Oral diazepam (Valium), given at times of fever, safely reduces the risk of febrile seizure recurrence in infants and children, according to a study published in the July 8 issue of the New England Journal of Medicine * and funded by the National Institute of Neurological Disorders and Stroke (NINDS). Febrile seizures are fever-triggered convulsions that occur in approximately 3-4 percent of all children in the United States.
Diazepam is a benzodiazepine. It works by slowing down the movement of chemicals in the brain. This results in a reduction in nervous tension (anxiety) and muscle spasm, and also causes sedation.
Thursday, February 12, 2009
ANTIEPILEPTIC MEDICATIONS
CARBAMAZEPINE
Mechanism of Action :
Carbamazepine reduces polysynaptic responses and blocks post-tetanic potentiation. It is effective in partial and generalised convulsions as well as in mixed types but not in petit mal seizures. It reduces or abolishes pain in trigeminal and glossopharyngeal neuralgia.
Indication, Dosage and Frequency :
Oral
EPILEPSY
Adult: Initially, 100-200 mg once or bid gradually increased by increments of 100-200 mg every 2 wk. Maintenance: 0.8-1.2 g daily in divided doses. Max dose: 2 g daily.
Child: ≤1 yr: 100-200 mg daily, 1-5 yr: 200-400 mg daily, 5-10 yr: 400-600 mg daily, 10-15 yr: 0.6-1 g daily. Alternatively, 10-20 mg/kg daily in divided doses.
TRIGEMINAL NEURALGIA
Adult: Initially, 100 mg once or bid gradually increased as necessary. Maintenance: 400-800 mg daily in 2-4 divided doses. Max: 1.2 g daily.
PROPHYLAXIS OF BIPOLAR DISORDER
Adult: Initially, 400 mg daily in divided doses gradually increased if necessary. Maintenance: 400-600 mg daily. Max: 1.6 g daily.
Rectal
EPILEPSY
Adult: 250 mg every 6 hr for patients incapable of oral treatment
Interactions :
Reduces tolerance to alcohol; shortens T½ of doxycycline. Decreased efficacy of oral contraceptives when used with carbamazepine. Increased plasma concentrations of carbamazepine by propoxyphene. Serum level decreases with phenytoin, phenobarbital, primidone
Mechanism of Action :
Carbamazepine reduces polysynaptic responses and blocks post-tetanic potentiation. It is effective in partial and generalised convulsions as well as in mixed types but not in petit mal seizures. It reduces or abolishes pain in trigeminal and glossopharyngeal neuralgia.
Indication, Dosage and Frequency :
Oral
EPILEPSY
Adult: Initially, 100-200 mg once or bid gradually increased by increments of 100-200 mg every 2 wk. Maintenance: 0.8-1.2 g daily in divided doses. Max dose: 2 g daily.
Child: ≤1 yr: 100-200 mg daily, 1-5 yr: 200-400 mg daily, 5-10 yr: 400-600 mg daily, 10-15 yr: 0.6-1 g daily. Alternatively, 10-20 mg/kg daily in divided doses.
TRIGEMINAL NEURALGIA
Adult: Initially, 100 mg once or bid gradually increased as necessary. Maintenance: 400-800 mg daily in 2-4 divided doses. Max: 1.2 g daily.
PROPHYLAXIS OF BIPOLAR DISORDER
Adult: Initially, 400 mg daily in divided doses gradually increased if necessary. Maintenance: 400-600 mg daily. Max: 1.6 g daily.
Rectal
EPILEPSY
Adult: 250 mg every 6 hr for patients incapable of oral treatment
Interactions :
Reduces tolerance to alcohol; shortens T½ of doxycycline. Decreased efficacy of oral contraceptives when used with carbamazepine. Increased plasma concentrations of carbamazepine by propoxyphene. Serum level decreases with phenytoin, phenobarbital, primidone
CLONAZEPAM
Mechanism of Action :
Clonazepam is an effective anticonvulsant. It raises the threshold for propagation of seizure activity and prevents generalisation of focal or local activity. Clinically, it improves focal epilepsy and generalised seizures. It is also believed to enhance the activity of GABA, and acts as anxiolytic.
