Double blind study of phenothiazines used in pre-anaesthetig medication: A clinical evaluation of promethazine (phenergan®), promazine (sparine®), proclorperazine (stemetil®), and levomepromazine (nozinan®)

Abstract

Pre-anaesthetic medication with promethazine, promazine, proclorperazihe, and levomepromazine was studied under controlled clinical conditions employing the double blind method with a placebo, and a known standard. The test drugs were combined with secobarbital and administered by mouth the night before an elective operation to determine their effectiveness for inducing undisturbed sleep. Approximately one hour before induction of anaesthesia, each patient received an intramuscular injection of the same test drug, combined with scopolamine in the blind study or promethazine with atropine in the standard study. Data were collected on a special protocol. This contained information recorded from the initial visit, before induction of anaesthesia, in the postanaesthetic recovery room, and 24 hours postoperatively. On completion of the study, these data were tabulated and analysed befare revealing the code. Analysis of the data showed whether the administered drugs disturbed the vital signs, allayed apprehension, induced light sleep or caused amnesia. The data from each series of drug tests were compared. In this study, levomepromazine was the most effective premedicant without causing any more undesirable effects than were seen among the others. It appears as if the "price" we pay for tranquillity should depend partly on the pharmaceutical industry and on the-skill exercised by the anaesthetists who use their drugs, just as it does for our primary anaesthetics. The greatest value from individual drugs-whether they are narcotics, barbiturates, phenothiazines, or other ataractics-will depend ultimately on the ability of the individual anaesthetist to prepare the patient by his own personal approach, and by his considered and experienced selection from a wide range of drugs. The greatest emphasis should be placed on the individual selection of a drug in relation to the age, size, temperament and physical state of the patient. © 1960 Canadian Anesthesiologists.