Hyoscyamine is used in the treatment of pain relief.

Hyoscyamine belongs to a class of drugs called anti-muscarinics. It blocks the action of a chemical called acetylcholine that controls muscle contractions and secretion of body fluids such as mucus, stomach/intestinal acid, and thus causes decrease in the movement of gut, relaxes muscles and controls secretions along the digestive tract..

Nervousness, Confusion, Constipation, Dilation of the pupil of the eye, Dizziness, Drowsiness, Dryness in mouth, Difficulty in swallowing, Difficulty in urination, Accomodation disorder, Eye muscle paralysis, Fever, Heartburn, Increased intraocular pressure, Insomnia (difficulty in sleeping), Skin redness, Tachycardia, Vomiting, Weakness, Raised itchy skin rash, Allergic reaction

• Do consult your doctor before taking hyoscyamine, if you have any of the following medical conditions: nerve disorders, overactive thyroid (hyperthyroidism), heart problems (coronary heart disease, congestive heart failure, irregular heartbeats), high blood pressure, increased pressure inside the eye (glaucoma), kidney disease, hiatal hernia (a condition related to the stomach and the food pipe that causes acid reflux and heart burn problems) and myasthenia gravis (a disease characterized by very weak and unusually tired muscles).
• Hyoscyamine may cause drowsiness, dizziness, blurred vision, or lightheadedness. Do not drive or operate machinery until you feel fine.
• Do not drink alcohol or use medicines that may cause drowsiness (eg, sleeping pills, muscle relaxants) while you are using hyoscyamine as it may have an additive effect. 
• Take precautions to not become overheated or dehydrated in hot weather as this may lead to heatstroke.
• Drink plenty of fluids and maintain good oral hygiene to relieve dry mouth.
• Take appropriate care while going in sunlight as hyoscyamine may make your eyes more sensitive to sunlight.
• Always take hyoscyamine 1 hour before or 2 hours after taking any antacids.
• If you are having surgery, including dental surgery, tell your doctor or dentist that you take hyoscyamine.
• Tell your doctor if you are or planning to become pregnant or are breastfeeding.

Ques. Q. Is Hyoscyamine over the counter?
No. Hyoscyamine is not an over the counter (OTC) drug. It can be obtained only on producing a valid prescription

Ques. Q. Is Hyoscyamine a controlled substance?
No. Hyoscyamine is not a controlled substance

Ques. Q. Is Hyoscyamine addictive?
It has no potential for addiction or abuse

Ques. Q. Is Hyoscyamine a steroid/ narcotic/ sulfa drug?
No. It does not have a chemical structure or effects similar to steroids or sulfa drugs

Ques. Q. Does Hyoscyamine contain sulfa?
It does not induce sleep and is not a narcotic drug

Ques. Q. Is Hyoscyamine a muscle relaxer?
Hyoscyamine blocks the action of a chemical called acetylcholine, and relaxes muscles of stomach and intestine and provides relief from abdominal cramps

Ques. Q. Is Hyoscyamine a pain killer?
Hyoscyamine is not a pain killer

Ques. Q. Does Hyoscyamine help with pain?
However, by reducing muscle contractions it provides relief from pain due to cramps

Ques. Q. Can I take hyoscyamine with Benadryl/ Xanax/ Prevacid/ Omeprazole/ ibuprofen/ Tylenol/ Aleve?
Hyoscyamine has no known harmful interaction with active ingredients in Benadryl, Xanax (alprazolam), Prevacid (lansoprazole), omeprazole, ibuprofen, Tylenol (acetaminophen) or Aleve (naproxen). Please inform your doctor about all medication you are currently taking to avoid any harmful drug interaction

Ques. Q. Can I take Imodium/ Bentyl/ Percocet with Hyoscyamine?
Concomitant use of Hyoscyamine with Imodium (loperamide), Bentyl (dicyclomine) and Percocet (acetaminophen + oxycodone) can cause harmful drug interactions and should be avoided. Please inform your doctor about all medication you are currently taking to avoid any harmful drug interaction

Ques. Q. Does Hyoscyamine cause or stop diarrhea?
Treatment with Hyoscyamine may be helpful in controlling diarrhea associated with bowel spams; however, it can aggravate constipation. Contact your doctor immediately if you experience diarrhea as a side effect of Hyoscyamine treatment

Ques. Q. Does Hyoscyamine make you high/gain weight?
No. Hyoscyamine does not produce a psychological feeling of extreme happiness or colloquially known as 'feeling high'. Weight gain is not among the known side effects of Hyoscyamine

Ques. Q. Does Hyoscyamine help with gas/ nausea?
Hyoscyamine may provide relief from gas or nausea if they are symptoms of intestinal bowel syndrome or other gastrointestinal problems for which Hyoscyamine is given as a treatment. Nausea is also a common side effect of Hyoscyamine treatment

Ques. Q. Does Hyoscyamine cause constipation?
Constipation is a common side effect of Hyoscyamine treatment.