Yes, 30mg of oral neostigmine would cause muscle twitching
A person taking 30mg of oral neostigmine would experience muscle twitching and fasciculations due to acetylcholine accumulation at nicotinic receptors from acetylcholinesterase inhibition. 1, 2
Mechanism of Muscle Twitching
Neostigmine inhibits acetylcholinesterase, causing acetylcholine to accumulate in the synaptic cleft, which leads to excessive stimulation of nicotinic receptors and results in fasciculations (muscle twitches) 2
These fasciculations represent spontaneous depolarization of motor units at the neuromuscular junction from excess acetylcholine 1
The mechanism is identical to other acetylcholinesterase inhibitors like physostigmine and pyridostigmine 1
Clinical Evidence Supporting Muscle Twitching
Research in healthy volunteers demonstrated that even 1.0 mg per 60 kg body weight (approximately 17 mcg/kg) of intramuscular neostigmine caused fasciculations in all subjects, most profusely after 30-60 minutes, affecting an average of 6-7 muscle groups 3
Half that dose (0.5 mg per 60 kg) still provoked fasciculations in 8 out of 10 healthy subjects, affecting 2-3 muscle groups on average 3
The 30mg oral dose you're asking about is substantially higher than these research doses that reliably produced fasciculations, making muscle twitching virtually certain 3
Dose Context and Additional Effects
The standard intravenous dose for reversal of neuromuscular blockade is 40-50 mcg/kg (approximately 2.5-3.5 mg for a 70kg person), which is much lower than 30mg 2, 4
Therapeutic intravenous doses of 2.5 mg neostigmine (approximately 35 mcg/kg) in awake volunteers caused significant muscle weakness with decreased grip strength by 20%, reduced single twitch height by 14%, and restrictive spirometry patterns 5
A second dose further decreased grip strength by 41% and single twitch height by 25%, demonstrating dose-dependent neuromuscular effects 5
Expected Clinical Presentation
With 30mg oral neostigmine, expect prominent fasciculations and muscle twitching throughout multiple muscle groups, likely accompanied by other cholinergic symptoms 2, 6
Muscarinic symptoms would also occur, including nausea, vomiting, diarrhea, sweating, increased bronchial and salivary secretions, and bradycardia 6
The FDA label specifically warns that overdosage causes cholinergic crisis characterized by increasing muscle weakness through involvement of respiratory muscles 6
Critical Safety Considerations
This 30mg dose represents a significant overdose that could cause cholinergic crisis, which is potentially life-threatening 6
The FDA recommends monitoring muscle twitch response to peripheral nerve stimulation to prevent iatrogenic overdose 6
Atropine should be administered to counteract muscarinic effects, though it may mask signs of overdosage 6
Ventilatory support may be required if respiratory muscle involvement occurs 6