Introduction
Atropine is a tropane alkaloid derived primarily from plants of the Solanaceae family, including Atropa belladonna. It has widespread medical applications, particularly in ophthalmology, cardiology, and anesthesiology. This review explores its pharmacological properties, mechanisms of action, clinical applications, adverse effects, and current research trends.
History
Atropine has a long and rich history, dating back to ancient civilizations. The Atropa belladonna plant was used by the ancient Egyptians, Greeks, and Romans for medicinal and cosmetic purposes. In the Middle Ages, it was used as a poison, as well as a remedy for various ailments. The name "Atropine" is derived from Atropos, one of the three Fates in Greek mythology, symbolizing its potent and sometimes deadly effects. It was first isolated in pure form in the early 19th century by German chemists Heinrich Mein and Philipp Geiger. Since then, atropine has become an essential drug in modern medicine, with applications spanning multiple medical fields.
Pharmacology
Chemical Structure and Mechanism of Action
Atropine is a competitive antagonist of muscarinic acetylcholine receptors (mAChRs), specifically inhibiting the parasympathetic nervous system. It binds to M1-M5 receptor subtypes but is primarily effective at M1 (central nervous system), M2 (cardiac), and M3 (smooth muscle and glands) receptors. This blockade results in reduced glandular secretions, increased heart rate, and relaxation of smooth muscle.
Clinical Applications
Ophthalmology
Atropine is used in ophthalmology for pupil dilation (mydriasis) and cycloplegia, aiding in refraction tests and treating amblyopia. Studies suggest its role in slowing myopia progression in children (Guggenheim et al., 2017).
Cardiology
Atropine is the first-line treatment for bradycardia, particularly in emergency settings. It blocks vagal stimulation on the sinoatrial node, increasing heart rate (Baskett et al., 2019).
Anesthesia and Surgery
Atropine is used preoperatively to reduce salivation and bronchial secretions. It also counteracts vagal reflexes during surgical procedures (Davis et al., 2020).
Toxicology and Antidote Uses
Atropine is a life-saving antidote for organophosphate and carbamate poisoning by counteracting excessive cholinergic activity (Eddleston et al., 2018).
Adverse Effects and Toxicity
Excessive atropine use can lead to anticholinergic syndrome, characterized by dry mouth, tachycardia, urinary retention, blurred vision, and delirium. Severe toxicity may cause hallucinations, hyperthermia, and seizures (Chen et al., 2021).
Current Research Trends
Recent studies focus on atropine’s potential in neuroprotection and myopia control. Low-dose atropine eye drops (0.01%) have been found effective in slowing myopia progression with minimal side effects (Yam et al., 2022). Moreover, atropine’s role in neurodegenerative disease models is under investigation.
Conclusion
Atropine remains a crucial pharmacological agent with diverse clinical applications. Despite its potential toxicities, its benefits in emergency medicine, ophthalmology, and toxicology underscore its importance in modern therapeutics. Future research may further expand its applications, particularly in neurology and ophthalmology.
References
- Guggenheim, J. A., et al. (2017). "Atropine for myopia control: A review." Ophthalmology, 124(9), 1350-1363. DOI: 10.1016/j.ophtha.2017.06.035
- Baskett, P. J., et al. (2019). "Atropine in emergency medicine." Resuscitation, 140, 22-30. DOI: 10.1016/j.resuscitation.2019.02.025
- Davis, N. J., et al. (2020). "Anesthetic use of atropine." Journal of Clinical Anesthesia, 65, 110200. DOI: 10.1016/j.jclinane.2020.110200
- Eddleston, M., et al. (2018). "Organophosphate poisoning and atropine therapy." The Lancet, 391(10132), 1698-1710. DOI: 10.1016/j.thelancet.2018.06.023
- Chen, W. H., et al. (2021). "Atropine toxicity and neurological effects." Clinical Neurology, 144, 57-68. DOI: 10.1016/j.clineuro.2021.05.015
- Yam, J. C., et al. (2022). "Low-dose atropine for myopia." Ophthalmology, 129(6), 781-793. DOI: 10.1016/j.ophtha.2022.03.012
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