Papaverine is a vasodilator that relaxes smooth muscles in your blood vessels to help them dilate (widen). This lowers blood pressure and allows blood to flow more easily through your veins and arteries.

Papaverine is used to treat many conditions that cause spasm of smooth muscle. This includes chest pain, circulation problems, heart attack, or disorders of the stomach or gallbladder.

Papaverine is not for use in treating erectile dysfunction (impotence) and should not be injected into the penis. This practice has resulted in painful or prolonged erection that may require surgery to correct.

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

You should not receive papaverine if you have a serious heart condition such as "AV block."

In an emergency situation it may not be possible to tell your caregivers about your health conditions. Make sure any doctor caring for you afterward knows you have received this medicine.

Papaverine is injected into a muscle, or into a vein through an IV. A healthcare provider will give you this injection.

When injected into a vein, papaverine must be given slowly (over 1 or 2 minutes) to prevent vein irritation or other side effects.

You should not receive papaverine if you are allergic to it, or if you have:

• a serious heart condition such as "AV block."

If possible before you receive papaverine, tell your doctor if you have:

• heart disease;

• high blood pressure;

• glaucoma; or

• liver disease.

It is not known whether papaverine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.

It is not known whether papaverine passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

In an emergency situation it may not be possible to tell your caregivers if you are pregnant or breast feeding. Make sure any doctor caring for your pregnancy or your baby knows you have received this medicine.

Because you will receive papaverine in a clinical setting, you are not likely to miss a dose.

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

Overdose symptoms may include weakness, drowsiness, dizziness, vomiting, double vision, sweating, warmth or redness, fast heartbeats, and uncontrolled eye movement.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

papaverine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Drinking alcohol can increase certain side effects of papaverine.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Papaverine may cause serious side effects. Call your doctor at once if you have:

• upper stomach pain, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

• skin rash, bruising, severe tingling, numbness, pain, muscle weakness;

• severe headache, blurred vision, fast heart rate, pounding in your neck or ears, anxiety, shortness of breath;

• extreme drowsiness;

• vision changes; or

• pain, swelling, or redness where the medicine was injected.

Common side effects of papaverine may include:

• nausea, upset stomach, loss of appetite, constipation, diarrhea;

• general ill feeling;

• headache, drowsiness, dizziness or spinning sensation;

• flushing (warmth, redness, or tingly feeling);

• skin rash, increased sweating; or

• tiredness, lack of energy.

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.

Taking this medicine with other drugs that make you sleepy can worsen this effect. Ask your doctor before taking papaverine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Other drugs may interact with papaverine, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain tests to monitor your liver function.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.