Observations
Toxins can affect non-injected muscles
Study shows distant muscle response to Botox
A study published in the January issue of Anesthesia & Analgesia has found that botulinum toxin may have systemic effects on muscles other than those the neurotoxin has been injected into. The research team examined the immediate, delayed, local and distant effects of botulinum toxin injections.
Rats received a single botulinum toxin injection into the tibialis muscle of the hind leg. The injected muscle was completely paralysed after four days and showed decreased twitch response and muscle tension after 16 days.
The same muscle in the other hind leg showed lower twitch responses to electric stimulation, which persisted after 16 days to a lesser extent. The team saw no substantial effect on muscle function in the non-injected leg.
The study assessed changes in responses to the muscle relaxant drug Atracurium, used in patients undergoing surgery or mechanical ventilation to relax the muscles.
Muscles injected with the neurotoxin showed higher sensitivity to Atracurium, even after 16 days.
Recent botulinum toxin injections could, therefore, affect patient monitoring during surgery, as clinicians monitor muscle twitch response to evaluate atracurium’s effectiveness, reports the study.
