Phenohytro is made up of belladonna alkaloids (atropine, hyoscyamine, scopolamine) and phenobarbital.

Phenohytro is a combination medicine used to treat irritable bowel syndrome and ulcers in the intestine.

Phenohytro may also be used for purposes not listed in this medication guide.

Phenohytro may be habit-forming. Misuse can cause addiction, overdose, or death.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Phenohytro contains phenobarbital, a barbiturate that may be habit-forming. Misuse can cause addiction, overdose, or death. Keep the medication in a place where others cannot get to it. Selling or giving away this medicine is against the law.

Swallow the extended-release tablet whole and do not crush, chew, or break it.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Call your doctor if your symptoms do not improve, or if they get worse.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using Phenohytro.

Store at room temperature away from moisture, heat, and light. Keep track of your medicine. You should be aware if anyone is using it improperly or without a prescription.

Do not stop using this medicine suddenly after long-term use, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using this medicine.

You should not use this medicine if you are allergic to atropine, hyoscyamine, phenobarbital, or scopolamine. You also should not use this medicine if you have:

• a bladder obstruction, enlarged prostate, or other urination problems;

• a stomach or bowel obstruction (including paralytic ileus);

• chronic constipation or lack of bowel function (especially in older adults and those who are ill or debilitated);

• severe ulcerative colitis or toxic megacolon;

• glaucoma;

• reflux disease with a hiatal hernia;

• active bleeding with fast heartbeats, low blood pressure, shortness of breath, and cold hands or feet;

• porphyria (a genetic enzyme disorder that causes symptoms affecting the skin or nervous system);

• an allergy to primidone; or

• a muscle disorder called myasthenia gravis.

Tell your doctor if you have ever had:

• ulcerative colitis or a stomach ulcer;

• a colostomy or ileostomy;

• a nerve-muscle disorder;

• heart problems, high blood pressure;

• gallbladder disease;

• alcoholism or drug addiction;

• breathing problems;

• a thyroid disorder; or

• liver or kidney disease.

Phenohytro may harm an unborn baby, but the benefit of treating your condition with this medicine may outweigh any risk. Tell your doctor if you are pregnant or if you become pregnant.

This medicine can make birth control pills less effective. Ask your doctor about using a non-hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk. This medicine can slow breast milk production.

Do not give this medication to a child without the advice of a doctor.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include headache, dizziness, nausea, vomiting, dry mouth, blurred vision, hot or dry skin, trouble swallowing, and feeling excited or agitated.

Phenohytro may cause drowsiness or blurred vision and may impair your reactions. Avoid driving or hazardous activity until you know how this medicine will affect you.

Drinking alcohol with this medicine can increase certain side effects.

Avoid becoming overheated or dehydrated during exercise and in hot weather. This medicine can decrease sweating and you may be more prone to heat stroke.

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

This medicine may cause serious side effects. Stop using this medicine and call your doctor at once if you have:

• fast or pounding heartbeats;

• blurred vision, tunnel vision, eye pain, or seeing halos around lights;

• diarrhea (especially if you have a colostomy or ileostomy);

• decreased sweating and hot or dry skin;

• painful or difficult urination;

• loss of coordination, slurred speech, fainting;

• confusion, agitation, depression, suicidal thoughts;

• fever, sore throat; or

• pale skin, easy bruising, unusual tiredness, cold hands and feet;

Side effects such as drowsiness, agitation, nervousness, and excitement may be likely to occur in older adults.

Common side effects of Phenohytro may include:

• constipation;

• decreased sweating or urination;

• dizziness, drowsiness, weakness;

• blurred vision;

• feeling nervous or excited;

• dry mouth, nose, or throat;

• dry skin; or

• nausea, vomiting, bloating.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Using this medicine with other drugs that slow your breathing can cause dangerous side effects. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

If you take an antacid, take it at least 3 hours before or 3 hours after you take Phenohytro.

When you start or stop taking Phenohytro, your doctor may need to adjust the doses of any other medicines you take on a regular basis. Tell your doctor about all your other medicines, especially:

• potassium supplements;

• primidone;

• St. John's wort;

• antibiotic or antifungal medicine;

• heart or blood pressure medication;

• antiviral medicine to treat hepatitis or HIV/AIDS; or

• a blood thinner (such as warfarin, Coumadin, Jantoven).

This list is not complete. Other drugs may affect Phenohytro, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.