Scopolamine

(9-methyl-3-oxa-9-azatricyclo[3.3.1.0²,⁴]nonan-7-yl) 3-hydroxy-2-phenylpropanoate

Overview

Scopolamine belongs to Deliriants.

Key safety note: Scopolamine is safe and effective at the low doses used for motion sickness and nausea, but it has a narrow margin and is dangerous in overdose.[6][7]
Effects
Subjective effects vary. What a substance feels like depends on dose, individual physiology, mindset, and setting. The points below describe commonly reported effects, not guaranteed, uniform, or desirable outcomes.
  • At therapeutic (antiemetic / anti-motion-sickness) doses: prevention of nausea and vertigo, together with anticholinergic side effects: dry mouth, blurred vision, drowsiness, dilated pupils and a faster heartbeat.
  • It is amnestic and sedating rather than euphoric. People who take it seeking psychoactivity typically report a dysphoric, confusing and frightening experience.
  • At high or toxic doses: a deliriant syndrome: vivid hallucinations experienced as real, disorientation, agitation, memory loss, flushed dry skin, urinary retention, hyperthermia and, in severe cases, seizures, arrhythmia and coma.
Dosing & duration
Harm-reduction note: These are commonly cited reference ranges, not a recommendation or a “safe” dose. Potency, purity, body chemistry, tolerance, and drug combinations vary widely. Start low, go slow, wait for full effects before redosing, and never assume an unknown product matches these figures. Missing data is not evidence of safety.

Transdermal patch, oral, sublingual, subcutaneous, intravenous, intramuscular and ophthalmic. The transdermal patch is the usual route for motion sickness.. Scopolamine is a prescription antimuscarinic used at low doses. The figures below are therapeutic references, not recreational guidance. It is a deliriant at higher doses, not a euphoriant: anticholinergic delirium is unpleasant and dangerous (hyperthermia, seizures, arrhythmia, coma). The therapeutic window is narrow and effects are unpredictable between individuals, so there is no safe recreational dose. Combining it with other anticholinergics (many antihistamines, tricyclics, antipsychotics) compounds the toxicity.

Dose ranges

Motion sickness (transdermal)

1.5 mg patch over 72 h

Antiemetic / antisecretory (parenteral)

0.3–0.6 mg SC/IM/IV

Toxic / deliriant range

Supra-therapeutic, unpredictable and dangerous

Duration

onset

Transdermal ≈6–8 h to full effect, parenteral within ~30 min

total

Transdermal patch up to ~72 h, a single parenteral dose lasts several hours

after effects

Residual anticholinergic effects and amnesia. Blurred vision may persist

Chemical & Physical Properties
FormulaC17H21NO4
Molar mass303.35 g/mol
StateSolid (usually the hydrobromide salt, white crystalline powder, free base is a viscous, low-melting solid)
Melting point≈59 °C (free base), ≈195 °C (hydrobromide)
Boiling pointNot reported
DensityNot reported
Vapor pressureNot reported
pKa≈7.5–7.8 (tertiary amine)
LogP0.9 (predicted, XLogP3)
SolubilityHydrobromide: freely soluble in water, soluble in ethanol, Free base: soluble in water, ethanol, ether and chloroform
Refractive indexNot reported
Identifiers & Synonyms
CAS51-34-3
CAS (enantiomer)
PubChem CID5184
InChIKeySTECJAGHUSJQJN-UHFFFAOYSA-N
InChIInChI=1S/C17H21NO4/c1-18-13-7-11(8-14(18)16-15(13)22-16)21-17(20)12(9-19)10-5-3-2-4-6-10/h2-6,11-16,19H,7-9H2,1H3
SMILESCN1C2C[C@@H](OC(=O)C(CO)c3ccccc3)CC1[C@@H]1O[C@H]21

Synonyms

  • Hyoscine
  • Devil's Breath
  • (−)-scopolamine
Pharmacodynamics & Biochemistry

