Clonazepam reduces the nerve transmission in the motor cortex which suppresses the spike and wave discharge in absence seizures. Its mechanism is believed to be related to its ability to enhance the activity of GABA. Clinically, it improves focal epilepsy and generalised seizures.
Dosage must be determined in each patient according to clinical response and tolerance.
Children: The initial dose for infants and children (up to 10 years of age or 30 kg of body weight) should be between 0.01 and 0.03 mg/kg/day and should not exceed 0.05 mg/kg/day given in two or three divided doses. Dosage should be increased by not more than 0.25 to 0.50 mg every third day until a maintenance dose of 0.1 to 0.2 mg/kg of body weight has been reached, unless seizures are controlled or side effects preclude further increase. Whenever possible, the daily dose should be divided into three equal doses. If doses are not equally divided, the larger dose should be given before retiring.
Adults: 1 mg (elderly 500 micrograms) initially at night for 4 nights, increased according to response over 2-4 weeks to usual maintenance dose of 4-8 mg usually at night (may be given in 3-4 divided doses if necessary). Dosage may be increased in increments of 0.5 to 1 mg every three days until seizures are adequately controlled. A recommended maintenance dose for adults is 8 to 10 mg/day in three divided doses. Dosages in excess of 20 mg/day should be administered with caution.The use of multiple anticonvulsants may result in an increase of depressant adverse effects.This should be borne in mind whenever Clonazepam is added to an already existing anticonvulsant regimen.
Infants and children: half of a vial (0.5 mg) by slow IV injection or by IV infusion.
Adults: 1 vial (1 mg) by slow IV injection or by IV infusion. This dose can be repeated as required (1 – 4 mg are usually sufficient to reverse the status). In adults, the rate of injection must not exceed 0.25 – 0.5 mg per minute (0.5 – 1.0 ml of the prepared solution) and a total dose of 10 mg should not be exceeded.
Slow intravenous injection: The contents of the vial must be diluted with 1 ml of water for injection prior to administration so as to avoid local irritation of the veins. The injection solution should be prepared immediately before use. IV injection should be administered slowly with continuous monitoring of EEG, respiration and blood pressure.
Intravenous infusion: Clonazepam (the vial) can be diluted for infusion in a ratio of 1 vial (1 mg) to at least 85 ml diluting media. The diluting media can be any of the following: sodium chloride 0.9%; sodium chloride 0.45% + glucose 2.5%; glucose 5% or glucose 10%. These mixtures are stable for 24 hours at room temperature. Infusion bags other than PVC should be used for infusing Clonazepam. If PVC infusion bags are used then the mixture should be infused immediately or within 4 hours. The infusion time should not exceed 8 hours. Do not prepare Clonazepam infusions using sodium bicarbonate solution, as precipitation of the solution may occur.
Intramuscular injection: The IM route should be used only in exceptional cases or if IV administration is not feasible.