Clonazepam
Mechanism :
Clonazepam is a benzodiazepine. The precise mechanism by which clonazepam exerts its antiseizure effects is unknown, although it is believed to be related to its ability to enhance the activity of gamma aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system.
Indication :
- Myoclonic seizures
- Status epilepticus
- Absence seizures
- Infantile spasm
- Refractory seizure
Contraindications :
Clonazepam should not be used in patients with a history of sensitivity to benzodiazepines or clinical or biochemical evidence of significant liver disease. It is contraindicated in acute narrow angle glaucoma.
Dosing :
<10 years or <30 kg:
0.01-0.03 mg/kg/day PO in 8 hourly divided doses; increase by 0.25-0.5 mg/day every 3 days to a maximum of 0.1-0.2 mg/kg/day PO in 8 hourly divided doses.
Maximum dose: 20 mg/day.
Adverse Effect :
Somnolence, excess salivation and excess airways secretions, tachyphylaxis, behaviour disturbance, cognitive dysfunction, hypotension, respiratory depression and apnea.
Interaction :
Alcohol, Narcotics, Barbiturates, Nonbarbiturate Hypnotics, Antianxiety Agents, the Phenothiazines, Thioxanthene and Butyrophenone Classes of Antipsychotic Agents, Monoamine Oxidase Inhibitors and the Tricyclic Antidepressants: The CNS-depressant action of the benzodiazepine class of drugs may be potentiated.
Phenytoin, Carbamazepine and Phenobarbital: Induce clonazepam metabolism, causing a decrease in plasma clonazepam levels.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Start at low dose and increase according to response |
| 10-20 | Start at low dose and increase according to response |
| <10 | Start at low dose and increase according to response |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unlikely to be dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as GFR<10 mL/min |
| CAV/VVHD | Not dialysed. Dose as in GFR=10– 20 mL/min |
Hepatic Dose :
Use with caution. Start with lower dose and adjust as per clinical response. Avoid in severe hepatic impairment.