1.
PRE-ANESTHETIC MEDICATION
Uses
It is the use of drugs prior to anesthesia to make it more
safe and pleasant.
• To decrease anxiety
• To increase effectiveness of an incomplete anesthetic
• To reduce the amount of anesthetic needed
• To prevent undesirable actions of anesthetics such as
salivation, bradycardia and post anesthetic vomiting
• To facilitate smooth and rapid induction and recovery
• To relieve pre- and post-operative pain

2.
Classification
• A. Anticholinergics (atropine, scopolamine,
glycopyrrolate)
• B. Tranquilizers (phenothiazine, rauwolfia,
propanediol, butyrophenone, benzodiazepine,
thioxanthine)
• C. Hypnotics and Sedatives (Barbiturates, chloral
hydrate, bromides, paraldehyde)
• D. Analgesics: Narcotics (morphine, codeine,
thebaine, and synthetics) and Non-narcotics:-
salicylates, pyrazolone, indomethacin, xylazine
• E. Neuroleptanalgesics: Domperidol/fentanyl;
Etorphine/acepromazine.

3.
Anticholinergics (Atropine)
• Source: Atropa belladona
• Mechanism: blocks muscarinic receptors of Ach
• Pharmacologic effects: Decrease GI secretions and
motility, bronchodilatation, tachycardia, mydriasis,
relax urinary tract
Indications and effects
To reduce salivary and tear secretions
Promotes bronchodilation
Blocks the stimulation of the vagus nerve preventing
bradycardia and reduced cardiac output
 Dilate pupils (mydriatic)
Reduces gastrointestinal activity (anti-emetic) by
inhibiting peristalsis, & Amnesia

4.
Glycopyrrolate
(Rubinul-V)
• A quaternary ammonium, does not pass blood brain barrier
• Atropine & scopolamine are tertiary;pass through BBB
• Peak effects within 30-45 min after i.m. injection
• Inhibits muscarinic receptors, limited effect in ganglia.
• Reduces volume and acidity of stomach
• Controls excessive pharyngeal, tracheal and bronchial
secretions.
• Antagonizes bronchospasm, bronchorrhea, intestinal
hypermotility, bradycardia.
•Glycopyrrolate has a slower onset of action and
generally has less potential for producing a
tachycardia or cardiac arrhythmia
•Atropine is more potent and faster acting
•Salivation is more effectively suppressed with
glycopyrrolate

5.
Anticholinergics (Parasympatholytics)
Contraindications
•Tachycardiac patients
•Possibly with geriatrics or with other conditions
such as congestive heart failure that could not
handle a potential tachycardia
•Condition such as constipation which would
further reduce peristaltic action of the intestine
(i.e. endoscopic procedures)
Disadvantages
•Delays recovery, Delirium, Disorientation, Dryness of
mouth

6.
Tranquilizers
Pharmacological effects
• Mechanism: Decrease motor activity, causes mental
calming, increases threshold to external stimuli
• Advantages:easy handling, reduces anesthetic dose,
inhibits vomiting in anesthesia, smooth recovery
• Disadvantage: not a true analgesics, expensive, alpha
blockade (hypotension), Delays recovery, respiratory
depression, involuntary movements/muscle dystonias
E.g: Chlorpromazine; 25mg, Triflupromazine;10mg
Haloperidol; 2-4mg

7.
 Phenothiazines
◦ Contraindications
Convulsing/epileptic patients,
seizure history or head trauma
 Hypotension
Depressed patients
Caution with geriatrics and
pediatrics; use a lower dose or
consider alternative agents such as
benzodiazepines
Liver or kidney disease

8.
 Benzodiazepines (Benzodiazepines)
◦ MOA: Potentiation of GABA-A
◦ Indications
 Patients with a history of seizure
 Minimal cardiovascular or respiratory depression
 Useful in geriatric or pediatric
 Ideal for older, depressed or anxious patients
 Works effectively as an induction agent when used
with ketamine
Contraindications
May cause excitement in some patients
Neonates and patients with poor hepatic function
Effects are reversed with flumazenil if adverse
effects are seen

9.
 Opioids
◦ Commonly used:
 Morphine
 Oxymorphone (Numorphan)
 Butorphanol (Torbugesic, Torbutrol)
 Hydromorphone
 Meperidine (Demerol, Pethidine)
 Fentanyl
Act by reversible combination with one or more
specific receptors in the brain and spinal column
 Produces a variety of effects
 Analgesia
 Sedation
 Euphoria
 excitement

10.
 Opioids
Adv
◦ Commonly used as an analgesic in premedication, as an
induction agent or can be used for balanced anesthesia and
post-operative pain control
 Provides some sedation and may potentiate the action of the
sedative that it is given with, Cough suppression
 Disadv
Respiratory depression is dose dependent
Gastrointestinal effects depend on the agent
May initially include diarrhea, vomiting and flatulence
Constipation may occur as a result of prolonged GI stasis
Addiction
Body temperature decreases due to a resetting of the
thermoregulatory center in the brain
Miosis – pin point pupil
Increased responsiveness to noise
Excessive salivation, Sweating

11.
Contraindications
Previous history of opioid
excitement
Morphine has a higher incidence
of producing vomiting so should be
avoided in cases of GI obstruction
and diaphragmatic hernia

12.
 Neuroleptanalgesics
◦ Any combination of an analgesic and
a tranquilizer (i.e. oxymorphone and
acepromazine)
◦ Indications
Heavier sedation (depending on
dose) for short procedures (i.e.
wound suturing)
Cardiac or shock cases