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British Journal of Clinical Pharmacology logoLink to British Journal of Clinical Pharmacology
. 1974 Jun;1(3):217–222. doi: 10.1111/j.1365-2125.1974.tb00239.x

Preliminary assessment of RX 72601, a new anticholinesterase in man

Reversal of competitive neuromuscular blockade

P W Dettmar, G Metcalf, M H Smith, G B Gillett, Annmarie Hedges, A Richens
PMCID: PMC1402557  PMID: 22454950

Abstract

1 The effect of RX 72601, neostigmine plus atropine, or saline on neuromuscular blockade with (+)-tubocurarine was studied in a double blind trial in four healthy male volunteers.

2 The methods used to assess neuromuscular function were voluntary grip strength and indirectly evoked muscle twitches. The muscarinic action was assessed by measuring intestinal motility with a pressure sensitive radio pill, and auscultation of the abdomen. Blood pressure and pulse rate were also recorded. The degree of acetylcholinesterase inhibition achieved in whole blood was determined before and at intervals after the administration of the anticholinesterases.

3 Both RX 72601 (0.66-0.83 mg) and neostigmine (2.5 mg) completely reversed the neuromuscular blockade produced by tubocurarine, but the time course of reversal differed. RX 72601 (0.66-0.83 mg) produced similar inhibition of acetylcholinesterase in whole blood to neostigmine (2.5 mg). The doses of RX 72601 used caused minimal stimulation at muscarinic sites as evidenced by the limited effect on pulse rate and intestinal activity.

4 It was concluded that RX 72601 could be safely used to reverse the effects of neuromuscular blockade without the need for premedication with atropine.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Doxey J. C., Metcalf G., Smith M. H., Whittle B. A. Some pharmacological properties of RX 67668--a new anticholinesterase. Br J Pharmacol. 1972 Nov;46(3):568P–569P. [PMC free article] [PubMed] [Google Scholar]
  2. Gillett G. B., Hedges A., Metcalf G., Richens A., Royds R. B. Reversal of competitive neuromuscular blockade by RX 67668 in normal volunteers. Br J Pharmacol. 1972 Nov;46(3):581P–582P. [PMC free article] [PubMed] [Google Scholar]

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