In a double-blind investigation of the efficacy on pain following abdominal or orthopaedic surgery, meptazinol 100 mg, a new hexahydroazepine derivative, was found to be equipotent with pentazocine 60 mg and pethidine 100 mg when given i.m. Analgesia was maximal 30-60 min after injection and was still present at the end of 2 h. The duration of action of meptazinol was estimated to be 4 h. Meptazinol produced less sedation and a greater sparing of lung function tests than did pethidine and pentazocine. When meptazinol or morphine was administered for further pain relief in a single-blind manner there was no evidence of patient preference for one drug or the other.

In a single-blind study of several doses of a new hexahydroazepine analgesic, meptazinol, in 45 patients recovering from major abdominal surgery, there was a dose-related significant analgesic effect from i.m. doses exceeding 50 mg. Pain relief was maximal at the end of 1 h and the duration of effect of the 100-mg dose was approximately 5 h. There was a good correlation between pain relief assessed by the patient, by the physician, and indirectly by pulmonary function tests. Heart rate and arterial pressure were not affected by meptazionol. There were no abnormal biochemical or haematological findings and the only side-effect was vomiting in a few patients receiving multiple doses of the drug.

SUMMARY The intracellular pH of human erythrocytes in nine subjects was calculated by the DMO method and compared with direct measurements on the hemo‐lysate. The standard deviation of differences between means of duplicate observations of the two methods was ± 0.111 pH unit. The amount of DMO‐like substance in normal human blood was found to vary from one subject to another and must be taken into account in the calculations. It is concluded that the DMO method is of limited accuracy in estimating intracellular pH of human erythrocytes, but it may be useful in evaluating the extent of any changes. ZUSAMMENFASSUNG Das nach der DMO‐Methode bei 9 Versuchspersonen errechnete intracelluläre pH menschlicher Erythrozyten wurde mit direkten Messungen im Haemolysat verglichen. Die Standardabweichung der Unterschiede zwischen den Mittelwerten der beiden Methoden, die jeweils aus doppelten Beobach‐tungen stammten, betrug ± 0,111 pH‐Einheiten. Die Menge an DMO‐ähnlichen Substanzen im normalen menschlichen Blut varüerte von Fall zu Fall und musste bei den Berechnungen in Betracht gezogen werden. Die Autoren kommen zu dem Schluss, dass die DMO‐Methode bei der Schätzung des intracellulären pH menschlicher Erythrozyten nur begrenzte Genauigkeit besitzt, jedoch für die Bestimmung des Ausmasses von Veränderungen nützlich sein kann.