COMMON BRAND NAME(S): Anaspaz, Cystospaz, Donnamar, Levsin



Description: Hyoscyamine blocks the action of acetylcholine at parasympathetic sites in smooth muscle, secretory glands and the CNS. It increases cardiac output, dries secretions and antagonises histamine and serotonin.
Onset: 2-3 min.
Duration: 4-6 hr.
Absorption: Well absorbed.
Distribution: Protein-binding: 50%.
Metabolism: Hepatic.
Excretion: Via urine; 3-5 hr (elimination half-life).

Hyoscyamine is used to treat a variety of problems such as:

  • stomach /intestinal cramps
  • irritable bowel syndrome
  • bladder and bowel control problems
  • cramping pain caused by kidney stones and gallstones
  • Parkinson’s disease
  • side effects of certain medications (drugs used to treat myasthenia gravis) and insecticides


This medication belongs to a class of drugs known as anticholinergics/antispasmodics. It works by decreasing acid production in the stomach, slowing down the natural movements of the gut, relaxing muscles in many organs (e.g., stomach, intestines, bladder, kidney, gallbladder), and lessens the amount of certain body fluids (e.g., saliva, sweat).


How to use hyoscyamine

Take this medication by mouth as prescribed, usually 30-60 minutes before meals, or as directed by your doctor.


Dosage is based on your medical condition and response to therapy. Do not increase your dose or take it more often than prescribed without consulting your doctor. Adults and children 12 years and older should not take more than 1.5 milligrams in 24 hours. Children aged 2 to 12 years should not take more than 0.75 milligrams in 24 hours. Ask your doctor or pharmacist for more information.


Antacids lower the absorption of hyoscyamine. If you use antacids, take them after meals and take hyoscyamine before meals; or take antacids at least 1 hour after taking hyoscyamine.


Drink plenty of fluids while taking this medication unless your doctor directs you otherwise.


Inform your doctor if your condition persists or worsens.

Notify your doctor or pharmacist promptly if any of these effects persist or worsen:


  • Dizziness
  • Drowsiness
  • blurred vision
  • dry mouth
  • vision problems
  • headache
  • trouble sleeping
  • constipation
  • flushing
  • dry skin
  • decreased sweating



To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute.


Tell your doctor immediately if any of these unlikely but serious side effects occur:


  • mental/mood changes (e.g., confusion, unusual excitement)
  • fast/irregular heartbeat
  • difficulty urinating
  • decreased sexual ability
  • loss of coordination
  • slurred speech
  • vomiting



Get medical help right away if you have any very serious side effects, including: eye pain/swelling/redness, vision changes (such as seeing rainbows around lights at night).


A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include:


  • rash
  • itching/swelling (especially of the face/tongue/throat)
  • severe dizziness
  • trouble breathing



This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

If overdose is suspected, contact a poison control center or emergency room immediately. Symptoms of overdose may include hot/dry skin, fever, unusual excitement, fast/irregular heartbeat, seizures.



Do not share this medication with others.


Management of digestive disorders may include lifestyle changes such as stress reduction programs, exercise, stopping smoking, and dietary changes to increase the effectiveness of this medicine. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.


Missed Dose

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.



Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.


Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.




There are no brands containing this molecule.

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