Generic Name: promethazine (oral) (pro METH a zeen)
Brand Name: Phenergan
Medically reviewed on October 16, 2017.
What is promethazine?
Promethazine is in a group of drugs called phenothiazines (FEEN-oh-THYE-a-zeens). It works by changing the actions of chemicals in your brain. Promethazine also acts as an antihistamine. It blocks the effects of the naturally occurring chemical histamine in your body.
Promethazine may also be used for purposes not listed in this medication guide.
Promethazine should not be given to a child younger than 2 years old. Promethazine can cause severe breathing problems or death in very young children.
Before taking this medicine
Promethazine should not be given to a child younger than 2 years old. Promethazine can cause severe breathing problems or death in very young children. Carefully follow your doctor's instructions when giving this medicine to a child of any age.
You should not take this medicine if you are allergic to promethazine or to similar medicines such as chlorpromazine, fluphenazine, mesoridazine, perphenazine, prochlorperazine, thioridazine, or trifluperazine.
To make sure promethazine is safe for you, tell your doctor if you have:
a sulfite allergy;
a history of seizures;
a weak immune system (bone marrow depression);
enlarged prostate or problems with urination;
stomach ulcer or obstruction;
heart disease or high blood pressure;
adrenal gland tumor (pheochromocytoma);
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.
It is not known whether promethazine 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 promethazine passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.
How should I take promethazine?
Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Promethazine is often taken at bedtime or before meals. For motion sickness, promethazine is usually started within 1 hour before traveling. When used for surgery, promethazine is usually taken the night before the surgery.
How often you take this medicine and the timing of your dose will depend on the condition being treated.
Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
If a child is using this medicine, tell your doctor if the child has any changes in weight. Promethazine doses are based on weight in children, and any changes may affect your child's dose.
Call your doctor if your symptoms do not improve, or if they get worse while using promethazine.
This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using promethazine.
Store at room temperature away from moisture, heat, and light.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include overactive reflexes, loss of coordination, severe drowsiness or weakness, fainting, dilated pupils, weak or shallow breathing, or seizure (convulsions).
What should I avoid while taking promethazine?
This medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert. Avoid getting up too fast from a sitting or lying position, or you may feel dizzy. Get up slowly and steady yourself to prevent a fall.
Drinking alcohol can increase certain side effects of promethazine.
Avoid exposure to sunlight or tanning beds. Promethazine can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.
Promethazine side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using promethazine and call your doctor at once if you have:
severe drowsiness, weak or shallow breathing;
a light-headed feeling, like you might pass out;
fast or slow heartbeats;
jaundice (yellowing of the skin or eyes);
uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
easy bruising or bleeding (nosebleeds, bleeding gums);
severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.
Side effects such as confusion and severe drowsiness may be more likely in older adults.
Common side effects may include:
ringing in your ears;
dry mouth; or
tired feeling, sleep problems (insomnia).
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.
See also: Side effects (in more detail)
What other drugs will affect promethazine?
Using this medicine with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before taking promethazine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.
Other drugs may interact with promethazine, 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.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 6.02.
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