Promethazine and Dextromethorphan

This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Warning

  • Do not give this drug to a child younger than 2 years of age. It may cause very bad and sometimes deadly breathing problems.
  • Use with care in children 2 years of age and older. Talk with the doctor.
  • Before your child takes this drug, tell the doctor if your child is taking any drugs that can cause breathing problems. There are many drugs that can do this. Ask the doctor or pharmacist if you are not sure.

What is this drug used for?

  • It is used to relieve coughing.
  • It is used to ease allergy signs.
  • It is used to ease cold signs.

What do I need to tell the doctor BEFORE my child takes this drug?

  • If your child is allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell the doctor about the allergy and what signs your child had.
  • If your child has any of these health problems: Asthma or other breathing problems like COPD (chronic obstructive pulmonary disease) or sleep apnea (breathing problems during sleep).
  • If your child has any of these health problems: Cough with a lot of mucus, a long-term cough caused by smoking or being around smoke, or lung problems like asthma.
  • If your child has taken certain drugs for depression or certain other health problems in the last 14 days. This includes isocarboxazid, phenelzine, or tranylcypromine. Very high blood pressure may happen.
  • If your child is taking any of these drugs: Linezolid or methylene blue.

This is not a list of all drugs or health problems that interact with this drug.

Tell the doctor and pharmacist about all of your child’s drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe to give this drug with all of your child’s other drugs and health problems. Do not start, stop, or change the dose of any drug your child takes without checking with the doctor.

What are some things I need to know or do while my child takes this drug?

  • Tell all of your child’s health care providers that your child is taking this drug. This includes your child’s doctors, nurses, pharmacists, and dentists.
  • Do not give your child more of this drug than what the doctor told you to give. Giving more of this drug than you are told may raise the chance of severe side effects.
  • Do not have your child use longer than you have been told by your child’s doctor.
  • Have your child avoid tasks or actions that call for alertness until you see how this drug affects your child. These are things like riding a bike, playing sports, or using items such as scissors, lawnmowers, electric scooters, toy cars, or motorized vehicles.
  • This drug may affect certain lab tests. Tell all of your child’s health care providers and lab workers that your child takes this drug.
  • If your child has high blood sugar (diabetes), you will need to watch your child’s blood sugar closely.
  • Alcohol may interact with this drug. Be sure your child does not drink alcohol.
  • Talk with your child’s doctor before your child uses marijuana, other forms of cannabis, or prescription or OTC drugs that may slow your child’s actions.
  • Your child may get sunburned more easily. Avoid lots of sun, sunlamps, and tanning beds. Use sunscreen and dress your child in clothing and eyewear that protects from the sun.
  • This drug may raise the chance of seizures in some people, including people who have had seizures in the past. Talk to the doctor to see if your child has a greater chance of seizures while taking this drug.

If your child is or may be sexually active:

  • This drug may cause the results of some pregnancy tests to be wrong. Talk with the doctor.

If your child is pregnant or breast-feeding a baby:

  • Talk with the doctor if your child is pregnant, becomes pregnant, or is breast-feeding a baby. You will need to talk about the benefits and risks to your child and the baby.

What are some side effects that I need to call my child’s doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your child’s doctor or get medical help right away if your child has any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of high or low blood pressure like very bad headache or dizziness, passing out, or change in eyesight.
  • Fast or slow heartbeat.
  • Trouble passing urine.
  • Trouble controlling body movements, twitching, change in balance, trouble swallowing or speaking.
  • Shakiness.
  • Hallucinations (seeing or hearing things that are not there).
  • Mood changes.
  • Ringing in ears.
  • Seizures.
  • Any unexplained bruising or bleeding.
  • Change in eyesight.
  • Feeling nervous and excitable.
  • Trouble sleeping.
  • Yellow skin or eyes.
  • A very bad and sometimes deadly health problem called neuroleptic malignant syndrome (NMS) may happen. Call your child’s doctor right away if your child has any fever, muscle cramps or stiffness, dizziness, very bad headache, confusion, change in thinking, fast heartbeat, heartbeat that does not feel normal, or is sweating a lot.
  • This drug may cause very bad and sometimes deadly breathing problems. Call the doctor right away if your child has slow, shallow, or trouble breathing.
  • Low white blood cell counts have rarely happened with this drug. This may lead to a higher chance of getting an infection. Tell your child’s doctor if your child has ever had a low white blood cell count. Call your child’s doctor right away if your child has signs of infection like fever, chills, or sore throat.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your child’s doctor or get medical help if any of these side effects or any other side effects bother your child or do not go away:

  • Feeling dizzy, sleepy, tired, or weak.
  • Dry mouth.
  • Upset stomach or throwing up.

These are not all of the side effects that may occur. If you have questions about side effects, call your child’s doctor. Call your child’s doctor for medical advice about side effects.

You may report side effects to your national health agency.

How is this drug best given?

Give this drug as ordered by your child’s doctor. Read all information given to you. Follow all instructions closely.

  • Give this drug with or without food. Give with food if it causes an upset stomach.
  • Measure liquid doses carefully. Use the measuring device that comes with this drug. If there is none, ask the pharmacist for a device to measure this drug.
  • Do not use a household teaspoon or tablespoon to measure this drug. Doing so could lead to the dose being too high.

What do I do if my child misses a dose?

  • If your child takes this drug on a regular basis, give a missed dose as soon as you think about it.
  • If it is close to the time for your child’s next dose, skip the missed dose and go back to your child’s normal time.
  • Do not give 2 doses at the same time or extra doses.
  • Many times this drug is given on an as needed basis. Do not give to your child more often than told by the doctor.

How do I store and/or throw out this drug?

  • Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

General drug facts

  • If your child’s symptoms or health problems do not get better or if they become worse, call your child’s doctor.
  • Do not share your child’s drug with others and do not give anyone else’s drug to your child.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your child’s doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider’s examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.

Last Reviewed Date

2023-04-12

Copyright

© 2024 UpToDate, Inc. and its affiliates and/or licensors. All rights reserved.

Last Updated

Monday, December 12, 2022