief has been obtained, attempts should be made to gradually discontinue therapy, until another attack occurs.
Initial starting dose of 400 mg daily, in divided doses, increasing gradually until symptoms are controlled or a total of 1600 mg given in divided doses is reached. The usual dosage range is 400-600 mg daily, given in divided doses.
No data are available on the pharmacokinetics of carbamazepine in patients with impaired hepatic or renal function.
Carbamazepine oral suspension is given orally, usually in two or three divided doses. Carbamazepine oral suspension (oral suspension should be shaken before use) may be taken during, after or between meals.
The presenting signs and symptoms of overdosage involve the central nervous, cardiovascular, respiratory systems and the adverse drug reactions mentioned under section 4.8.
Central nervous system: CNS depression; disorientation, depressed level of consciousness, somnolence, agitation, hallucination, coma; blurred vision, slurred speech, dysarthria, nystagmus, ataxia, dyskinesia, initially hyperreflexia, later hyporeflexia; convulsions, psychomotor disturbances, myoclonus, hypothermia, mydriasis.
Respiratory system: Respiratory depression, pulmonary oedema.
Cardiovascular system: Tachycardia, hypotension and at times hypertension, conduction disturbance with widening of QRS complex; syncope in association with cardiac arrest.
Gastro-intestinal system: Vomiting, delayed gastric emptying, reduced bowel motility.
Musculoskeletal system: There have been some cases which reported rhabdomyolysis in association with carbamazepine toxicity.
Renal function: Retention of urine, oliguria or anuria; fluid retention, water intoxication due to ADH-like effect of carbamazepine.
Laboratory findings: Hyponatraemia, possibly metabolic acidosis, possibly hyperglycaemia, increased muscle creatine phosphokinase.
There is no specific antidote.
Management should initially be guided by the patient’s clinical condition; admission to hospital. Measurement of the plasma level to confirm carbamazepine poisoning and to ascertain the size of the overdose.
Evacuation of the stomach, gastric lavage, and administration of activated charcoal. Delay in evacuating the stomach may result in delayed absorption, leading to relapse during recovery from intoxication. Supportive medical care in an intensive care unit with cardiac monitoring and careful correction of electrolyte imbalance.
Charcoal haemoperfusion has been recommended. Hemodialysis is the effective treatment modality in the management of the carbamazepine overdose.
Relapse and aggravation of symptomatology on the 2nd and 3rd day after overdose, due to delayed absorption, should be anticipated.
Shelf life: 2 years.
Do not store above 25°C.
Keep the bottle tightly closed between doses.
PET/Glass bottles using a polypropylene child resistant plastic cap.
Pack sizes: 300 ml & 500 ml.
Not all pack sizes may be marketed.
No special requirements.
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