Preanaesthetic medication basic review. Yeasr of making 2015.

1. PREANAESTHETIC
MEDICATION
By:
Himani Manju Malhotra
2nd MBBS
Roll no: 52

2. • What are pre-anaesthetic drugs?
• Why are pre-anaesthetic drugs given?
• What are the drugs which
are included in pre-anaesthetic
medication?
• When are these drugs given?

3. WHAT & WHY
Preanaesthetic medication refers to the use of drug
before anaesthesia to make it more pleasant & safe.
The aims are:
1) To relieve anxiety.
2) To provide haemodynamic stability.
3) To induce sedation & reduce metabolic rate.
4) To provide analgesia and amnesia.
5) To decrease the chances of aspiration.
6) To control oral &respiratory secretions.
7) To prevent postoperative nausea and vomiting.
8) To control infection.

4. PREANAESTHETIC MEDICATION
• Benzodiaze-pines like diazepam(5-10mg) &
lorazepam(2mg oral or 0.05 mg/kg i.m. 1hour
before), produce tranquility & smoothen
induction. Diazepam is also centrally acting
skeletal muscle relaxant.
• There is loss of recall of perioperative events
with little respiratory depression or post
operative vomiting. They counteract CNS
toxicity of local anaesthetics & are being used
along with pethidine/fentanyl for minor
surgical and endoscopical procedures.
1-SEDATIVE-ANTIANXIETY DRUGS

5. 2-OPIOIDS-TO PROVIDE ANALGESIA
• Earlier morphine was given, it showed disadvantage of-
i. Respiratory depressant
ii. Causes peripheral vasodilatation responsible for
hypertension.
iii. Shows anti-diuretic action.
iv. Causes meiosis.
• Use of opioids is now mostly restricted to those having
preoperative pain. When indicated, fentanyl is mostly
injected i.v. just before induction.
• Given i.v. just before induction or i.m. 1 hour before
surgery.

6. 3-ANTICHOLINERGICS
• Earlier Atropine was used, which is now replaced
by Glycopyrolate.
Atropine showed the following advantages-
i. Atropine prevents vasovagal shock.
ii. It causes drying up of secretions making
intubation easy.
iii. It increases heart rate.
However, it showed CNS effects due to which it was
replaced by Glycopyrolate.

7. ACTION ATROPINE GLYCOPY
-ROLATE
1-Antisecetory ++ +++
2-Tachcardia +++ ++
3-CNS effects + -
4-Bronchodilatation ++ ++

8. 4-H2 BLOCKERS/PROTON PUMP
INHIBITORS
• Rantidine(150mg) or omeprazole(20mg) or
famotidine(20mg) are given night before and
in the morning. They benefit by raising the pH
of gastric juice & may also reduce its volume &
thus chances of regurgitation. The chances of
reflux & damage to lungs on aspiration
(Mendelson’s syndrome) is minimal if volume
of gastric juice is <25ml & pH is >3.5.
prevention of stress ulcers is another
advantage.

9. 5-ANTIEMETICS
• Ondensetron (4-8mg) i.v. is selective 5-HT3
blocker has been found highly effective in
reducing the incidence of post-anaesthetic
nausea & vomiting. It is practically devoid of
side-effects & has become antiemetic of
choice in anaesthetic practice.

10. 6-TO CONTROL INFECTIONS
• The timing of antibiotic should be adjusted so
that peak blood kevels are achieved at the
time of skin incision. Mostly, antibiotic is given
i.v. 5-10 minutes before incision. If given orally,
should be given 1-2 hours before the surgery.

11. 7-TO DECREASE CHANCES OF
ASPIRATION
Patient should be fasting for 8 hours for solid
food & 3-4hours for clear fluids. Clear juices
only inc water and juice without pulp, tea
coffee are considered as unclear fluids so full
fasting of 8 hours is needed.
FOR CHILDREN- 6-8 hours for solid food & 2-3
hours for clear fluids is sufficient.
FOR INFANTS(on milk)-fasting for 4 hours for
milk & 2hours for water is sufficient.

12. THANKYOU!