3. PREMEDICATION

The anaesthetist may give drugs to the patient before surgery.

Traditionally all patients received premedication. However now, unless there is a special reason, many patients receive no premedication or only drugs to reduce anxiety, simple analgesia (e.g. paracetamol) and/or a non-particulate antacid. The change has occurred as anaesthetists have realised that premedication with narcotic analgesics (e.g. morphine or pethidine) may make patients drowsy and nauseated. Premedication with drugs that reduce airway secretions are usually not needed and make patients mouths dry and uncomfortable and premedication with drugs to prevent bradycardia (e.g. atropine) is not usually needed.

Purpose of Premedication

To provide relaxation and relieve anxiety.

To provide analgesia if the patient has pain before the operation or to provide analgesia during and after the operation.

To reduce secretions (antisialagogue) in the airway.

To reduce the risk of aspiration pneumonitis.

To prevent bradycardia due to vagal activity (vagolytic), especially in children.

Premedication Drugs

Sedatives

diazepam 0.15 mg/kg orally or intramuscularly

temazepam 0.3 mg/kg orally

midazolam 0.5 mg/kg orally (in a clear drink)

                                    (maximum of 20 mg)

ketamine 6 mg/kg orally

Analgesics

morphine 0.15 mg/kg intramuscularly

pethidine 1 mg/kg intramuscularly

Vagolytic

atropine 0.02 mg/kg intramuscularly

Aspiration prevention  

metoclopramide 0.2 mg/kg orally

sodium citrate 30 ml (0.3 mmol/litre) orally

ranitidine 150 mg orally

cimetidine 300 mg orally

Recommendation

Patients who are not in pain and not at increased risk of aspiration receive no premedication or only a sedative.

Patients at increased risk of aspiration receive histamine-2 receptor antagonist
(e.g. cimetidine or ranitidine orally) one hour preoperatively and a non-particulate antacid before surgery.

There will be some patients that will need special premedication e.g. diabetics, asthmatics and those patients taking steroid treatment or anticoagulant treatment.