Lorazepam
Mechanism :
Lorazepam is a benzodiazepine. Benzodiazepines presumably exert their effects by binding at stereo specific receptors at several sites within the central nervous system. All benzodiazepines cause a dose-related central nervous system depressant activity.
Indication :
- Anxiety
- Psychosomatic Disorders
- Premedication
- Insomnia due to anxiety
- Acute panic attacks
- Status epilepticus
Contraindications :
Lorazepam is contraindicated in patients with hypersensitivity to benzodiazepines or to any components of the formulation, in acute narrow-angle glaucoma, pre-existing CNS depression, coma, acute pulmonary insufficiency or sleep apnea. Encephalopathy may be precipitated in patients with severe hepatic insufficiency.
Dosing :
Anxiety/sedation:
Children:
0.05-0.1 mg/kg/dose orally 4-8 hourly. Max: 2 mg/dose.
Status epilepticus:
Children:
0.05-0.1 mg/kg over 2-5 min and if required repeat every 10-15 min as needed. Max dose: 4 mg OR,
0.1 mg/kg at slow IV, max rate of 2 mg/min. Max dose: 4 mg.
Adolescent:
4 mg slow IV, if seizure persists may repeat after 10-15 min.
Adverse Effect :
The common side effects seen are drowsiness, ataxia, irritability, light-headedness, dysarthria and disinhibition. Occasionally, confusion, hangover, headache, dizziness, blurred vision, depression and hallucinations have been seen. Withdrawal symptoms on long term usage: Muscle cramps, tremor, irritability, convulsions and perceptual distortions.
Interaction :
CNS depressants - Anaesthetics, Opioids, Antihistamines, Baclofen, Barbiturates, Antipsychotics, Anxiolytics, Antidepressants: Enhanced effectiveness.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
20-50 | Dose as in normal renal function |
10-20 | Dose as in normal renal function |
<10 | Dose as in normal renal function |
Dose in Patients undergoing Renal Replacement Therapies
CAPD | Unlikely dialysability. Dose as in normal renal function |
HD | Not dialysed. Dose as in normal renal function |
HDF/High flux | Unknown dialysability. Dose as in normal renal function |
CAV/VVHD | Not dialysed. Dose as in normal renal function |
Hepatic Dose :
Dose may be reduced as per clinical response. Since the drug is metabolized into its inactive form by liver, hepatic impairment can lead to high levels of drug in the body.