Hyoscyamine

Mechanism-of-action classes: Cholinergic Muscarinic Antagonists; Histamine Receptor Antagonists; Serotonin Antagonists.

• Hyoscyamine sulfate extended-release tablets are effective as adjunctive therapy in the treatment of peptic ulcer. They can also be used to control gastric secretion, visceral spasm and hypermotility in spastic colitis, spastic bladder, cystitis, pylorospasm, and associated abdominal cramps.

• Glaucoma; obstructive uropathy (for example, bladder neck obstruction due to prostatic hypertrophy); obstructive disease of the gastrointestinal tract (as in achalasia, pyloroduodenal stenosis); paralytic ileus, intestinal atony of elderly or debilitated patients; unstable cardiovascular status in acute hemorrhage; severe ulcerative colitis; toxic megacolon complicating ulcerative colitis; myasthenia gravis.contraindicated

Dosage may be adjusted according to the conditions and severity of symptoms. Adults And Pediatric Patients 12 Years Of Age And Older 1 to 2 tablets every 12 hours. Do not crush or chew tablets. Do not exceed 4 tablets in 24 hours.

In the presence of high environmental temperature, heat prostration can occur with drug use (fever and heat stroke due to decreased sweating). Diarrhea may be an early symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy. In this instance, treatment with this drug would be inappropriate and possibly harmful. Like other anticholinergic agents, hyoscyamine sulfate may produce drowsiness, dizziness, or blurred vision. In this event, the patient should be warned not to engage in activities requiring mental alertness such as operating a motor vehicle or other machinery or to perform hazardous work while taking this drug. Psychosis has been reported in sensitive individuals given anticholinergic drugs including hyoscyamine sulfate. CNS signs and symptoms include confusion, disorientation, short-term memory loss, hallucinations, dysarthria, ataxia, euphoria, anxiety, fatigue, insomnia, agitation and mannerisms, and inappropriate affect. These CNS signs and symptoms usually resolve within 12 to 48 hours after discontinuation of the drug.

All of the following adverse reactions have been reported with hyoscyamine sulfate. Adverse reactions may include dryness of the mouth; urinary hesitancy and retention; blurred vision; tachycardia; palpitations; mydriasis; increased ocular tension; loss of taste; headache; nervousness; drowsiness; weakness; fatigue; dizziness; insomnia; nausea; vomiting; impotence; constipation; bloated feeling; abdominal pain; diarrhea; allergic reactions or drug idiosyncrasies; urticaria and other dermal manifestations; ataxia; speech disturbance; some degree of mental confusion and/or excitement (especially in elderly persons); short-term memory loss; hallucinations; and decreased sweating.

Pregnancy – Pregnancy Category C Animal reproduction studies have not been conducted with hyoscyamine sulfate. It is also not known whether hyoscyamine sulfate can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Hyoscyamine sulfate should be given to a pregnant woman only if clearly needed.

The signs and symptoms of overdose are headache, nausea, vomiting, blurred vision, dilated pupils, hot dry skin, dizziness, dryness of the mouth, difficulty in swallowing, and CNS stimulation. Measures to be taken are immediate lavage of the stomach and injection of physostigmine 0.5 to 2 mg intravenously and repeated as necessary up to a total of 5 mg. Fever may be treated symptomatically (tepid water sponge baths, hypothermic blanket). Excitement to a degree which demands attention may be managed with sodium thiopental 2% solution given slowly intravenously or chloral hydrate (100-200 mL of a 2% solution) by rectal infusion. In the event of progression of the curare-like effect to paralysis of the respiratory muscles, artificial respiration should be instituted and maintained until effective respiratory action returns. In rats, the LD 50 for hyoscyamine is 375 mg/kg. Hyoscyamine sulfate is dialyzable.

1. 1Nausea8968.9%
2. 2Diarrhoea7757.7%
3. 3Pain7417.4%
4. 4Fatigue6946.9%
5. 5Drug Ineffective6056.0%
6. 6Headache5795.8%
7. 7Dizziness5785.8%
8. 8Vomiting5275.2%
9. 9Abdominal Pain5265.2%
10. 10Dyspnoea4864.8%
11. 11Anxiety4524.5%
12. 12Off Label Use4354.3%
13. 13Fall4294.3%
14. 14Asthenia3833.8%
15. 15Weight Decreased3823.8%