Indication, Dosage and Frequency :
Oral
EPILEPSY
Adult: Initially, 1 mg given at night for 4 nights, gradually increased over 2-4 wk. Maintenance: 4-8 mg daily. Max: 20 mg/day
Child: 1-5 yr: 250 mcg daily; 5-12 yr: 500 mcg daily. Maintenance (given in 2-4 divided doses): Infants: 0.5-1 mg daily; 1-5 yr: 1-3 mg daily; 5-12 yr: 3-6 mg daily. Max: 200 mcg/kg/day
Elderly: Initially, 500 mcg at night for 4 nights, may gradually increase over 2-4 wk.
PANIC DISORDER
Adult: Initially, 250 mcg bid, increased after 3 days up to 1 mg daily. Max: 4 mg daily.
Intravenous
EMERGENCY MANAGEMENT OF STATUS EPILEPTICUS
Adult: 1 mg as inj or infusion given over at least 2 min, repeated if necessary.
Child: and infants: 500 mcg as inj or infusion given over at least 2 min, repeated if necessary
Interactions :
Carbamazepine, phenobarbitone or phenytoin may accelerate clonazepam metabolism.
Clonazepam is an effective anticonvulsant. It raises the threshold for propagation of seizure activity and prevents generalisation of focal or local activity. Clinically, it improves focal epilepsy and generalised seizures. It is also believed to enhance the activity of GABA, and acts as anxiolytic.
Indication, Dosage and Frequency :
Oral
EPILEPSY
Adult: Initially, 1 mg given at night for 4 nights, gradually increased over 2-4 wk. Maintenance: 4-8 mg daily. Max: 20 mg/day
Child: 1-5 yr: 250 mcg daily; 5-12 yr: 500 mcg daily. Maintenance (given in 2-4 divided doses): Infants: 0.5-1 mg daily; 1-5 yr: 1-3 mg daily; 5-12 yr: 3-6 mg daily. Max: 200 mcg/kg/day
Elderly: Initially, 500 mcg at night for 4 nights, may gradually increase over 2-4 wk.
PANIC DISORDER
Adult: Initially, 250 mcg bid, increased after 3 days up to 1 mg daily. Max: 4 mg daily.
Intravenous
EMERGENCY MANAGEMENT OF STATUS EPILEPTICUS
Adult: 1 mg as inj or infusion given over at least 2 min, repeated if necessary.
Child: and infants: 500 mcg as inj or infusion given over at least 2 min, repeated if necessary
Interactions :
Carbamazepine, phenobarbitone or phenytoin may accelerate clonazepam metabolism.
CLORAZEPATE
Mechanism of Action :
Clorazepate binds to stereospecific benzodiazepine receptors on the postsynaptic GABA neuron within the central nervous system, limbic system, reticular formation resulting to an increase in chloride ion permeability which further leads to hyperpolarisation and stabilisation.
Onset: 1-2 hrs.
Duration: 8-24 hrs.
Indication, Dosage and Frequency
Oral
ANXIETY
Adult: 7.5 mg tid.
Elderly: and debilitated patients: Initiate at lower dose and adjust slowly.
ALCOHOL WITHDRAWAL SYNDROME
Adult: 90 mg daily in divided doses.
Child: 9-12 yr old: 60 mg in divided doses.
Elderly: and debilitated patients: Initiate at lower dose and adjust slowly.
EPILEPSY
Adult: 90 mg daily in divided doses.
Child: 9-12 yr old: 60 mg in divided doses.
Elderly: and debilitated patients: Initiate at lower dose and adjust slowly.
Interactions :
Potentiates CNS effects of narcotic analgesics, barbiturates, phenothiazines, ethanol, antihistamines, MAO Inhibitors, sedative-hypnotics, cyclic antidepressants. CYP3A4 inhibitors eg, amprenavir, cimetidine, ciprofloxacin, clarithromycin may increase serum conc and toxicity of clorazepate. Carbamazepine, rifampin and rifabutin may decrease clorazepate therapeutic effects by enhancement of clorazepate metabolism.
Grapefruit juice increases serum conc or toxicity risk of clorazepate. Herbs or nutraceuticals eg, valerian, St. John's wort, kava kava and gotu kola may increase CNS depression upon concomitant admin with clorazepate.
Clorazepate binds to stereospecific benzodiazepine receptors on the postsynaptic GABA neuron within the central nervous system, limbic system, reticular formation resulting to an increase in chloride ion permeability which further leads to hyperpolarisation and stabilisation.
Onset: 1-2 hrs.
Duration: 8-24 hrs.
