Muscle Twitching from 60mg Oral Atropine
Yes, a person would experience severe muscle twitching (fasciculations) after taking 60mg of atropine orally by chewing, as this represents a massive toxic overdose that would cause life-threatening nicotinic and muscarinic effects, including involuntary muscle fasciculations followed by weakness, flaccid paralysis, and likely death without immediate medical intervention.
Mechanism of Toxicity at This Dose
The 60mg dose represents approximately 30-60 times the typical therapeutic dose of atropine (1-2mg for adults). 1 At this extreme toxic level:
Nicotinic receptor effects dominate: While atropine is primarily an antimuscarinic agent, at toxic doses it produces curare-like actions at nicotinic receptors, causing involuntary fasciculations followed by muscle weakness and flaccid paralysis 2
Direct musculotropic actions: Atropine at high doses has direct effects on muscle fibers themselves, initially causing potentiation of muscle contractions (visible as twitching) before progressing to depression and paralysis 3
Expected Clinical Manifestations
Musculoskeletal Effects
- Involuntary fasciculations (muscle twitching) would occur early, affecting multiple muscle groups 2
- Progressive weakness leading to flaccid paralysis of skeletal muscles 2
- Respiratory muscle paralysis requiring mechanical ventilation 2
Central Nervous System Effects
At this toxic dose, severe CNS toxicity would occur: 1
- Restlessness and tremor
- Delirium and hallucinations
- Seizures
- Coma
- Medullary paralysis leading to death
Cardiovascular Effects
- Severe tachycardia initially 2
- Progression to circulatory collapse and hypotension 1
- Cardiac arrhythmias 2
Other Antimuscarinic Effects
- Extreme dry mouth and anhidrosis 1
- Severe hyperthermia from inability to sweat 1
- Urinary retention 1
- Paralytic ileus 1
Critical Clinical Pitfall
The muscle twitching would be an early warning sign of life-threatening toxicity, not an isolated symptom. This dose would rapidly progress to respiratory failure and death without aggressive supportive care including: 2
- Immediate airway management and mechanical ventilation
- Benzodiazepines for seizure control (midazolam 0.05-0.1 mg/kg IV or diazepam 0.2 mg/kg IV) 2, 4
- Aggressive cooling measures for hyperthermia
- Cardiovascular support for circulatory collapse
Why This Differs from Therapeutic Doses
At therapeutic doses (0.5-2mg), atropine blocks muscarinic receptors selectively without significant nicotinic effects. 2, 1 However, at 60mg, the drug overwhelms its receptor selectivity and produces: 3
- Direct toxic effects on muscle tissue
- Curare-like blockade at nicotinic receptors
- Profound CNS depression
- Multi-organ system failure
The muscle twitching would be just one component of a catastrophic, potentially fatal poisoning requiring immediate emergency medical intervention.