Postoperative pain treated by intravenous L-tryptophan: a double-blind study versus placebo in cholecystectomized patients.

The effectiveness of intravenous administration (i.v.) of L-tryptophan, which is the precursor of cerebral serotonin, was verified in the treatment of postoperative pain. The study was carried out on 45 female patients, aged between 34 and 61 years, undergoing cholecystectomy who were randomly divided into three groups. Group 1 (age: 50.33 +/- 8.64 years) received 100 ml of 5% mannitol solution i.v.; group 2 (age: 49.80 +/- 11.11 years) 100 ml of a mannitol solution containing 7.5 mg/kg L-tryptophan; and group 3 (age: 53.46 +/- 9.60 years) 100 ml of a mannitol solution containing 15 mg/kg L-tryptophan. Vital capacity (preoperative VC) was measured before surgery. Anesthesia used was isoflurane. Narcotics or neuroleptics were not used. Pain was assessed before treatment (T-0 min), at the end of administration (T-30) and at T-60, 120, 180, 240, 300 and 360 min by the following variables: respiratory rate (RR), heart rate (HR), mean arterial pressure (MAP), Scott-Huskisson test (VAS), pain vital capacity (PVC), analgesic vital capacity (AVC), and respiratory restoration factor (RRF) calculated from Bromage's formula (RRF = (AVC - PVC/preoperative VC - PVC) X 100). As regards variables RR, HR, MAP and VAS, differences between the values from T-30 to T-360 and the value at T-0 were calculated. Means and S.E.M. were calculated on the obtained values and on RRF values for each group. The significance of the differences between groups was calculated using Student's t test and Bonferroni's test. Results show a significant decrease of pain in groups 2 and 3 treated with L-tryptophan, in comparison with group 1 (controls). No significant difference was observed between the treated groups, although more lasting pain relief was observed in group 3 in comparison with group 2. Intravenous L-tryptophan showed its effectiveness in the treatment of postoperative pain even when used alone. Its use may be considered for patients with renal failure, in order to strengthen pharmacological analgesia or to prevent postoperative pain by its intraoperative administration.

The effect of benzodiazepines administration on auricular symptomatological evidence.

The aim of this study is to verify the response of auricular skin to interoceptive stimuli in two groups of patients suffering from a gastroenteral pathology. Patients were submitted to a complete examination of auricle, in order to detect morphological alterations and painful points, and to a diagnostic digestive endoscopy. A group of patients took benzodiazepines at the moment of auricular examination; the second group did not take any drug. Results show that there is a significantly lower number of auricular painful points in the patients taking benzodiazepines in comparison with the patients who did not take such drug. In the patients treated with benzodiazepines the auricular diagnosis of painful points does not seem to be reliable.