Hyoscyamine Sulfate

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Jan 13, 2023

Warnings

Hyoscyamine Risks, Warnings, and Complications

Hyoscyamine can cause or worsen health problems in some people. Talk to your doctor or pharmacist about other treatment options if you are at increased risk of complications from hyoscyamine use.

REDUCED MENTAL ALERTNESS AND MOOD CHANGES: Levsin SL (hyoscyamine) can reduce your ability to focus, think, and react. Avoid activities that require mental alertness, such as driving a car or operating heavy machinery, until you know how this medication affects you. Tell your healthcare provider if you notice any disorientation, confusion, hallucinations, inappropriate affect, or unusual excitement while on hyoscyamine. Your doctor may tell you to stop taking hyoscyamine. These symptoms usually go away in a day or two.
INTESTINAL BLOCKAGE: Diarrhea can be an early symptom of intestinal blockage. Taking hyoscyamine in this case can make the condition worse. Your healthcare provider will make sure you do not have a blockage in your intestines before starting you on hyoscyamine. Contact your doctor without delay if you experience diarrhea during hyoscyamine treatment.
HEAT STROKE: Hyoscyamine has a drying effect and makes you sweat less. This can put you at risk of heat stroke, especially if you do strenuous exercise in hot weather and become dehydrated. Avoid extreme heat and be careful while doing anything that can make you overheated, such as strenuous exercise in the sun or use of a sauna. Stay well hydrated and remain in shady areas when outdoors. Seek immediate medical help if you develop signs of heat stroke such as confusion, headache, dizziness, excessive sweating, fast breathing, fast heartbeat, fever, pain, extreme thirst, or stomach cramps.
FAST HEART RATE: Hyoscyamine sulfate medicine affects your heart rate. Fast heart rate on hyoscyamine is more likely to occur in people who have a history of irregular heart rhythm, high blood pressure, heart disease, thyroid disease, nerve problems, or kidney disease. Tell your healthcare provider about any pre-existing medical condition before starting hyoscyamine, so that they can make sure it is safe for you to take this medicine.
ADDITIVE ANTICHOLINERGIC EFFECTS: Hyoscyamine and other anticholinergic agents administered concomitantly can lead to additive anticholinergic effects. Medications that can have systemic anticholinergic effects like hyoscyamine include certain Parkinson’s medications, psychiatric drugs, antidepressants, and antihistamines. Give your doctor and pharmacist a complete list of all the medicines you take to avoid drug interactions and additive anticholinergic effects. If any unusual side effects occur after starting the medicine, contact your doctor without delay.

Precautions Before Starting Hyoscyamine

Tell your healthcare provider if you have ever had an allergic reaction to hyoscyamine, other allergy medicines, or any other drugs. Your pharmacy can give you a full list of active and inactive ingredients in hyoscyamine tablets and liquid formulations.

Give your doctor and pharmacist a complete list of your medications, including prescription drugs, non-prescription drugs, vitamins, and herbal supplements. This can help avoid dangerous interactions between your medications.

Give your doctor a complete medical history. Hyoscyamine may not be right for people with certain medical conditions, such as heart, lung, kidney, or liver disease, glaucoma, intestinal obstruction, ulcerative colitis, urinary tract obstruction, enlarged prostate, or myasthenia gravis.

Tell your doctor if you are pregnant or breast feeding. It is unclear if this drug passes into breast milk. However, anticholinergic agents like hyoscyamine can decrease milk production in nursing mothers.

If you are an older adult (age 65 years and older), talk to your doctor about the benefits versus risks of taking hyoscyamine. There may be other safer medications to treat your condition.

Precautions During Use of Hyoscyamine

Keep all your doctors’ and laboratory appointments during your treatment with hyoscyamine. This medication will ease your symptoms but it will not treat your condition. Continue taking hyoscyamine even if you feel well. Do not stop taking hyoscyamine without your doctor’s approval.

Take antacids 1-2 hours away from hyoscyamine as they can interfere with hyoscyamine absorption.

Tell your doctor if you become pregnant while taking hyoscyamine.

Tell all your healthcare providers you are on hyoscyamine, especially before any surgery, including dental procedures.

Hyoscyamine can cause drowsiness, dizziness, and reduced mental alertness. Be careful while driving, operating heavy machinery, or doing anything that requires full concentration until you know how this medicine affects you.

Avoid alcoholic drinks while on hyoscyamine. Drinking alcohol can worsen side effects like nervousness, confusion, dizziness, and drowsiness, putting you at risk of accidents and injuries.

Hyoscyamine Drug Interactions

Certain other drugs can affect how hyoscyamine works. Possible interactions between hyoscyamine and other medicines can increase the risk of severe adverse effects.

Some medicines that may interact with hyoscyamine include:

Parkinson’s medications like amantadine (Symmetrel, Symadine).
Mental depression medicines like amitriptyline (Elavil), nortriptyline (Pamelor), doxepin (Sinequan), desipramine (Norpramin), imipramine (Tofranil), clomipramine (Anafranil), protriptyline (Vivactil), and trimipramine (Surmontil).
Antidepressants called monoamine oxidase (MAO) inhibitors, such as phenelzine (Nardil) and tranylcypromine (Parnate).
Psychiatric medications like chlorpromazine (Thorazine), haloperidol (Haldol), fluphenazine (Prolixin), mesoridazine (Serentil), perphenazine (Trilafon), promazine (Sparine), prochlorperazine (Compazine), thioridazine (Mellaril), trimeprazine (Temaril), triflupromazine (Vesprin), and trifluoperazine (Stelazine).
Belladonna containing medications (Donnatal).
Antihistamines like promethazine (Phenergan).

This is not a complete list of hyoscyamine drug interactions. Give your doctor and pharmacist a list of all the medicines you take, including prescription drugs, OTC (non-prescription) drugs, dietary supplements, and herbal products. Also, tell your healthcare professionals if you smoke, drink alcohol, or use illegal drugs because some of these substances can cause serious health complications when used with prescription medications.

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