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EPANUTIN is a brand name for Phenytoin. The medicine, its uses, side effects and dosage are the same regardless of brand.
Used for: Control of tonic-clonic seizures (grand mal epilepsy), partial seizures (focal including temporal lobe) or a combination of these, and for the prevention and treatment of seizures occurring during or following neurosurgery and/or severe head injury. Epanutin has also been employed in the treatment of trigeminal…
Verbatim from this product's MHRA label. Tap a section to expand.
For oral administration only.
Dosage:
Dosage should be individualised as there may be wide interpatient variability in phenytoin serum levels with equivalent dosage. Epanutin should be introduced in small dosages with gradual increments until control is achieved or until toxic effects appear.
In some cases, serum level determinations may be necessary for optimal dosage adjustments - the clinically effective level is usually 10 mcg/mL - 20 mcg/mL (40-80 micromoles/l) although some cases of tonic-clonic seizures may be controlled with lower serum levels of phenytoin.
With recommended dosage a period of 7 to 10 days may be required to achieve steady state serum levels with Epanutin and changes in dosage should not be carried out at intervals shorter than 7 to 10 days. Maintenance of treatment should be the lowest dose of anticonvulsant consistent with control of seizures.
Epanutin Capsules, Oral Suspension and Infatabs:
Epanutin Capsules contain phenytoin sodium whereas Epanutin Oral Suspension and Epanutin Infatabs contain phenytoin. Although 100 mg of phenytoin sodium is equivalent to 92 mg of phenytoin on a molecular weight basis, these molecular equivalents are not necessarily biologically equivalent.
Physicians should therefore exercise care in those situations where it is necessary to change the dosage form and serum level monitoring is advised.
Posology Adult Dosage for Seizures:
Initially 3 to 4 mg/kg/day with subsequent dosage adjustment if necessary. For most adults a satisfactory maintenance dose will be 200 mg to 500 mg daily in single or divided doses. Exceptionally, a daily dose outside this range may be indicated.
Dosage should normally be adjusted according to serum levels where assay facilities exist.
Dosing in Special Populations Patients with Renal or Hepatic Disease:
See section
8 Skin and subcutaneous tissue disorders). 4 Hypersensitivity Syndrome/Drug Reaction with Eosinophilia and Systemic Symptoms (HSS/DRESS)), occurrence of rash and should be monitored closely for skin reactions. Patients should seek medical advice from their physician immediately when observing any indicative signs or symptoms.
The highest risk for occurrence of SJS or TEN is within the first weeks of treatment. g. progressive skin rash often with blisters or mucosal lesions) are present, Epanutin treatment should be discontinued. The best results in managing SJS and TEN come from early diagnosis and immediate discontinuation of any suspect drug.
Early withdrawal is associated with a better prognosis. If the patient has developed SJS or TEN with the use of Epanutin, Epanutin must not be re-started in this patient at any time. If the rash is of a milder type (measles-like or scarlatiniform), therapy may be resumed after the rash has completely disappeared.
If the rash recurs upon reinstitution of therapy, further phenytoin medication is contraindicated. The risk of serious skin reactions and other hypersensitivity reactions to phenytoin may be higher in black patients. Studies in patients of Chinese ancestry have found a strong association between the risk of developing SJS/TEN and the presence of human leukocyte antigen HLA- B*1502, an inherited allelic variant of the HLA B gene, in patients using carbamazepine.
Limited evidence suggests that HLA-B*1502 may be a risk factor for the development of SJS/TEN in patients of Asian ancestry taking drugs associated with SJS/TEN, including phenytoin. Consideration should be given to avoiding use of drugs associated with SJS/TEN, including phenytoin, in HLA-B*1502 positive patients when alternative therapies are otherwise equally available.
HLA-B* 1502 may be associated with an increased risk of developing SJS in individuals of Thai and Han Chinese Origin when treated with phenytoin. If these patients are known to be positive for HLA-B*1502, the use of phenytoin should only be considered if the benefits are thought to exceed risks.
4.
Adult Dosage for Trigeminal Neuralgia:
The clinically effective dose has not been established in clinical trials. In adults, 300- 500 mg daily given in divided doses has been reported in the literature. Dosing should be adjusted based on clinical response. Determination of serum phenytoin levels is advised.
2 Special Populations – Age). As with adults the dosage of Epanutin should be titrated to the patient’s individual requirements using the same guidelines. As older people tend to receive multiple drug therapies, the possibility of drug interactions should be borne in mind.
Paediatric population Dosage for Seizures:
Initially, 5 mg/kg/day in two divided doses, with subsequent dosage individualised to a maximum of 300 mg daily. A recommended daily maintenance dosage is usually 4 mg/kg - 8 mg/kg.
Neonates:
The absorption of phenytoin following oral administration in neonates is unpredictable. Furthermore, the metabolism of phenytoin may be depressed. It is therefore especially important to monitor serum levels in the neonate. 1, or other hydantoins.
Co-administration of phenytoin is contraindicated with delavirdine due to the potential for loss of virologic response and possible resistance to delavirdine or to the class of non-nucleoside reverse transcriptase inhibitors. 4 Special warnings and precautions for use General Phenytoin is not effective for absence (petit mal) seizures.
If tonic-clonic (grand mal) and absence seizures are present together, combined drug therapy is needed. Phenytoin is not indicated for seizures due to hypoglycaemia or other metabolic causes. Abrupt withdrawal of phenytoin in epileptic patients may precipitate status epilepticus.
1, or other hydantoins. Co-administration of phenytoin is contraindicated with delavirdine due to the potential for loss of virologic response and possible resistance to delavirdine or to the class of non-nucleoside reverse transcriptase inhibitors.
Not medical advice. Always read the patient information leaflet and follow your prescriber or pharmacist.
