Atropine is an alkaloid produced by the perennial Atropa belladonna, family Solanaceae. Commonly known as belladonna or deadly nightshade. Belladonna is a small shrub that produces bell-shaped flowers and shiny round black fruit. Medically belladonna has been used since ancient times, and atropine is used by injection to treat symptomatic bradycardia, severe bronchospasm and to reduce vagal stimulation. It relaxes muscle spasms and regulates heart rate, however in it's plant form the berries and leaves are toxic to humans and can even be fatal.

Introduction to Atropine


Using Atropine

Ways of administration

Can be administered orally, intraocularly, intravenously or intramuscularly.

Effects of Atropine

Two mnemonics, which apply to all anticholinergic drugs, from professors of mine include:

"Can't spit, shit, see or pee."
"Blind as a bat, hot as a hare, dry as a bone, mad as a hatter, red as a beet."

Through its anticholinergic activity, atropine:
  • Increases heart rate
  • Dries nasal and oral mucosa, as well as other secretions throughout the body, including preventing perspiration.
  • Dilates pupils and increases intraocular pressure
  • Slows the movement of food through the gastrointestinal tract
  • Constricts smooth muscle around the urethra
  • Causes hallucinations

Combinations with Atropine

Belladonna combined with opium is still used in suppositories to control diarrhea. This is one of the few remaining examples of whole herbs used in mainstream Western medicine.

Different Uses for Atropine

Most often used for its effects on the heart, eyes, gastrointestinal tract. When administered as eyedrops, atropine causes mydriasis. The eyedrops may also be used sublingually to prevent drooling in terminally ill patients. To stop diarrhea, atropine may be taken orally or as a rectal suppository. To increase heart rate in an emergency situation, it is given intravenously.

Atropine is also used intravenously or intramuscularly as an antidote to organophosphate neurotoxins such as the insecticide Malathion and the chemical weapons VX and Sarin.

Rarely used recreationally (see below).

Pharmacology of Atropine

LD50 (mg/kg) :
Rat : 750 orally (freebase), 622 orally (sulfate monohydrate)

Chemistry of Atropine

Column 1 Column 2
Systematic (IUPAC) name: [alpha]-(hydroxylmethyl)benzeneacetic acid (3-endo)-8-methyl-8-azabicyclo[3.2.1]oct-3-yl ester
Synonyms: 1[alpha]H,5[alpha]H-tropan-3[alpha]-ol (±)-tropate (ester), dl-hyoscyamine, tropic acid ester with tropine, dl-tropine tropate, tropine tropate; Methylatropine bromide, Tropin (methylbromide); Methylatropine nitrate, Eumydrin (methylnitrate); Atropisol, Atropt (Sulfate monohydrate); atropine aminoxide, aminoxytropine tropate, genatropine (N-Oxide)
Molecular Formula: C17H27NO3
Molar mass: 289.38 g/mol, 384.31 g/mol (methylbromide), 366.41 g/mol (methylnitrate), 694.84 g/mol (sulfate monohydrate), 305.37 g/mol (N-Oxide)
CAS Registry Number: 51-55-8, 2870-71-5 (methylbromide), 52-88-0 (methylnitrate), 5908-99-6 (sulfate monohydrate), 55-48-1 (anhydrous sulfate), 4438-22-6 (N-Oxide)
Melting Point: 114-116°C, 222-223°C (methylbromide), 163°C (methylnitrate), 190-194°C (sulfate monohydrate), 127-128°C (N-Oxide)
Boiling Point: no data
Flash Point: no data
Solubility: Freebase : 1 g dissolves in 455 mL water (@ room temperature), 90 mL water (@ 80°C), 2 mL alcohol (@ room temperature), 1.2 mL alcohol (@ 60°C), 27 mL glycerol, 25 mL ether, 1 mL; soluble in benzene, dilute acids. Methylbromide : soluble in 1 part water, slightly soluble in alcohol; almost insoluble in chloroform, ether. Methylnitrate : freely soluble in water, alcohol; very slightly soluble in chloroform, ether. Sulfate monohydrate : 1 g dissolves in 0.4 mL water, 5 mL cold alcohol, 2.4 mL boiling alcohol, 2.5 mL glycerol, 420 mL chloroform, 3000 mL ether. N-Oxide : Soluble in alcohol, chloroform; practically insoluble in ether
Additionnal data: Freebase : pK 4.35, pH of 0.0015 molar solution 10.0, sublimes in ahigh vacuum at 93-110°C. Sulfate monohydrate : bitterness threshold 1/10000, pKa ~5.4. N-Oxide : decomposes at 135°C
Notes: Freebase : aspect long orthorhombic prisms from acetone. Sulfate monohydrate : very bitter; incompatible with alkalies, tannin salt of mercury or gold, vegetable decoctions or infusions, borax, bromides, iodides, benzoates. N-Oxide : very hygroscopic

The dangers of Atropine

Small amounts of the plant can quickly cause death by respiratory or cardiac failure.
Potential symptoms of overexposure include : blurred vision, suppressed salivation, vasodilatation, hyperpyrexia, excitement, agitation and delirium.

Producing Atropine

A. belladonna is native to Europe, and is hardy in U.S. zones 6-9. Needs well-drained, alkaline soil in sun or partial shade. (2)

Forms of Atropine

Legal status of Atropine

United Nations


By prescription only, not a controlled substance.


History of Atropine

Used by women in the Middle Ages to dilate pupils. "Bella donna" is Italian and translates to "beautiful woman." Used supposedly by witches in Europe for its hallucinogenic properties, and in surgery for its sedative properties before modern anesthetics.


The latest Atropine threads


1. Foster, S. and Johnson, R. L., eds. (2006) National Geographic Desk Reference to Nature's Medicine. Washington, DC: National Geographic Press.

2. Bown, D. (2001) Encyclopedia of Herbs. New York, NY: DK Publishing, Inc.

[3] Merck Index, fifteenth edition (2013)

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