[Atracurium--increased duration of its effect following alcuronium].

The duration of action of a supplementary dose of Atracurium 0.125 mg/kg after an initial dose of Atracurium 0.5 mg/kg respectively Alcuronium 0.25 mg/kg was investigated in 2 groups of 7 patients each. The average duration of action of Atracurium after Alcuronium (44.62 +/- 9.95 min) was 1.75 times longer than that of Atracurium after Atracurium (25.49 +/- 4.08 min). The difference is statistically significant (p = 0.05). For the clinical application of a combination of Atracurium with Alcuronium, 2 conclusions which might appear contradictory can be considered: 1. the pretreatment with Alcuronium can enhance intentionally the duration of action of Atracurium and spare total dosage of muscle relaxants at the same time. Prompt antagonism of muscle blockade of Atracurium remains unchanged according to our experience. 2. the pretreatment with Alcuronium may be dangerous whenever Atracurium is administered close to the end of the operation because of the possibility of prolonged postoperative muscle relaxation.