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Systematic (IUPAC) name
(8-methyl-8-azabicyclo[3.2.1]oct-3-yl) 3-hydroxy-2-phenyl-propanoate
CAS number 101-31-5
ATC code A03BA03
PubChem 3661
DrugBank APRD00607
Chemical data
Formula C17H23NO3 
Mol. mass 289.375 g/mol
Pharmacokinetic data
Bioavailability 50% Protein binding
Metabolism Hepatic
Half life 3-5 hrs.
Excretion Urine
Therapeutic considerations
Pregnancy cat.


Legal status

Prescription only (US)

Routes Oral, Injection

Hyoscyamine is a chemical compound, a tropane alkaloid it is the levo-isomer to atropine. It is a secondary metabolite of some plants, particularly henbane (Hyoscamus niger.)

Brand names for hyoscyamine include Symax, Anaspaz, Buwecon, Cystospaz, Levsin, Levbid, Donnamar, NuLev, and Neoquess.



Hyoscyamine is used to provide symptomatic relief to various gastrointestinal disorders including spasms, peptic ulcers, irritable bowel syndrome, pancreatitis, colic and cystitis. It has also been used to relieve some heart problems, control some of the symptoms of Parkinson's disease, as well as for control of respiratory secretions in end of life care.

Side effects

Side effects include dry mouth and throat, eye pain, blurred vision, restlessness, dizziness, arrythmia, flushing, faintness. An overdose will cause headache, nausea, vomiting and CNS symptoms including disorientation, hallucinations, euphoria, inappropriate affect, short-term memory loss and coma.


Hyoscyamine is an antimuscarinic, working by blocking the action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands and the CNS; increases cardiac output, dries secretions, and antagonizes serotonin.


Hyoscyamine can be extracted from plants of the Solanaceae family, notably Datura stramonium. Empirically it is C17H23NO3. Its structural name is α-(hydroxymethyl)-, 8-methyl-8-azabicyclo[3.2.1]oct-3-yl ester, [3(S)-endo]-1αH,5αH-Tropan-3α-ol. Do not crush, chew, or divide the extended-release capsules


Drug Information Handbook 11th Ed. pp. 710-11. Lexi-Comp

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hyoscyamine". A list of authors is available in Wikipedia.
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