The antiemetic action of propofol.

Eighty patients who underwent minor gynaecological surgery were anaesthetised with either incremental propofol or incremental methohexitone after an opioid premedication. The group anaesthetised with propofol had significantly fewer emetic sequelae and the results suggest that propofol has a definite antiemetic action.

A comparison of propofol and methohexitone as induction agents for day case isoflurane anaesthesia.

The induction and recovery characteristics of equivalent doses of propofol and methohexitone were compared in 50 patients undergoing day case isoflurane anaesthesia. Propofol induction was smoother but was associated with greater cardiorespiratory depression. Both the speed and quality of recovery were superior with propofol compared with methohexitone.

Comparison of induction characteristics of four intravenous anaesthetic agents.

The induction characteristics of thiopentone, etomidate and methohexitone have been compared to those of propofol (2,6 di-isopropyl phenol) in unpremedicated patients. Propofol 2.5 mg/kg caused significantly more hypotension, excitatory side effects and pain on injection at the dorsum of hand than thiopentone 5 mg/kg. However, with regard to the latter two sequelae, etomidate 0.3 mg/kg and methohexitone 1.5 mg/kg caused similar or more frequent upset. Propofol 2.0 mg/kg was equipotent with thiopentone 4.0 mg/kg in terms of successful induction of anaesthesia. Hypotension may contraindicate the use of propofol in the hypovolaemic or unfit patient.

Sensitivity to propofol in the elderly.

Two studies were carried out on 609 fit, unpremedicated patients to assess the influence of patient age on the response to the rapidly-acting hindered phenol, propofol, which is being evaluated for induction of anaesthesia. In the first study, 1.25 mg/kg was injected over 20 seconds followed by 10-mg increments every 15 seconds until loss of verbal contact. This showed a great individual variation in response to the drug. A reduction in the 'induction' dose was found in elderly patients, which became marked around 60 years. In the second (340), doses ranging from 1.5-3.0 mg/kg in patients under 60 years and 1.25-2.25 mg/kg in those over 60 years were injected as a bolus over 20 seconds. Doses of 2.25-2.5 mg/kg were required to induce anaesthesia in patients under 60 years, whilst 1.5-1.75 mg/kg was adequate in those over 60 years. Side effects were more marked with the rapid injection and doses in excess of 1.75 mg/kg caused significant hypotension and apnoea in the elderly. These studies reveal marked sensitivity to propofol in the elderly with respect to both induction dose and acute toxicity.

Dose response studies with propofol ('Diprivan') in unpremedicated patients.

In younger patients, 2.25 mg/kg is a reliable induction dose of propofol, whereas this level falls to 1.5 mg/kg in older patients. The incidence of hypotension and apnoea is dose-dependent in all patients.