Indication, Dosage and Frequency
Oral
ANXIETY
Adult: 7.5 mg tid.
Elderly: and debilitated patients: Initiate at lower dose and adjust slowly.
ALCOHOL WITHDRAWAL SYNDROME
Adult: 90 mg daily in divided doses.
Child: 9-12 yr old: 60 mg in divided doses.
Elderly: and debilitated patients: Initiate at lower dose and adjust slowly.
EPILEPSY
Adult: 90 mg daily in divided doses.
Child: 9-12 yr old: 60 mg in divided doses.
Elderly: and debilitated patients: Initiate at lower dose and adjust slowly.
Interactions :
Potentiates CNS effects of narcotic analgesics, barbiturates, phenothiazines, ethanol, antihistamines, MAO Inhibitors, sedative-hypnotics, cyclic antidepressants. CYP3A4 inhibitors eg, amprenavir, cimetidine, ciprofloxacin, clarithromycin may increase serum conc and toxicity of clorazepate. Carbamazepine, rifampin and rifabutin may decrease clorazepate therapeutic effects by enhancement of clorazepate metabolism.
Grapefruit juice increases serum conc or toxicity risk of clorazepate. Herbs or nutraceuticals eg, valerian, St. John's wort, kava kava and gotu kola may increase CNS depression upon concomitant admin with clorazepate.
DIAZEPAM
Mechanism of Action :
Diazepam is a long-acting benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant and amnestic properties. It increases neuronal membrane permeability to chloride ions by binding to stereospecific benzodiazepine receptors on the postsynaptic GABA neuron within the CNS and enhancing the GABA inhibitory effects resulting in hyperpolarisation and stabilisation.
Indication, Dosage and Frequency :
Oral
SHORT-TERM MANAGEMENT OF ANXIETY
Adult: 2 mg tid. Max: 30 mg daily.
Elderly: Dose reduction may be required.
INSOMNIA ASSOCIATED WITH ANXIETY
Adult: 5-15 mg at bedtime.
Elderly: Dose reduction may be required.
SLEEPWALKING
Child: and adolescents (up to 18 yr): 1-5 mg at bedtime.
Elderly: Dose reduction may be required.
NIGHT TERRORS
Child: and adolescents (up to 18 yr): 1-5 mg at bedtime.
Elderly: Dose reduction may be required.
ANAESTHETIC PREMEDICATION
Adult: 5-15 mg given before general anaesthesia.
Child: 1-12 mth: 250 mcg/kg; 1-5 yr: 2.5 mg; 5-12 yr: 5 mg.
Elderly: Dose reduction may be required.
ADJUNCT IN THE MANAGEMENT OF SEIZURES
Adult: 2-60 mg daily in divided doses.
Elderly: Dose reduction may be required.
MUSCLE SPASMS
Adult: 2-15 mg daily in divided doses, increased up to 60 mg daily in severe spastic disorders e.g. cerebral palsy. Max: 60 mg/day.
Child: 1-12 mth: 250 mcg/kg; 1-5 yr: 2.5 mg; 5-12 year: 5 mg; 12-18 yr: 10 mg. Max: 40 mg/day.
Elderly: Dose reduction may be required.
ACUTE SYMPTOMS OF ALCOHOL WITHDRAWAL
Adult: 5-20 mg repeated after 2-4 hr if necessary. Alternatively, 10 mg 3-4 times daily on the 1st day reduced to 5 mg 3-4 times daily as required.
Elderly: Dose reduction may be required.
Intravenous
ANAESTHETIC PREMEDICATION
Adult: 100-200 mcg/kg.
Child: >1 mth: 100-200 mcg/kg. Max: 1 mth-12 yr: 5 mg/day; 12-18 yr: 20 mg/day.
Elderly: Dose reduction may be required.
MUSCLE SPASM ASSOCIATED WITH TETANUS
Adult: 100-300 mcg/kg given every 1-4 hr by IV inj. Alternatively, 3-10 mg/kg is given over 24 hr by continuous IV infusion or by nasoduodenal tube using a suitable liquid oral dose preparation.
Child: >1 mth: 100-300 mcg/kg given every 1-4 hr by IV inj. Alternatively, 3-10 mg/kg is given over 24 hr by continuous IV infusion or by nasoduodenal tube using a suitable liquid oral dose preparation.
Elderly: Dose reduction may be required.
