General Anaesthesia Pre Med Premedication refers to drugs administered before anaesthesia to facilitate induction and maintenance. These include: - Anxiolytics like benzodiazepines which produce sedation and amnesia. - Anti-emetics to reduce nausea and vomiting from opioids given before or during surgery. Common options are dopamine antagonists and antihistamines. - Antacids to ensure an empty stomach and prevent regurgitation and aspiration, achieved through starvation before surgery or drugs that increase stomach pH and reduce volume like sodium citrate, cimetidine, and metoclopramide.

1. General Anaesthesia
Pre Med

2. Premedication
Refers to those drugs administered to
facilitate the induction and maintenance of
anaesthesia
• Anxiolysis
• Amnesia
• Anti-emetic
• Antacid
• Anti-autonomic
• Analgesic

3. Premedication
Anxiolysis
Benzodiazepenes also produces sedation and amnesia
well absorbed.. Given orally 45-90 min preop
Eg Temazepam 20-30mg
Diazepam 10-20mg
Lorazepam 2-4mg.
Other agents
phenothiazenes
antihistamines
β- blockers

4. Premedication
Amnesia
Lorazepam, Midazolam provides anterograde amnesia
Anti emetic
used as premed to reduce nausea and vomiting induced
by Opioids given pre or intra op.
Dopamine antagonists Metaclopramide, Domperidone
Antihistamines cyclazine, promethazine
Anticholinergics atropine, glycopyrolate, hyoscine
Phenothiazenes promazine
5-hydroxytryptamine antagonists Ondansetron

5. Premedication
Antacid
pts to be anesthetised should have empty
stomach to prevent regurg..and aspiration.
Achieved by starvation preop. Pts on opiates,
with hiatus hernia, who are anxious, presenting
as emergency, esp. if in pain will have delayed
gastric emptying. Many drugs are used to
increase pH and reduce volume
Oral sod. Citrate
Cimetidine, ranitidine
metaclopromide

6. Premedication
Anti autonomic
inc vagal activity causing bradycardia may be
seen with
Halothane esp if used for induction
Repeated suxamethomethonium
Surgical traction on extrocular muscles
Handling of viscera
Elevation of # zygoma
• Anticholinergics like Atropine and glycopyrolate
are given at induction. It also helps in reducing
excessive secretions

7. Premedication
Sympethetic reflexes
Increased sympethetic activity can be seen at
intubation causing tachycardia and hypertension
These are undesirable in IHD and those with
raised ICP. Controlled with β-blockers or
fentanyl (analgesic) at induction
Analgesics
Given to pts who are in pain preop. Given IM
Morphine, Pethidine, Fentanyl. Opiates generally
have unwanted side effects like nausea,
vomiting, resp. deprn, delayed gastric
emptying

8. Premedication
Miscellaneous
• Steroids
• Antibiotics
• Anticoagulents as prophy against DVT
• Trans dermal GTN in pts with IHD to dec risk of
coronary ischaemia
• EMLA
• Pts own medications