Anxiolytics
Mr. Harshad Khade
MSc. Medical Technology (OTA)
Symbiosis International University, Pune.
Midazolam
Class
• Short-acting benzodiazepine.
Uses
• 1. For induction of anaesthesia
• 2. For sedation during endoscopy and procedures performed under local
anaesthesia and during intensive care
• 3. As a hypnotic
• 4. For premedication prior to general anaesthesia and may be of use
• 5. In the treatment of chronic pain, including deafferentation syndromes.
Chemical A water-soluble imidazobenzodiazepine
Presentation
• As a clear, colourless solution of midazolam hydrochloride containing 1/2/5
mg/ml.
Mode of action
• Benzodiazepines are thought to act via specific benzodiazepine receptors
found at synapses throughout the CNS, but concentrated especially in the
cortex and midbrain.
• Benzodiazepine receptors are closely linked with GABA receptors and
appear to facilitate the activity of the latter.
• Activated GABA receptors open chloride ion channels which then either
hyperpolarize or short-circuit the synaptic membrane.
• Midazolam has kappa-opioid agonist activity in vitro, which may explain the
mechanism of benzodiazepine-induced spinal analgesia.
Main actions
1. Hypnosis
2. Sedation
3. Anxiolysis
4. Anterograde amnesia
5. Anticonvulsant and
6. Muscular relaxation
Routes of administration/doses
• The intramuscular dose (used for premedication) is 0.07–0.08 mg/kg; the
intravenous dose for sedation is 0.07–0.1 mg/kg, titrated according to response.
• The end point for sedation is drowsiness and slurring of speech; response to
commands is, however, maintained.
• The drug may also be administered intrathecally in an adult dose of 0.3–2 mg or
epidurally in a dose of 0.1–0.2 mg/kg.
Dose
• For sedation: 0.03-0.08 mg/kg IV
• Can also be given intramuscularly, intranasally and orally.
Onset
• Within 3-5 minutes
Duration
• Elimination half-time is 1-4 hours,
• making midazolam a much shorter acting agent than diazepam.
Elimination
• Metabolized in the liver by microsomal enzymes and excreted in the
urine.
Effects
• CNS
• Induces anxiolysis, amnesia, hypnosis.
• Decreases cerebral blood flow. Minimal effects on intracranial pressure.
• May contribute to post-operative delirium in the elderly.
• CVS
• In larger doses, in the presence of hypovolemia or when used in
combination with opioids, midazolam can lead to decreased blood
pressure and increased heart rate.
• Cardiac output is unchanged
• Respiratory
• Dose-related respiratory depression occurs.
• This response is exaggerated in the elderly, in those with COPD or when
used in combination with opioids.
• Misc.
• Midazolam is water-soluble therefore the pain on injection and phlebitis
that are seen with diazepam are uncommon.
LORAZEPAM
Uses
1. in the short-term treatment of anxiety
2. as a hypnotic
3. in premedication and
4. for the treatment of status epilepticus.
Main actions
1. Hypnosis 2. Sedation
3. Anxiolysis 4. Anterograde amnesia
5. Anticonvulsant, and 6. Muscular relaxation
Mode of action
• Benzodiazepines are thought to act via specific benzodiazepine receptors
found at synapses throughout the CNS, but concentrated especially in the
cortex and midbrain.
• Benzodiazepine receptors are closely linked with GABA receptors and
appear to facilitate the activity of the latter.
• Activated GABA receptors open chloride ion channels which then either
hyperpolarize or short-circuit the synaptic membrane.
Routes of administration/doses
• The adult oral or sublingual dose is 1–4 mg/day in divided doses.
• The intravenous or intramuscular dose is 0.025–0.05 mg/kg; intramuscular
injection is painful.
Effects
• CVS
• Lorazepam appears to have no direct cardiac effects.
• RS
• Mild respiratory depression occurs, following the administration of the
drug, which is of clinical significance only in patients with lung disease.
• CNS
• The drug produces sedation, anterograde amnesia, and an anticonvulsant
effect.
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