Recent PubMed references pinned to Hyoscyamine as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• A Pull-Block Metabolic Engineering Strategy for High-Yield and High-Purity Hyoscyamine Production in Atropa belladonna.
  Biotechnology journal · 2026 · Zeng L, Chen H, Wen M, et al.
  PMID 41645580DOI 10.1002/biot.70187
• Refining the Substrate-Cofactor Disposition Model of Hyoscyamine 6β-Hydroxylase Catalysis Using Hyoscyamine Analogs.
  Journal of the American Chemical Society · 2025 · Ushimaru R, Chen R, Fan PH, et al.
  PMID 41329847DOI 10.1021/jacs.5c17484
• Multiple independent losses of the biosynthetic pathway for two tropane alkaloids in the Solanaceae family.
  Nature communications · 2023 · Yang J, Wu Y, Zhang P, et al.
  PMID 38114555DOI 10.1038/s41467-023-44246-3
• Assessment of tropane alkaloid levels in Brazilian buckwheat flour products: A novel LC-UHPLC-MS/MS approach using solid-liquid extraction at low temperature.
  Food chemistry · 2024 · Caminhas LD, Freitas Pereira de Souza G, Rath S, et al.
  PMID 37983999DOI 10.1016/j.foodchem.2023.138010
• Tropinone reductase: A comprehensive review on its role as the key enzyme in tropane alkaloids biosynthesis.
  International journal of biological macromolecules · 2023 · Hu X, Liu W, Yan Y, et al.
  PMID 37839598DOI 10.1016/j.ijbiomac.2023.127377
• Simultaneous quantification of hyoscyamine and scopolamine using HPLC-DAD in four Solanaceae: Hyoscyamus niger, Datura stramonium, Atropa belladonna and Mandragora officinarum.
  Natural product research · 2025 · Piatti D, Marconi R, Angeloni S, et al.
  PMID 37830795DOI 10.1080/14786419.2023.2269595
• Viral inhibitory potential of hyoscyamine in Japanese encephalitis virus-infected embryonated chicken eggs involving multiple signaling pathways.
  Archives of virology · 2023 · Bhattacharjee A, Naga R, Saha M, et al.
  PMID 37787913DOI 10.1007/s00705-023-05883-7
• Hyoscyamine induces developmental toxicity by disrupting metabolism in zebrafish embryo (Danio rerio).
  Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association · 2023 · Lv Y, Lin Z, Chen J, et al.
  PMID 37263572DOI 10.1016/j.fct.2023.113860

The 10 most recently updated of 500 ClinicalTrials.gov registrations naming Hyoscyamine as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Toripalimab Combined With Platinum-based Chemotherapy With or Without H1 Receptor Antagonist in the Perioperative Treatment of Resectable Non-small Cell Lung Cancer
  Not yet recruiting · Phase 2 · Interventional · 120 enrolled · Tianjin Medical University Cancer Institute and Hospital
  NCT07358689updated 2026-06-12
• Efficacy and Safety of 0.01%, 0.03%, and 0.05% Atropine Eye Drops in Reducing Myopia Progression
  Completed · Phase 3 · Interventional · 95 enrolled · Khyber Medical College, Peshawar
  NCT07626892updated 2026-06-10
• Efficacy of Pregabalin for Patients With Irritable Bowel Syndrome
  Recruiting · Interventional · 258 enrolled · Beijing Tiantan Hospital
  NCT07635394updated 2026-06-09
• Respiratory Effect of the LISA Method With Sedation by Propofol Versus Absence of Sedation.
  Completed · Phase 3 · Interventional · 233 enrolled · University Hospital, Grenoble
  NCT04016246updated 2026-06-09
• Comparison of Spinal Anesthesia Adjuvant and Quadratus Lumborum Block on the Opioid Requirement and Perioperative Pain of Laparoscopic Kidney Transplant Donor
  Completed · Interventional · 60 enrolled · Indonesia University
  NCT06764667updated 2026-06-08
• Minimal Flow Anesthesia and Infection Risk
  Completed · Interventional · 140 enrolled · Ankara City Hospital Bilkent
  NCT07092046updated 2026-06-05
• 0.01% and 0.025% Atropine Eye Drops Combined Auricular Acupoint Stimulation on Myopia Control and Corneal Endothelium Change
  Enrolling by invitation · Interventional · 420 enrolled · China Medical University Hospital
  NCT07537166updated 2026-06-04
• A RCT of Spectacles With Aspherical Lenslets or 0.05% Atropine for Myopia Control
  Recruiting · Phase 3 · Interventional · 348 enrolled · Jaeb Center for Health Research
  NCT07095894updated 2026-06-04
• Atropine Alone vs Atropine Plus Bifocal Spectacles for Myopia Control in Children
  Completed · Interventional · 210 enrolled · University of Faisalabad
  NCT07614113updated 2026-05-29
• Safety and Accuracy of Regadenoson-Atropine Stress Echocardiography in CAD
  Terminated · Interventional · 45 enrolled · Henry Ford Health System
  NCT00894179updated 2026-05-22

Frequently asked questions

How does Hyoscyamine work?

Mechanism-of-action classes: Cholinergic Muscarinic Antagonists; Histamine Receptor Antagonists; Serotonin Antagonists.

What is Hyoscyamine used for?

According to FDA labeling, Hyoscyamine carries indications including: Hyoscyamine sulfate extended-release tablets are effective as adjunctive therapy in the treatment of peptic ulcer. They can also be used to control gastric secretion, visceral spasm and hypermotility in spastic colitis, spastic bladder, cystitis, pylorospasm, and associated abdominal cramps.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Hyoscyamine?

Hyoscyamine is classified as Belladonna alkaloids, tertiary amines, Cholinergic Muscarinic Antagonists, Histamine Receptor Antagonists, Serotonin Antagonists, Cardiovascular Activity Alteration, Decreased Respiratory Secretions.

What are the brand names for Hyoscyamine?

Hyoscyamine is marketed under brand names including Anaspaz, Digenyx, Digex, Donnatal, Ed Spaz, Hyophen, Levbid, Levsin.

What are the contraindications for Hyoscyamine?

Hyoscyamine labeling lists contraindications including: Glaucoma; obstructive uropathy (for example, bladder neck obstruction due to prostatic hypertrophy); obstructive disease of the gastrointestinal tract (as in achalasia, pyloroduodenal stenosis); paralytic ileus, intestinal atony of elderly or debilitated patients; unstable cardiovascular status in acute hemorrhage; severe ulcerative colitis; toxic megacolon complicating ulcerative colitis; myasthenia gravis.. Always consult the full prescribing information and a clinician.