II. Pharmacology

  1. Tertiary ammonium alkaloid ester of tropic acid
  2. Naturally occurs in plant sources
    1. Atropa belladonna (Deadly nightshade)
    2. Datura stramonium (Jimsonweed, Thorn apple)
  3. Described as Belladonna (beautiful woman) alkaloid
    1. Women of past used Atropine to dilate pupils
    2. Mydriasis was perceived as more attractive
  4. Related isomer to Scopolamine (hyoscine)

III. Mechanism

  1. Antimuscarinic Cholinoceptor blocking drug
  2. Causes parasympathetic blockade (parasympatholytic)
  3. Inhibits vagal nerve activity (vagolytic)
    1. Enhances Sinus node automaticity
    2. Enhances Atrioventricular Node (AV) conduction

IV. Indications

  1. Symptomatic Bradycardia associated with
    1. Poor perfusion
    2. Hypotension
  2. Relative Bradycardia
  3. Prevent vagally mediated Bradycardia with intubation
  4. Symptomatic Bradycardia with AV Block
  5. Asystole or Pulseless Electrical Activity
    1. No evidence that survival is improved with Atropine
    2. Asystole is nearly always fatal despite intervention

V. Pediatric Dosing

  1. IV Dose
    1. Dose: 0.02 mg/kg IV or IO
    2. Minimum Dose: 0.1 mg
    3. Maximum Dose
      1. Child: 0.5 mg
      2. Adolescent: 1.0 mg
  2. Endotracheal Dose
    1. Dose: 2-3x IV dose (0.06 mg/kg) diluted in 3-5cc NS
    2. Follow dose with several positive pressure breaths

VI. Adult Dosing

  1. Bradycardia
    1. Dose: 0.5-1.0 mg IV
    2. May repeat q3-5 min to max total dose of 0.04 mg/kg
  2. Asystole or Bradycardic Pulseless Electrical Activity
    1. Dose: 1 mg IV
    2. Consider giving entire 0.04 mg/kg at start)
    3. May repeat q3-5 min to max total dose of 0.04 mg/kg
  3. Endotracheal Dosing
    1. Dose: 1-2 mg per dose
    2. Dilute to 10 ml with sterile water or saline

VII. Precautions

  1. Avoid repeat dosing if possible
    1. Increases myocardial oxygen demand
    2. Atropine may provoke Ischemic Heart Disease
  2. Consider external pacing if repeat dosing needed
  3. Avoid dosing Atropine below recommended dose
    1. Causes paradoxical Bradycardia
    2. May precipitate Ventricular Fibrillation

VIII. Adverse effects

  1. Rebound Tachycardia
  2. Paradoxical Bradycardia (if low dose Atropine used)
  3. Pupil dilatation (Mydriasis)
  4. Paradoxical rate slowing
    1. Type II Second degree AV Block
    2. Third Degree AV Block
  5. Arrhythmia (especially in Coronary Artery Disease)
    1. Ventricular Fibrillation
    2. Ventricular Tachycardia
  6. Anticholinergic Toxicity with overdosage
  7. Decreased Sweating and secretions
  8. Mild sedation to Delirium

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Related Studies

Cost: Medications

atropine (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
ATROPINE 1% EYE DROPS Generic $11.84 per ml
ATROPINE 1% EYE OINTMENT Generic $4.33 per gram
hyoscyamine (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing)
HYOSCYAMINE 0.125 MG ODT Generic $0.24 each
HYOSCYAMINE 0.125 MG TAB SL Generic $0.23 each
HYOSCYAMINE 0.125 MG/5 ML ELIX Generic $0.05 per ml
HYOSCYAMINE 0.125 MG/ML DROP Generic $0.88 per ml
HYOSCYAMINE SULF 0.125 MG TAB Generic $0.26 each

Ontology: Atropine (C0004259)

Definition (MSH) An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
Definition (NCI) A synthetically-derived form of the endogenous alkaloid isolated from the plant Atropa belladonna. Atropine functions as a sympathetic, competitive antagonist of muscarinic cholinergic receptors, thereby abolishing the effects of parasympathetic stimulation. This agent may induce tachycardia, inhibit secretions, and relax smooth muscles. (NCI04)
Definition (CSP) anticholinergic alkaloid originally from Atropa belladonna; used as an antispasmodic to relax smooth muscles, to increase heart rate by blocking the vagus nerve, as an antidote for various toxic and anticholinesterase agents, and as an antisecretory, mydriatic, and cycloplegic.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D001285
SnomedCT 372832002, 73949004
LNC LP14891-3, MTHU002117
English Atropine, dl-Hyoscyamine, Benzeneacetic acid, alpha-(hydroxymethyl)- 8-methyl-8-azabicyclo(3.2.1)oct-3-yl ester endo-(+-)-, dl-Tropyl Tropate, endo-(+/-)-alpha-(Hydroxymethyl)benzeneacetic Acid 8-methyl-8-azabicyclo[3.2.1]oct-3-yl Ester, atropine (medication), Atropine [Chemical/Ingredient], ATROPINE, atropine [chemical substance], atropine, Daturine, Dl-hyoscyamine, Atropine (product), Atropine (substance), Hyoscyamine (dl-)
Swedish Atropin
Czech atropin
Finnish Atropiini
Japanese ヒオスシアミン, アトロピン
Polish Atropina
Spanish DI-hiosciamina, atropina (producto), atropina (sustancia), atropina, daturina, Atropina
French Atropine
German Atropin
Italian Atropina
Portuguese Atropina

Ontology: Hyoscyamine (C0596004)

Definition (MSH) The 3(S)-endo isomer of atropine.
Definition (NCI) A belladonna alkaloid derivative and the levorotatory form of racemic atropine isolated from the plants Hyoscyamus niger or Atropa belladonna, which exhibits anticholinergic activity. Hyoscyamine functions as a non-selective, competitive antagonist of muscarinic receptors, thereby inhibiting the parasympathetic activities of acetylcholine on the salivary, bronchial, and sweat glands, as well as the eye, heart, bladder, and gastrointestinal tract. These inhibitory effects cause a decrease in saliva, bronchial mucus, gastric juices, and sweat. Furthermore, its inhibitory action on smooth muscle prevents bladder contraction and decreases gastrointestinal motility.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D064692
SnomedCT 372757002, 40851005, 48899009
LNC LP15172-7, MTHU002561
English hyoscyamine, Duboisine, urological antispasmodics hyoscyamine, hyoscyamine (medication), l-hyoscyamine, (-)-Atropine, Benzeneacetic acid, alpha-(hydroxymethyl)-, 8-methyl-8-azabicyclo(3.2.1)oct-3-yl ester, (3(S)-endo)-, (S)-Atropine, HYOSCYAMINE, Atropine, 3(S)-endo-Isomer, Duboisine (substance), Hyoscyamine [Chemical/Ingredient], L-hyoscyamine, Hyoscyamine (product), Hyoscyamine (substance), Hyoscyamine
Spanish duboisina, duboisina (sustancia), L-hiosciamina, hiosciamina (producto), hiosciamina (sustancia), hiosciamina
Czech levo-atropin, levotočivý izomer atropinu, hyoscyamin
French Hyoscyamine
German Hyoscyamin
Italian Iosciamina