Correspondence

New Neuromuscular Blocking Drugs

N Engl J Med 1995; 333:1155October 26, 1995

Article

To the Editor:

We congratulate Dr. Hunter (June 22 issue)1 on her timely review. It must be emphasized, however, that neuromuscular blocking drugs should be used only by practitioners who are skilled in airway management and respiratory support, and only after sufficient sedation and analgesia have been provided to patients, since these drugs are intrinsically devoid of any sedative, analgesic, or amnestic properties.2

To Hunter's description of the ideal neuromuscular blocking drug we would add that it should not interact with other drugs. Drugs known to potentiate the action of neuromuscular blockers include inhaled anesthetic agents, antibiotics (especially aminoglycosides), antiarrhythmic drugs, beta-adrenergic–antagonist drugs, diuretic agents, lithium, cyclosporine A, dantrolene, and cyclophosphamide.

Neuromuscular blocking drugs are given for prolonged periods to up to 5 percent of critically ill patients. Most of the current recommendations regarding the use of these drugs in intensive care units are extrapolated from short-term studies in relatively healthy patients undergoing surgery.2 This may explain the reports of prolonged weakness after long-term (>24-hour) use of neuromuscular blocking drugs in critically ill patients. Several of these drugs (e.g., vecuronium and pancuronium) are metabolized to active desacetyl metabolites, and their accumulation is well documented.3 In critically ill patients with creatinine clearance values of <50 ml per minute, the recovery time was prolonged after the administration of pancuronium but not doxacurium.4 Similarly, recovery after infusions of vecuronium was slower than after infusions of cisatracurium.5 Prolonged recovery may be related to effects of the blocking drug that are pharmacologic (drug overdoses or accumulations of active metabolites), physiologic (changes in the neuromuscular junction with critical illness), or potentially toxic (effects that are secondary to drug–drug interactions or to drug–muscle or drug–nerve interactions).

Douglas B. Coursin, M.D.
University of Wisconsin Clinical Science Center, Madison, WI 53792-3272

Richard C. Prielipp, M.D.
Bowman Gray School of Medicine, Winston-Salem, NC 27159-1009

Michael J. Murray, M.D., Ph.D.
Mayo Clinic, Rochester, MN 55902

5 References

1. 1

   Hunter JM. New neuromuscular blocking drugs. N Engl J Med 1995;332:1691-1699
   Full Text | Web of Science | Medline

2. 2

   Coursin DB, Prielipp RC. Use of neuromuscular blocking drugs in the critically ill patient. Crit Care Clin 1995;11:957-981
   Web of Science | Medline

3. 3

   Caldwell JE, Szenohradszky J, Segredo V, et al. The pharmacodynamics and pharmacokinetics of the metabolite 3-desacetylvecuronium (ORG 7268) and its parent compound, vecuronium, in human volunteers. J Pharmacol Exp Ther 1994;270:1216-1222
   Web of Science | Medline

4. 4

   Murray MJ, Coursin DB, Scuderi PE, et al. Double-blind, randomized, multicenter study of doxacurium vs. pancuronium in intensive care unit patients who require neuromuscular-blocking agents. Crit Care Med 1995;23:450-458
   CrossRef | Web of Science | Medline

5. 5

   Prielipp RC, Coursin DB, Scuderi PE, et al. Comparison of the infusion requirements and recovery profiles of vecuronium and cisatracurium 51W89 in intensive care unit patients. Anesth Analg 1995;81:3-12
   CrossRef | Web of Science | Medline