Interactions :
Increased clearance of diazepam when used with phenytoin, carbamazepine and phenobarbital. Reversible deterioration of parkinsonism may occur when given together with levodopa. Combination with lithium may produce hypothermia.
Grape juice may increase serum levels and toxicity.
Diazepam is a long-acting benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant and amnestic properties. It increases neuronal membrane permeability to chloride ions by binding to stereospecific benzodiazepine receptors on the postsynaptic GABA neuron within the CNS and enhancing the GABA inhibitory effects resulting in hyperpolarisation and stabilisation.
Indication, Dosage and Frequency :
Oral
SHORT-TERM MANAGEMENT OF ANXIETY
Adult: 2 mg tid. Max: 30 mg daily.
Elderly: Dose reduction may be required.
INSOMNIA ASSOCIATED WITH ANXIETY
Adult: 5-15 mg at bedtime.
Elderly: Dose reduction may be required.
SLEEPWALKING
Child: and adolescents (up to 18 yr): 1-5 mg at bedtime.
Elderly: Dose reduction may be required.
NIGHT TERRORS
Child: and adolescents (up to 18 yr): 1-5 mg at bedtime.
Elderly: Dose reduction may be required.
ANAESTHETIC PREMEDICATION
Adult: 5-15 mg given before general anaesthesia.
Child: 1-12 mth: 250 mcg/kg; 1-5 yr: 2.5 mg; 5-12 yr: 5 mg.
Elderly: Dose reduction may be required.
ADJUNCT IN THE MANAGEMENT OF SEIZURES
Adult: 2-60 mg daily in divided doses.
Elderly: Dose reduction may be required.
MUSCLE SPASMS
Adult: 2-15 mg daily in divided doses, increased up to 60 mg daily in severe spastic disorders e.g. cerebral palsy. Max: 60 mg/day.
Child: 1-12 mth: 250 mcg/kg; 1-5 yr: 2.5 mg; 5-12 year: 5 mg; 12-18 yr: 10 mg. Max: 40 mg/day.
Elderly: Dose reduction may be required.
ACUTE SYMPTOMS OF ALCOHOL WITHDRAWAL
Adult: 5-20 mg repeated after 2-4 hr if necessary. Alternatively, 10 mg 3-4 times daily on the 1st day reduced to 5 mg 3-4 times daily as required.
Elderly: Dose reduction may be required.
Intravenous
ANAESTHETIC PREMEDICATION
Adult: 100-200 mcg/kg.
Child: >1 mth: 100-200 mcg/kg. Max: 1 mth-12 yr: 5 mg/day; 12-18 yr: 20 mg/day.
Elderly: Dose reduction may be required.
MUSCLE SPASM ASSOCIATED WITH TETANUS
Adult: 100-300 mcg/kg given every 1-4 hr by IV inj. Alternatively, 3-10 mg/kg is given over 24 hr by continuous IV infusion or by nasoduodenal tube using a suitable liquid oral dose preparation.
Child: >1 mth: 100-300 mcg/kg given every 1-4 hr by IV inj. Alternatively, 3-10 mg/kg is given over 24 hr by continuous IV infusion or by nasoduodenal tube using a suitable liquid oral dose preparation.
Elderly: Dose reduction may be required.
Interactions :
Increased clearance of diazepam when used with phenytoin, carbamazepine and phenobarbital. Reversible deterioration of parkinsonism may occur when given together with levodopa. Combination with lithium may produce hypothermia.
Grape juice may increase serum levels and toxicity.
ETHOSUXIMIDE
Mechanism of Action :
Ethosuximide is used mainly in the management of absence (petite mal) seizures. It is usually ineffective in the management of partial seizures with complex symptomatology or tonic-clonic seizures.
Indication, Dosage and Frequency :
Oral
ABSENCE SEIZURES
Adult: Initially, 500 mg daily, may increase in steps of 250 mg at intervals of 4-7 days. Usual dose: 1-1.5 g daily. Optimum plasma concentration: 40-100 mg/L (300-700 micromol/L). Max: Up to 2 g in some patients. Strict supervision is recommended if dose >1.5 g daily.
Child: <6 yr: Initially, 250 mg daily, may increase gradually to usual dose of 20 mg/kg daily. ≥6 yr: Initially, 500 mg daily, may increase in steps of 250 mg at intervals of 4-7 days. Usual dose: 1-1.5 g daily. Max: <6 yr: Up to 1 g/day and ≥6 yr: 2 g/day .