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In the Caucasian and Japanese population, the frequency of HLA-B*1502 allele is extremely low, and thus it is not possible at present to conclude on risk association. Adequate information about risk association in other ethnicities is currently not available.
Case-control, genome-wide association studies in Taiwanese, Japanese, Malaysian and Thai patients have identified an increased risk of SCARs in carriers of the decreased function CYP2C9*3 variant. CYP2C9 metabolism Phenytoin is metabolised by the CYP450 CYP2C9 enzyme.
Patients who are carriers of the decreased function CYP2C9*2 or CYP2C9*3 variants (intermediate or poor metabolisers of CYP2C9 substrates) may be at risk of increased phenytoin plasma concentrations and subsequent toxicity. In patients who are known to be carriers of the decreased function CYP2C9*2 or *3 alleles, close monitoring of clinical response is advised and monitoring of plasma phenytoin concentrations may be required.
Angioedema Angioedema has been reported in patients treated with phenytoin and fosphenytoin. 8 Immune system disorders). Hepatic Injury Phenytoin is highly protein bound and extensively metabolised by the liver. Reduced dosage to prevent accumulation and toxicity may therefore be required in patients with impaired liver function.
Where protein binding is reduced, as in uraemia, total serum phenytoin levels will be reduced accordingly. However, the pharmacologically active free drug concentration is unlikely to be altered. Therefore, under these circumstances therapeutic control may be achieved with total phenytoin levels below the normal range of 10 mcg/ml - 20 mcg/ml (40-80 micromoles/l).
Cases of acute hepatotoxicity, including infrequent cases of acute hepatic failure, have been reported with phenytoin. 4 Hypersensitivity Syndrome/Drug Reaction with Eosinophilia and Systemic Symptoms (HSS/DRESS)). Patients with impaired liver function, older patients or those who are gravely ill may show early signs of toxicity.
The risk of hepatotoxicity and other hypersensitivity reactions to phenytoin may be higher in black patients. Haematopoietic System Haematopoietic complications, some fatal, have occasionally been reported in association with administration of phenytoin.
These have included thrombocytopenia, leucopenia, granulocytopenia, agranulocytosis, and pancytopenia with or without bone marrow suppression. There have been a number of reports suggesting a relationship between phenytoin and the development of lymphadenopathy (local and generalised) including benign lymph node hyperplasia, pseudolymphoma, lymphoma, and Hodgkin’s Disease.
Although a cause and effect relationship has not been established, the occurrence of lymphadenopathy indicates the need to differentiate such a condition from other types of lymph node pathology. 4). In all cases of lymphadenopathy, follow-up observation for an extended period is indicated and every effort should be made to achieve seizure control using alternative antiepileptic drugs.
Central Nervous System Effect Serum levels of phenytoin sustained above the optimal range may produce confusional states referred to as “delirium”, “psychosis”, or “encephalopathy”, or rarely irreversible cerebellar dysfunction and/or cerebellar atrophy.
Accordingly, at the first sign of acute toxicity, serum drug level […]
When, in the judgement of the clinician, the need for dosage reduction, discontinuation, or substitution of alternative anti-epileptic medication arises, this should be done gradually. However, in the event of an allergic or hypersensitivity reaction, rapid substitution of alternative therapy may be necessary.
In this case, alternative therapy should be an anti-epileptic drug not belonging to the hydantoin chemical class. Phenytoin may precipitate or aggravate absence seizures and myoclonic seizures. Acute alcohol intake may increase phenytoin serum levels while chronic alcoholism may decrease serum levels.
Due to an increased fraction of unbound phenytoin in patients with renal or hepatic disease, or in those with hypoalbuminemia, the interpretation of total plasma phenytoin concentrations should be made with caution. Unbound concentration of phenytoin may be elevated in patients with hyperbilirubinemia.
Herbal preparations containing St. 5). Suicide Suicidal ideation and behaviour have been reported in patients treated with anti- epileptic agents in several indications. A meta-analysis of randomised placebo controlled trials of anti-epileptic drugs has also shown a small increased risk of suicidal ideation and behaviour.
The mechanism of this risk is not known and the available data do not exclude the possibility of an increased risk for phenytoin. Therefore, patients should be monitored for signs of suicidal ideation and behaviours and appropriate treatment should be considered.
Patients (and caregivers of patients) should be advised to seek medical advice should signs of suicidal ideation or behaviour emerge. 9), but also at recommended phenytoin doses and levels. Hypersensitivity Syndrome/Drug Reaction with Eosinophilia and Systemic Symptoms (HSS/DRESS) Hypersensitivity Syndrome (HSS) or Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) has been reported in patients taking anticonvulsant drugs, including phenytoin.
Some of these events have been fatal or life threatening. HSS/DRESS typically, although not exclusively, presents with fever, rash, and/or lymphadenopathy, in association with other organ system involvement, such as hepatitis, nephritis, haematological abnormalities, myocarditis, myositis or pneumonitis.
Initial symptoms may resemble an acute viral infection. Other common manifestations include arthralgias, jaundice, hepatomegaly, leucocytosis, and eosinophilia. The interval between the first drug exposure and symptoms is usually 2 to 4 weeks but has been reported in individuals receiving anticonvulsants for 3 or more months.
If such signs and symptoms occur, the patient should be evaluated immediately. Phenytoin should be discontinued if an alternative aetiology for the signs and symptoms cannot be established. Patients at higher risk for developing HSS/DRESS include black patients, patients who have experienced this syndrome in the past (with phenytoin or other anticonvulsant drugs), patients who have a family history of this syndrome and immuno-suppressed patients.
The syndrome is more severe in previously sensitized individuals. 8 Skin and subcutaneous tissue disorders). Although serious skin reactions may occur without warning, patients should be advised of the signs and […]