Scopolamine (hyoscine) is a naturally occurring tropane alkaloid, the (–)-isomer, that acts as a competitive antagonist at muscarinic acetylcholine receptors (an antimuscarinic/anticholinergic). Unlike its quaternary derivative butylscopolamine, it is a tertiary amine that readily crosses the blood–brain barrier, so it has marked central as well as peripheral effects. It is a high-affinity, non-selective antagonist across all five muscarinic subtypes (M1–M5), with sub-nanomolar to low-nanomolar affinity (human pKi ≈8.7–9.4). Blocking central muscarinic transmission underlies its anti-motion-sickness, antiemetic, amnestic and, at higher doses, deliriant effects, while peripheral blockade produces the classic anticholinergic signs: dry mouth, dilated pupils, fast heartbeat, reduced secretions and urinary retention. At toxic doses it produces a full central anticholinergic syndrome, confusion, agitation, hallucinations and delirium with amnesia, which is the basis of its reputation as a deliriant and of its criminal use ('Devil's Breath') to incapacitate victims and render them suggestible and amnesic.

Biological targets

  • M1
  • M2
  • M3
  • M4
  • M5

Binding & functional measurements

TargetMeasurementSpecies
M3 receptorpKi 9.4Human
M4 receptorpKi 9.3Human
M1 receptorpKi 9Human
M2 receptorpKi 8.7Human
M5 receptorpKi 8.7Human
Pharmacokinetics
BioavailabilityOral ~20–40% (low, extensive first-pass), transdermal delivery is used to give steady plasma levels
TmaxTransdermal effect builds over several hours, parenteral effect within ~30 min
Half-life≈5 h
VdNot reported
Protein bindingNot reported
MetabolismHepatic (CYP3A4)
ExcretionRenal (largely as metabolites)
Toxicology & Safety
Harm-reduction note: Toxicity and risk depend on dose, route, purity, combinations, setting, and individual health factors. Missing harms should never be interpreted as evidence of safety.

Not reported

Scopolamine is safe and effective at the low doses used for motion sickness and nausea, but it has a narrow margin and is dangerous in overdose. Anticholinergic toxicity produces the classic picture: 'blind as a bat, dry as a bone, red as a beet, hot as a hare, mad as a hatter': dilated pupils and blurred vision, dry flushed skin, fever, and an agitated delirium with hallucinations and amnesia that can progress to seizures, arrhythmia and coma. The elderly are especially susceptible. It is not a euphoriant: its deliriant, amnesic and incapacitating effects are the basis of its criminal use as 'Devil's Breath' (burundanga). Toxicity is additive with other anticholinergic drugs, of which many antihistamines, tricyclics and antipsychotics are examples.[6][7]

Legal Status
Legal note: Legal status can change over time and may vary by country, region, formulation, analogue status, prescription context, and enforcement practice. Always confirm with current official sources before relying on this section.
Interactions & Contraindications

Drug interactions

Anticholinergic drugs Additive anticholinergic toxicity with antihistamines, tricyclics, antipsychotics and other antimuscarinics: dry mouth, retention, hyperthermia and delirium.[6]
Alcohol, Opioids, Benzodiazepines Additive sedation with CNS depressants.[7]
CYP3A4 inhibitors (ritonavir, azole antifungals, macrolides, grapefruit), CYP3A4 inducers (rifampicin, carbamazepine) Strong CYP3A4 inhibitors or inducers can raise or lower scopolamine levels.[6][7]

Contraindications

Closed-angle glaucoma closed-angle (narrow-angle) glaucoma.[6]
Pre-existing bladder or urinary-tract disease, or drug-induced cystitis urinary retention or bladder-outlet obstruction (e.g. prostatic enlargement).[6]
Paralytic ileus or gastrointestinal obstruction gastrointestinal obstruction, paralytic ileus or severe ulcerative colitis.[7]
Myasthenia gravis[6]
Cardiovascular disease, hypertension or arrhythmia tachyarrhythmia, with caution in the elderly (delirium, falls).[6]
Known hypersensitivity to the drug hypersensitivity to scopolamine or other belladonna (tropane) alkaloids.[7]
Usage & Context
  • A widely used antimuscarinic medicine: transdermal patches for motion sickness and postoperative nausea, injectable hyoscine to reduce secretions (anaesthetic premedication, palliative 'death rattle') and for antiemesis, and ophthalmic use as a mydriatic/cycloplegic.
  • Also historically and criminally significant: as a deliriant it has been used (as 'Devil's Breath' / burundanga) to incapacitate victims for robbery or assault, exploiting the amnesia and suggestibility it produces. Recreational use is uncommon and generally dysphoric.
Sources & Evidence

Further Information