SJ

1. BENZODIAZEPINES
AND
ANTICHOLINERGICS
DR. MANOJ JAIN
UNDER GUIDANCE OF:
DR. VIKRAM BEDI SIR
DR RAJEEV SIR

2. They are widely used in anaesthesia
as
• ANXIOLYTIC
• SEDATIVE
• HYPNOTIC
BENZODIAZEPINES

3. MOA
•BZD act selectively at GABA-A( which
normally mediates fast inhibitory synaptic
transmission in CNS)
•They enhance response to GABA (gama
amino-butyric acid ) by facilitating opening
of GABA activated chloride channel ,
causing hyperpolarization, that inhibits
normal neuronal functions.

4. METABOLISM:
•BZDs are metabolized in liver.
•Metabolites are excreted in gut and
urine. There is significant enterohepatic
circulation.

5. SYSTEMIC EFFECTS
•CNS:
Mainly acts on reticular activating system (RAS)
and amygdala (limbic system) producing
sedation, anxiolysis and amnesia. They also act
on medulla producing muscle relaxation and on
cerebellum producing ataxia.

6. • BZ's are anticonvulsants.
• Produce anterograde amnesia
• They are not analgesics.
• Produce muscle relaxation by acting at
medullary and spinal cord level (central action).
• Reduces cerebral metabolic rate, brain oxygen
consumption and intracranial pressure.
• Initial regain of consciousness seen after 10-15
minutes is due to redistribution.

7. Respiratory system:
BZD depress the ventilatory response to CO2 , this effect
is seen more with i.v. use of drug and extremes of age.
Midazolam has steep dose-response curve & high potency
hence causes more respiratory depression
Cardiovascular system:
BZDs cause minor CVS depression.
Midazolam tends to reduce BP & P.V.R. more than
diazepam.

9. DIAZEPAM and LORAZEPAM:
Hardly used in intraoperative period because:
• Preparation is oil based therefore injection is
painful.
• Sleep is not smooth (incidence of dysphoria
highest with diazepam).
• Elimination half-lives are prolonged therefore
chances of postoperative respiratory depression
are there.

10.  DIAZEPAM :
Oral or I.M 5-15mg , onset is 45-90 min,
has long acting metabolites.
I.V – 0.04-0.2mg/kg for sedation & 0.3-
0.6mg/kg for induction
 LORAZEPAM :
Oral -1-2mg , onset 45 -90 min. , has
prolonged amnesic effect
I.V – 0.04-0.2mg/kg

11. MIDAZOLAM:
3 times more potent than diazepam. In current day
practice Midazolam is the only BZ used in intraoperative
period.
The advantages over diazepam and lorazepam are
• Water based preparation so injection is painless
• Elimination half-life is 2-3 hours avoiding the risk of
respiratory depression in postoperative period.
• Because of shorter half-life midazolam can be safely
used for day care procedures.
• Reversal with flumazenil is complete (no re-sedation).
• Since midazolam can be given through oral, buccal,
rectal and intranasal route (nasal spray) it can be
utilized in pediatric population

12. MIDAZOLAM :
Oral – 0.5 mg/kg(paed.) & 7.5-15 mg (adults)
Onset -15 -30 min.
– Oral route is preffered in paediatric
cases
I.M – 0.07-0.15 mg/kg
Onset -15 – 30 min.
–i.m. preparation is water soluble, non
irritating
I.V –0.01-0.1mg/kg for sedation &
0.1-0.4mg/kg for induction.
Rapid onset, excellent amnesia
Can also be given intranasal (0.2 – 0.3 mg/kg),
sublingual (0.1 mg/kg)

14. ANTICHOLINERGIC DRUGS
• Used in premed. due to their
antisecretory/antisialogogue action.
•Markedly reduce salivary secretions by blocking M3
type muscarinic receptors.
•At higher dose: they also reduce gastric secretions
by blocking M1 type muscarinic receptors.

17. • It is a tertiary amine consisting of tropic
acid & tropine.
• Crosses placental barrier & blood brain
barrier.
• When given I.M. 1 hour before anesthesia
it supresses salivary & bronchial secretions
more efficiently than given I.V. immedietly
before induction.
• C.V.S. biphasic action- initially bradycardia
by stimulating cardio-inhibitory centre in
medulla & then tachycardia due to
stimulation of S.A. node. Also has
antiarrhythmic action.
ATROPINE

18. •Resp system- decreases secretions & causes
bronchodilation.
•Antispasmodic action & lowers the tone of lower
esophageal sphincter & decreases gastric
secretion.
•Also has antiemetic action.
•Increase body temp & it is metabolised in liver.
•Overdose causes “central anticholinergic
syndrome”.

19. •Dry skin.
•Dry mouth.
•Tachycardia.
•Hot & flushed
skin.
•Agitation.
•Delirium.

20. Dose - Oral–0.03mg/kg ,I.M./ I.V.–0.01-0.02
mg/kg ( children require higher dose)

21. •It is quaternary ammonium synthetic
compound
•It doesn’t cross the placental & BBB,so
doesn’t have central anticholinergic
effects.
•It suppresses gastric secretions more than
atropine & hyoscine.
• It causes less incidence of tachycardia &
arrhythmia.
•It is effective in preventing bradycardia
after suxamethonium.
GLYCOPYRROLATE

22. It is more potent & long lasting than atropine in
reducing salivary secretions.
Like atropine & hyoscine it reduces the tone of lower
oesophageal sphincter. Thus , all anticholinergics
doesn’t reduce chances of aspiration pneumonia.
DOSE- 0.005 to 0.01 mg/kg body weight (i.m or i.v.)

23. •It is a tertiary amine.
•It is a more potent antisialogogue than
atropine & causes greater CNS effects.
Clinical dosages usually result in drowsiness ,
amnesia & residual sedation.
SCOPOLAMINE :

25. ADVERSE EFFECTS

27. Contraindications
•In constrictive pericarditis.
•Low output cardiac status eg. M.S. it reduces the
diastolic emptying time leading to pulmo.edema.
•In hypertention.
•Thyrotoxicosis/ pheochromocytoma.
•Hyperpyrexia.
•Acute angle closure glucoma.