PHENOBARBITAL BRISTOL LABS

Posology Adults:

The usual dose is 60 – 180mg daily taken at night. Children: 5- 8mg/kg body weight daily.

Elderly:

Phenobarbital clearance diminishes in the elderly. Therefore, the dose of phenobarbital is usually lower in elderly patients. The dose of phenobarbital should be adjusted to meet the needs to individual patients. This usually requires plasma concentration of 15 to 40 micrograms/ml (65 to 170 micromoles/litre).

Method of Administration For oral administration.

• Blood and the lymphatic system disorders: megaloblastic anaemia (due to folate deficiency), agranulocytosis, thrombocytopenia. • Musculoskeletal and connective tissue disorders: Dupuytren's contracture, frozen shoulder, arthralgia, osteomalacia, rickets.

There have been reports of decreased bone mineral density, osteopenia, osteoporosis and fractures in patients on long-term therapy with phenobarbital. The mechanism by which phenobarbital affects bone metabolism has not been identified.

• Reproductive and breast disorders: Peyronie’s disease • Psychiatric disorders: paradoxical reaction (unusual excitement), hallucinations, restlessness and confusion in the elderly, mental depression, memory and cognitive impairment, drowsiness, lethargy.

• Nervous system disorders: hyperactivity, behavioral disturbances in children, ataxia, nystagmus. • Cardiac disorders: hypotension. • Respiratory disorders: respiratory depression. • Hepato-bilary: hepatitis, cholestasis. • Skin and subcutaneous tissue disorders: allergic skin reactions (maculopapular morbilliform or scarlatiniform rashes), other skin reactions such as exfoliative dermatitis, erythema multiforme are rare.

4). • General disorders and administration site conditions: antiepileptic hypersensitivity syndrome (features include fever, rash, lymphadenopathy, lymphocytosis, eosinophilia, haematological abnormalities, hepatic and other organ involvement including renal and pulmonary systems which may become life threatening).

Reporting of Suspected Adverse Reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

Life-threatening cutaneous reactions Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported with the use of Phenobarbital. Patients should be advised of the signs and symptoms and monitored closely for skin reactions.

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, Phenobarbital 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 Phenobarbital, Phenobarbital must not be re-started in this patient at any time. 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 Phenobarbital.

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.

Women of childbearing potential Phenobarbital may cause foetal harm when administered to a pregnant woman. 6). Phenobarbital should not be used in women of childbearing potential unless the potential benefit is judged to outweigh the risks following consideration of other suitable treatment options.

Women of childbearing potential should be fully informed of the potential risk to the foetus if they take phenobarbital during pregnancy. A pregnancy test to rule out pregnancy should be considered prior to commencing treatment with phenobarbital in women of childbearing potential.

Women of childbearing potential should use highly effective contraception during treatment and for 2 months after the last dose. Due to enzyme induction, phenobarbital may result in a failure of the therapeutic effect of oral contraceptive drugs containing oestrogen and/or progesterone.

6). Women planning a pregnancy should be advised to consult in advance with her physician so that adequate counselling can be provided and appropriate other treatment options can be discussed prior to conception and before contraception is discontinued.

Women of childbearing potential should be counselled to contact her doctor immediately if she becomes pregnant or thinks she may be pregnant while on treatment with phenobarbital. Care should be used in the following situations: • Respiratory depression (avoid if severe) • Young, debilitated or senile patients • Renal impairment • Existing liver disease • Sudden withdrawal should be avoided as severe withdrawal syndrome (rebound insomnia, anxiety, tremor, dizziness, nausea, fits and delirium) may be precipitated • Acute chronic pain –paradoxical excitement may be induced or important symptoms masked.

• Prolonged use may result in dependence of the alcohol-barbiturate type. Care should be taken in treating patients with a history of drug abuse or alcoholism. Important information regarding the ingredients in this medicine Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.

1 • Acute intermittent porphyia • Severe respiratory depression • Severe renal or hepatic impairment