Sensitivity to dimethyltubocurarine and toxiferine with special reference to serum proteins.

In a consecutive series of 100 female patients undergoing abdominal surgery muscular relaxation was obtained in half with dimethyltubocurarine and in half with toxiferine. The required dose of these relaxants (mg/m body surface) showed a lower individual variation than the requirements of any other non-depolarizing relaxants investigated under similar conditions. Neostigmine 0.5 mg reversed the block by dimethyltubocurarine better than the block by toxiferine. The requirement of dimethyltubocurarine showed no detectable correlation with any serum protein fraction. The requirement of toxiferine displayed a negative correlation with serum albumin (r=— 0.46) and only weak positive correlation with the globulins. From the present and previous studies it is concluded that charge-dissipating ethyl and allyl quaternization leads to positive correlation with albumin. Methylquaternized compounds, on the other hand, do not show this effect and may even display a negative albumin correlation as seen with toxiferine. Free phenolic hydroxyl groups induce positive correlations with the globulins while free alcoholic hydroxyl groups do not.