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Neuromuscular block by antibiotics: polymyxin B
Anesthesia and Analgesia
|May 1, 1977
Summary
Polymyxin B causes neuromuscular block in cats, with recovery taking about 72 minutes. Cholinesterase inhibitors showed limited antagonism, suggesting antibiotics uniquely affect neuromuscular junctions.
Area of Science:
- Pharmacology
- Neuroscience
Background:
- Antibiotics can cause neuromuscular blockade.
- Polymyxin B (PXB) is an antibiotic with potential neuromuscular effects.
Purpose of the Study:
- To characterize the neuromuscular block produced by Polymyxin B.
- To investigate the antagonism of PXB-induced block by cholinesterase inhibitors and calcium.
Main Methods:
- Sciatic nerve-tibialis anterior muscle preparations in anesthetized cats.
- Determination of ED50 and ED95 for PXB.
- Assessment of recovery time and train-of-four responses.
- Evaluation of antagonism by edrophonium, neostigmine, pyridostigmine, and calcium.
Main Results:
- The ED50 and ED95 of PXB were determined.
- Spontaneous recovery from block averaged 72 minutes.
- Cholinesterase inhibitors showed weak antagonism at low doses and enhancement at high doses.
- Calcium partially antagonized the neuromuscular block.
Conclusions:
- Neuromuscular blocks induced by antibiotics, like Polymyxin B, differ from those caused by other agents.
- The mechanism of PXB neuromuscular blockade is distinct and requires further investigation.
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