Duration of Time Between Intramuscular Injection of Clonazepam and Onset of Cerebral Electrical Charges in the Monkey.

Clonazepam was administered to monkeys by intramuscular injection at doses of 0.5 and 1.0 mgKg. Changes in EEG pattern, heart rate and behavior were noted following the injection in order to determine the duration of time between injection of the drug and changes in cerebral electrical activity. The first changes occurred about four minutes after administration and consisted of an increase in EEG frequency, appearance of paroxysms of high voltage, multiple sharp waves and a slight decrease in heart rate. Most monkeys appeared slightly sedated at this time. Within eight minutes of receiving the drug, the EEG record was dominated with high voltage, sharp waves and the heart rate decreased 10 of control value. The degree of sedation was the main difference noted between the two doses, as the time between administration and onset of activity and EEG change was similar for both doses.