Interactions :
Isoniazid may increase the serum concentration of ethosuximide, leading to toxicity. Antipsychotics, antidepressants, MAOIs, and mefloquine may antagonise anticonvulsant effects of ethosuximide. Plasma conc of ethosuximide may be reduced by carbamazepine, phenobarbital, phenytoin, and primidone; and affected by valproate. Chloroquine or hydroxychloroquine may increase risk of convulsions.
Ethosuximide is used mainly in the management of absence (petite mal) seizures. It is usually ineffective in the management of partial seizures with complex symptomatology or tonic-clonic seizures.
Indication, Dosage and Frequency :
Oral
ABSENCE SEIZURES
Adult: Initially, 500 mg daily, may increase in steps of 250 mg at intervals of 4-7 days. Usual dose: 1-1.5 g daily. Optimum plasma concentration: 40-100 mg/L (300-700 micromol/L). Max: Up to 2 g in some patients. Strict supervision is recommended if dose >1.5 g daily.
Child: <6 yr: Initially, 250 mg daily, may increase gradually to usual dose of 20 mg/kg daily. ≥6 yr: Initially, 500 mg daily, may increase in steps of 250 mg at intervals of 4-7 days. Usual dose: 1-1.5 g daily. Max: <6 yr: Up to 1 g/day and ≥6 yr: 2 g/day .
Interactions :
Isoniazid may increase the serum concentration of ethosuximide, leading to toxicity. Antipsychotics, antidepressants, MAOIs, and mefloquine may antagonise anticonvulsant effects of ethosuximide. Plasma conc of ethosuximide may be reduced by carbamazepine, phenobarbital, phenytoin, and primidone; and affected by valproate. Chloroquine or hydroxychloroquine may increase risk of convulsions.
GABAPENTIN
Mechanism of Action :
Gabapentin is structurally related to the neurotransmitter GABA but is neither a GABA agonist nor antagonist. Gabapentin-binding sites have been identified throughout the brain tissues e.g. neocortex and hippocampus. However, the exact mechanism of action is still unknown.
Oral
EPILEPSY (PARTIAL SEIZURES WITH OR WITHOUT SECONDARY GENERALISATION)
Adult: Initially, 300 mg on the 1st day, 300 mg bid on the 2nd day and 300 mg tid on the 3rd day. Thereafter, may increase dose until effective antiepileptic control is achieved. Usual maintenance range: 0.9-3.6 g daily; daily dose to be taken in 3 equally divided doses and max dosing interval: 12 hr. Max: 4.8 g daily.
Child: 6-12 yr: Initially, 10 mg/kg on the 1st day, 20 mg/kg on the 2nd day and 25-35 mg/kg on the 3rd day. Maintenance: 1200 mg daily (37-50 kg); 900 mg daily (26-36 kg). Total daily dose to be taken in 3 equally divided doses.
NEUROPATHIC PAIN
Adult: Titrate to a max of 1.8 g daily in 3 divided doses.
Interactions :
Cimetidine may reduce gabapentin clearance. Absorption reduced with antacids.
Gabapentin is structurally related to the neurotransmitter GABA but is neither a GABA agonist nor antagonist. Gabapentin-binding sites have been identified throughout the brain tissues e.g. neocortex and hippocampus. However, the exact mechanism of action is still unknown.
Oral
EPILEPSY (PARTIAL SEIZURES WITH OR WITHOUT SECONDARY GENERALISATION)
Adult: Initially, 300 mg on the 1st day, 300 mg bid on the 2nd day and 300 mg tid on the 3rd day. Thereafter, may increase dose until effective antiepileptic control is achieved. Usual maintenance range: 0.9-3.6 g daily; daily dose to be taken in 3 equally divided doses and max dosing interval: 12 hr. Max: 4.8 g daily.
Child: 6-12 yr: Initially, 10 mg/kg on the 1st day, 20 mg/kg on the 2nd day and 25-35 mg/kg on the 3rd day. Maintenance: 1200 mg daily (37-50 kg); 900 mg daily (26-36 kg). Total daily dose to be taken in 3 equally divided doses.
NEUROPATHIC PAIN
Adult: Titrate to a max of 1.8 g daily in 3 divided doses.
Interactions :
Cimetidine may reduce gabapentin clearance. Absorption reduced with antacids.
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