CHANGES IN PREMEDICANT PRESCRIPTION ARE DUE TO 1.Increasing use of day care surgery. 2.Same day admission. 3.Changes in surgical list. 4.Advances in anaesthetic agents 5.Short postoperative stays.
AIMS OF PREMEDICATION 1.Anxiolysis. 2.Analgesia. 3.Anti – emesis. 4.Antacids. 5.Anti – secretory. 6.To reduce the risk specific to the patient or type of surgery.
ANXIOLYSIS Very common. Unpleasant. Well conducted preoperative visit. Drugs sedative and cause amnesia. Timing of drug delivery. Needed in (a) particular group of patients –children (b) Certain types of surgery – cardiac.
ANTIEMESIS PONV. Effective when given intravenous at induction. Combination of agents more effective than monotherapy.
ANTACIDS. To reduce the morbidity associated with pulmonary aspiration of gastric contents. Gastric volume 25ml PH 2.5 Oral administration of clear fluids upto 2 hrs before surgery decreases gastric residual volume and acidity. Indicated in Obese Pregnant Diabetics Hiatus hernia.
ANTISECRETORY Before awake fibreoptic intubahon. Before IV ketamine anaesthesia. Prevention of vagal reflexes caused by surgical stimulation eg:- squint operations, stretching of anal sphincter.
DRUGS FOR CONTINUATION OR DISCONTINUATION IN THE PERIOPERATIVE PERIOD.
CARDIOVASCULAR DRUGS Anti – hypertensives Anti – anginal Anti – arrythmics best continued to reduce hemodynamic instability and reduce risk of MI AVOID ACE inhibitors. Angiotensin II receptor antagonists Diuretics.
ANTIBIOTICS Cardiac Lesions Prosthetic Valves Procedures associated with bacteremia for infective endocarditis prophylaxis
RESPIRATORY DRUGS To continue »Bronchodilators »inhaled ß 2 agonists
CENTRAL NERVOUS SYSTEM DRUGS Tricyclic Antidepressants –Need to be continued. –Increased risk of arrythmia and hypotension if stopped abruptly. Lithium –Potentiates non deplorazing relaxants. stopped 48-72 hrs before surgery Monoamine oxidase inhibitors –Life threatening interactions with pethidine, morphine and fentanyl –Should be discontinued 2-3 weeks before elective surgery
STEROIDS Long term steroid therapy calls for steroid replacement during anaesthesia. 10 mg prednisolone or more per day within 3 months of surgery. Minor surgery -> usual dose on the morning of surgery plus 25 mg hydrocortisone at induction. Major surgery -> usual dose on the morning of surgery plus 25mg hydrocortisone at induction. Then 25mg IV 8 th hrly for 48-72 hrs postoperatively. Resume normal preoperative dose.