• If you are allergic to anything, including medicines, dyes, additives, or foods.

• If you have a slow or abnormal heart beat, heart block, heart failure, or any problem with the heart's electrical system, including long Q-T syndrome. Droperidol can slow down the heart's electrical impulses and make these problems worse. Your doctor may check your heart's electrical system by getting an electrocardiogram (ECG) before you get this drug.

• If you have low potassium or low magnesium, or if you are taking medicines such as diuretics ("water pills") that may cause this problem. Droperidol can slow down the heart's electrical impulses and these problems may make it more dangerous.

• If you take tranquilizers (sedatives) such as diazepam (Valium) or drink a lot of alcohol. This may increase the chance of the heart rhythm problems.

• If you have liver or kidney disease. Droperidol can pose a higher risk of side effects if these are present.

• If you have taken chemotherapy drugs that can damage the heart, such as daunorubicin, doxorubicin, epirubicin, or idarubicin. These medicines may worsen the effects on the heart.

• If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy.

• If you are breast-feeding. This drug may pass into breast milk and affect the baby.

• About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Medicines that make you urinate more (diuretics or "water pills") may worsen electrical problems with the heart by lowering your potassium and magnesium levels.

Epinephrine may lower the blood pressure (rather than raise it) if it is given with droperidol. The doctor can substitute another drug if epinephrine's effects are needed.

Droperidol may make you drowsy. This can add to the effects of other medicines or substances that make you sleepy or less alert, such as:

• antihistamines
• tranquilizers (sedatives)
• sleeping pills
• muscle relaxers
• barbiturates
• anti-seizure medicines
• opioid pain medicines
• anesthetics
• antidepressants such as amitriptyline, desipramine, doxepin, imipramine, nortriptyline
• anti-psychotic drugs
• certain anti-nausea medicines
• alcohol

Check with your doctor, nurse, or pharmacist about whether any of the medicines, vitamins, herbs, and supplements you are taking can cause problems with this medicine.

This drug may cause a quick drop in blood pressure when you go from lying down to sitting up, or from sitting to standing up (postural hypotension). This may cause you to feel dizzy or faint if you sit up or stand up too quickly, which can cause falls or injuries. Changing position slowly can reduce the risk of these problems. Let your doctor know if this happens to you.

Drink plenty of liquids. This medicine can cause low blood pressure and other effects that can be more dangerous if you are dehydrated.

Droperidol can cause unplanned movements called extrapyramidal effects. These include restlessness, tremors, sticking out the tongue, and involuntary muscle contractions. Let your doctor or nurse know right away if this happens. These side effects can usually be stopped by taking other medicines such as diphenhydramine (Benadryl), although in some cases, it may be necessary to stop droperidol altogether.

In rare cases, droperidol can cause changes in the heart's rhythm, some of which can be dangerous. Get emergency help if you have irregular heart beat, blue nail beds or skin, trouble breathing, or seizure.

This drug can cause a rare problem called neuroleptic malignant syndrome, with symptoms like fever, tight muscles, tremors, sweating, constipation, and confusion. This syndrome can become life-threatening if not treated right away. If you have symptoms like these, call your doctor without delay.

• feeling very calm (sedated)*
• sleepiness*
• low blood pressure* which can make you feel dizzy or faint*

• decreased breathing rate
• increased heart rate
• restlessness and anxiety

• cough
• chills
• facial sweating
• shivering
• neck spasms (cramps) and tightness in the throat, trouble swallowing
• changes in electrical impulses in the heart*
• low blood pressure*
• high body temperature*
• slow or fast heart rate*
• allergic reaction
• unplanned or involuntary movements (extrapyramidal symptoms)*

*See "Precautions" section for more detailed information.