Medically reviewed on June 26, 2018
What is rectal Phenadoz?
Phenadoz is in a group of drugs called phenothiazines (FEEN-oh-THYE-a-zeens). It works by changing the actions of chemicals in your brain. This medicine also acts as an antihistamine. It blocks the effects of the naturally occurring chemical histamine in your body.
Phenadoz may also be used for other purposes not listed in this medication guide.
Phenadoz should not be used in a child younger than 2 years old. This medicine can cause severe breathing problems or death in a child younger than 2.
Before taking this medicine
Phenadoz should not be used in a child younger than 2 years old. This medicine can cause severe breathing problems or death in a child younger than 2. Carefully follow your doctor's instructions when giving Phenadoz to a child of any age.
You should not use this medicine if you are allergic to Phenadoz or to similar medicines such as chlorpromazine, fluphenazine, mesoridazine, perphenazine, prochlorperazine, thioridazine, or trifluperazine.
To make sure rectal Phenadoz 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 Phenadoz or any other phenothiazine.
FDA pregnancy category C. It is not known whether Phenadoz 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 use rectal Phenadoz?
Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.
This medicine comes with patient instructions for using the rectal suppository. Follow these directions carefully. Ask your doctor or pharmacist if you have any questions.
Do not take Phenadoz by mouth. It is for use only in your rectum.
Try to empty your bowel and bladder just before using the Phenadoz suppository.
Remove the outer wrapper from the suppository before inserting it. Avoid handling the suppository too long or it will melt in your hands.
For best results from the suppository, lie down after inserting it and hold in the suppository for a few minutes. The suppository will melt quickly once inserted and you should feel little or no discomfort while holding it in. Avoid using the bathroom just after you have inserted the suppository.
Call your doctor if your symptoms do not improve, or if they get worse while using Phenadoz.
This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using rectal Phenadoz.
Store the rectal suppositories in the refrigerator but do not allow them to freeze.
What happens if I miss a dose?
Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use 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 using rectal Phenadoz?
Phenadoz 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. Phenadoz can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.
Rectal Phenadoz side effects
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.
Stop using Phenadoz 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);
sudden weakness or ill feeling, fever, chills, sore throat, mouth sores, red or swollen gums, trouble swallowing; or
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. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect rectal Phenadoz?
Using Phenadoz with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before using Phenadoz 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: 4.01.
More about Phenadoz (promethazine)
- Phenadoz Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- Support Group
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- Drug class: antihistamines