Stop using promethazine and call your doctor at once if you have twitching or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs. These could be early signs of dangerous side effects. Promethazine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert. Avoid drinking alcohol, which can increase some of the side effects of promethazine. There are many other medicines that can interact with promethazine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor or other healthcare provider who treats you.

Important safety information:

Promethazine should not be given to a child younger than 2 years old. Promethazine can cause severe breathing problems or death in a child younger than 2. Carefully follow your doctor's instructions when giving this medicine to a child of any age. Do not use this medication if you have severe asthma, emphysema, or other breathing problem, or if you are allergic to promethazine or other phenothiazines such as chlorpromazine (Thorazine), fluphenazine (Permitil), perphenazine (Trilafon), prochlorperazine (Compazine, Compro), thioridazine (Mellaril), or trifluoperazine (Stelazine).

If you have certain conditions, you may need a dose adjustment or special tests to safely use this medication. Before you take promethazine, tell your doctor if you have:

a history of seizures;

heart disease or high blood pressure;

liver or kidney disease;

severe asthma, emphysema, chronic obstructive pulmonary disease (COPD) or other breathing problem;

sleep apnea (breathing stops during sleep);

glaucoma;

a stomach ulcer or digestive obstruction;

bone marrow depression;

adrenal gland tumor (pheochromocytoma);

enlarged prostate or problems with urination;

low levels of calcium in your blood (hypocalcemia); or

if you have ever had a serious side effect while using promethazine or any other phenothiazine.

FDA pregnancy category C. It is not known whether promethazine is harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. It is not known whether promethazine passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby. Older adults may be more likely to have side effects from promethazine.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using promethazine and call your doctor at once if you have any of these serious side effects:

twitching, or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs;

tremor (uncontrolled shaking), drooling, trouble swallowing, problems with balance or walking;

feeling restless, jittery, or agitated;

high fever, stiff muscles, confusion, sweating, fast or uneven heartbeats, rapid breathing;

feeling like you might pass out;

seizure (convulsions);

pale skin, easy bruising or bleeding, fever, sore throat, flu symptoms;

decreased night vision, tunnel vision, watery eyes, increased sensitivity to light;

hallucinations, agitation;

nausea and stomach pain, skin rash, and jaundice (yellowing of the skin or eyes);

urinating less than usual or not at all;

joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color; or

slow heart rate, weak pulse, fainting, slow breathing (breathing may stop).

Less serious promethazine side effects may include:

dizziness, drowsiness, anxiety;

blurred vision, dry mouth, stuffy nose;

ringing in your ears;

weight gain, swelling in your hands or feet;

impotence, trouble having an orgasm; or

constipation.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.