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scopolamine

Natural alkaloid, muscarinic antagonist · Anticholinergic

Natural alkaloid, muscarinic antagonistAnticholinergicATC A04AD01
CDSCO approvedATC A04AD01
EXCRETION
—
not curated
INTERACTIONS
5 major
SEVERE in our sources
PREGNANCY
—
not curated
Top interactionssee all 5 →
  • DextropropoxypheneSevereDatabaseDDInter
  • Potassium ChlorideSevereDatabaseDDInter
  • Potassium CitrateSevereDatabaseDDInter
  • TopiramateSevereDatabaseDDInter

Mechanism

Similar to atropine but with prominent central effects at low therapeutic doses due to greater permeation across the blood-brain barrier. Blocks neural pathways from the vestibular apparatus in the inner ear to the emetic center in the brainstem for motion sickness.

Indications

Motion sicknessAdjunct to anesthetic agents (formerly)Preanesthetic medication (formerly)Prevention and treatment of motion sicknessPostoperative nausea and vomiting (some activity)cycloplegiamydriasisiritisuveitisnystagmusSignificant upper airway secretions (during ventilator withdrawal)Death rattle (to reduce secretions)

Dosing

Adult
Transdermal patch: 1.5 mg every 3 days. Also injectable (hydrobromide).

Side effects

Common
DrowsinessAmnesiaFatigueDreamless sleepReduction in REM sleepXerostomia (transdermal patch)Blurred vision (transdermal patch)MydriasisCycloplegiaEuphoriaDry mouthVisual disturbancesConstipation
Serious
  • Excitement
  • Restlessness
  • Hallucinations
  • Delirium (in presence of severe pain, or toxic doses)
  • Psychotic episodes (rare but severe, with transdermal patch)
  • Symptoms following abrupt withdrawal after prolonged use
  • Cardiovascular actions

Drug interactions

Dextropropoxyphene
Severe
Database

Clinical effect not specified

Source: DDInter

Potassium Chloride
Severe
Database

.

Source: DDInter

Potassium Citrate
Severe
Database

Clinical effect not specified

Source: DDInter

Topiramate
Severe
Database

.

Source: DDInter

Zonisamide
Severe
Database

Clinical effect not specified

Source: DDInter

7 additional low-confidence interactions hidden — those rows lack a documented mechanism or management plan in our sources.

Related guidelines

Stroke and TIA — secondary prevention
AHA · Neurology · 2021
Tobacco-related cancer prevention
ICMR · Oncology · 2021
Cardiovascular disease prevention
ESC · Cardiology · 2021
Primary prevention of cardiovascular disease
AHA · Cardiology · 2019
Infective endocarditis prevention
ADA_DENTAL · Dentistry · 2015

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Sources: Goodman & Gilman 14e, Harrison 22e·Verified: 2026-05-10 · House clinical team