Atropine: Difference between revisions
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=== Antidote === |
=== Antidote === |
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By blocking the action of acetycholine, atropine also serves as an antidote for [[organophosphate]] poisoning, particularly for [[chemical weapon]]s such as [[nerve gas]]es. Troops who are likely to be attacked with chemical weapons often carry [[autoinjector]]s with atropine which can be quickly injected into the thigh. |
By blocking the action of acetycholine, atropine also serves as an antidote for [[organophosphate]] poisoning, particularly for [[chemical weapon]]s such as [[nerve gas]]es. Troops who are likely to be attacked with chemical weapons often carry [[autoinjector]]s with atropine and [[obidoximchloride]] which can be quickly injected into the thigh. |
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=== Side effects === |
=== Side effects === |
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Revision as of 02:10, 2 October 2004
Atropine is an alkaloid extracted from the deadly nightshade (Atropa belladonna) and other plants of the family Solanaceae. It is part of the secondary metabolites of plants. It has diverse uses in medicine.
Uses
Mydriatic
The main use of atropine is in dilating the pupil (mydriasis) before undergoing eye exams, although tropicamide is now preferred due to atropine's slow degradation. Atropine-containing drops are directly applied to the eye; they perform their action because the muscles responsible for constricting the pupil use muscarinic acetylcholine receptors.
Resuscitation
Injections of atropine are used in the treatment of bradycardia (an extremely low heart rate) and pulseless electrical activity (PEA) in cardiac arrest. This works because the main action of the vagus nerve of the parasympathetic system on the heart is to slow it down. Atropine blocks that action and therefore speeds up the heart rate.
Secretions and brochoconstriction
Atropine reduces bronchial and salivary secretion (which are also directed by the parasympathetic system); a dry mouth and increased heart rate are usually among the first effects of the drug.
Antidote
By blocking the action of acetycholine, atropine also serves as an antidote for organophosphate poisoning, particularly for chemical weapons such as nerve gases. Troops who are likely to be attacked with chemical weapons often carry autoinjectors with atropine and obidoximchloride which can be quickly injected into the thigh.
Side effects
Adverse reactions to atropine include ventricular fibrillation, supraventricular or ventricular tachycardia, giddiness, nausea, blurred vision, loss of balance, dilated pupils, photophobia, and possibly, notably in the elderly, confusion, hallucinations and excitation. These latter effects are due to the fact that atropine is able to cross the blood-brain barrier. Because of the hallucinogenic properties, some have used the drug recreationally, though this is very dangerous.
Pharmacology
The most common atropine compound used in medicine is atropine sulfate (C17H23NO3)2. H2SO4 . H2O, the full chemical name is 1α H, 5α H-Tropan-3-α ol (±)-tropate(ester), sulfate monohydrate.
Atropine is a drug with a wide variety of effects. All of these derive from its blocking of the muscarinic acetylcholine receptors; acetylcholine is a neurotransmitter which transmits information from nerve cells to muscles and glands. The muscarinic acetylcholine receptor is used by the parasympathetic nervous system; atropine therefore lowers the activity of all muscles and glands that receive their stimulation via the parasympathetic system.
Toxicology
In overdoses, atropine is poisonous. Atropine is sometimes added to other potentially addictive drugs; abuse of those drugs is then prevented by the unpleasant effects of atropine overdose. The antidote to atropine itself is physostigmine or pilocarbine.
History
Atropine and its mydriatic effects were discovered by the German chemist Friedrich Ferdinand Runge (1795-1867).