Pre-anaesthetic medication refers to drugs administered before anesthesia to improve safety and patient experience. These drugs can relieve anxiety, cause amnesia, potentiate the effects of anesthetics, decrease secretions, reduce nausea and vomiting, and decrease gastric acid. Common pre-anesthetic medications include benzodiazepines for anxiety relief, opioids for analgesia, anticholinergics to reduce secretions, neuroleptics for anxiety and nausea relief, and proton pump inhibitors or H2 blockers to reduce gastric acid and risk of aspiration. The goals of pre-anesthetic medication are to provide patient comfort before and after surgery and to create optimal conditions for safe and effective anesthesia administration.
3. 1. Relief of anxiety and apprehension Preoperatively and to facilitate
smooth induction.
2. Amnesia for pre- and postoperative events.
3. Supplement analgesic action of anaesthetics and potentiate them so
that less anaesthetic is needed.
4. Decrease secretions and vagal stimulation that may be caused by the
anaesthetic.
5. Antiemetic effect extending to the postoperative period.
6. Decrease acidity and volume of gastric juice so that it is less
damaging if aspirated. Different drugs achieve
The aims of pre-anesthetic medications are:
4. ? Different drugs achieve Different purposes. One or more drugs may be
used in a patient depending on the needs.
? Different drugs achieve different purposes. One or more drugs may be
used in a patient depending on the needs.
5. 1. Sedative-antianxiety drugs
Benzodiazepines like diazepam (5¨C10 mg oral) or lorazepam (2 mg
oral or 0.05 mg/kg i.m. 1 hour before) have become popular drugs for
preanaesthetic medication because they produce tranquility and
smoothen induction;
6. 2. Opioids
Morphine (10 mg) or pethidine (50¨C100 mg), i.m. allay anxiety and
apprehension of the operation, produce pre- and postoperative
analgesia, smoothen induction, reduce the dose of anaesthetic
required and supplement poor analgesics (thiopentone, halothane) or
weak anaesthetics (N2O). Postoperative restlessness is also reduced.
7. 3. Anticholinergics
Atropine or hyoscine (0.6 mg or 10¨C20 ¦Ìg/kg i.m./i.v.) or
glycopyrrolate (0.2¨C0.3 mg or 5¨C10 ¦Ìg/kg i.m./ i.v.) have been used,
primarily to reduce salivary and bronchial secretions.
8. 4. Neuroleptics
Chlorpromazine (25 mg), triflupromazine (10
mg) or haloperidol (2¨C4 mg) i.m. are
infrequently used in premedication. They allay
anxiety, smoothen induction and have
antiemetic action.
9. 5. H2 blockers/proton pump
inhibitors
? Patients undergoing prolonged operations, caesarian section and
obese patients are at increased risk of gastric regurgitation and
aspiration pneumonia.
? Ranitidine (150 mg)/famotidine (20 mg) or omeprazole (20
mg)/pantoprazole (40 mg) given night before and in the morning
benefit by raising pH of gastric juice and may also reduce its volume
and thus chances of regurgitation.
? The chances of reflux and damage to lungs on aspiration is minimal if
volume of gastric juice is <25 ml and pH is >3.5.
? Prevention of stress ulcers is another advantage. They are now
routinely used before prolonged surgery.
10. 6. Antiemetics
? Metoclopramide 10¨C20 mg i.m. preoperatively is effective in reducing
postoperative vomiting
? Domperidone is nearly as effective and does not produce
extrapyramidal side effects.
? Ondansetron (4¨C8 mg i.v.) the selective 5-HT3blocker has been found
highly effective in reducing the incidence of post-anaesthetic nausea
and vomiting