Promethazine and Dextromethorphan

Generic name: Promethazine and Dextromethorphan [ proe-METH-a-zeen-& deks-troe-meth-OR-fan ]
Drug class: Upper respiratory combinations

Medically reviewed by Drugs.com. Last updated on Oct 26, 2022.

Uses of Promethazine and Dextromethorphan:

• 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 my doctor BEFORE I take Promethazine and Dextromethorphan?

• If you have an allergy to dextromethorphan, promethazine, or any other part of promethazine and dextromethorphan.
• If you are allergic to promethazine and dextromethorphan; any part of promethazine and dextromethorphan; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
• If you have any of these health problems: Asthma or other breathing problems like COPD (chronic obstructive pulmonary disease) or sleep apnea (breathing problems during sleep).
• If you have a cough with a lot of mucus.
• If you have a long-term cough caused by smoking or being around smoke, or lung problems like asthma or emphysema.
• If you have taken certain drugs for depression or Parkinson's disease in the last 14 days. This includes isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline. Very high blood pressure may happen.

This is not a list of all drugs or health problems that interact with promethazine and dextromethorphan.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take promethazine and dextromethorphan with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Promethazine and Dextromethorphan?

• Tell all of your health care providers that you take promethazine and dextromethorphan. This includes your doctors, nurses, pharmacists, and dentists.
• Do not take more than what your doctor told you to take. Taking more than you are told may raise your chance of very bad side effects.
• Do not take promethazine and dextromethorphan for longer than you were told by your doctor.
• Avoid driving and doing other tasks or actions that call for you to be alert or have clear eyesight until you see how promethazine and dextromethorphan affects you.
• This medicine may affect certain lab tests. Tell all of your health care providers and lab workers that you take promethazine and dextromethorphan.
• If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
• This medicine may cause the results of some pregnancy tests to be wrong. Talk with the doctor.
• Talk with your doctor before you drink alcohol or use other drugs and natural products that slow your actions.
• You may get sunburned more easily. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.
• This medicine may raise the chance of seizures in some people, including people who have had seizures in the past. Talk to your doctor to see if you have a greater chance of seizures while taking promethazine and dextromethorphan.
• If you are 65 or older, use promethazine and dextromethorphan with care. You could have more side effects.
• Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using promethazine and dextromethorphan while you are pregnant.
• Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.

How is this medicine (Promethazine and Dextromethorphan) best taken?

Use promethazine and dextromethorphan as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Take with or without food. Take with food if it causes an upset stomach.
• Measure liquid doses carefully. Use the measuring device that comes with promethazine and dextromethorphan. If there is none, ask the pharmacist for a device to measure promethazine and dextromethorphan.

What do I do if I miss a dose?

• If you take promethazine and dextromethorphan on a regular basis, take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.
• Many times promethazine and dextromethorphan is taken on an as needed basis. Do not take more often than told by the doctor.

What are some side effects that I need to call my 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 doctor or get medical help right away if you have 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.
• Feeling very tired or weak.
• Trouble controlling body movements, twitching, change in balance, trouble swallowing or speaking.
• 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.
• Not able to sleep.
• Yellow skin or eyes.
• A very bad and sometimes deadly health problem called neuroleptic malignant syndrome (NMS) may happen. Call your doctor right away if you have any fever, muscle cramps or stiffness, dizziness, very bad headache, confusion, change in thinking, fast heartbeat, heartbeat that does not feel normal, or are sweating a lot.
• This medicine may cause very bad and sometimes deadly breathing problems. Call your doctor right away if you have slow, shallow, or trouble breathing.
• Low white blood cell counts have rarely happened with promethazine and dextromethorphan. This may lead to a higher chance of getting an infection. Tell your doctor if you have ever had a low white blood cell count. Call your doctor right away if you have signs of infection like fever, chills, or sore throat.

What are some other side effects of Promethazine and Dextromethorphan?

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

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

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

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If OVERDOSE is suspected:

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.

How do I store and/or throw out Promethazine and Dextromethorphan?

• Store at room temperature.
• Protect 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.

Consumer Information Use and Disclaimer

• If your symptoms or health problems do not get better or if they become worse, call your doctor.
• Do not share your drugs with others and do not take anyone else's drugs.
• Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about promethazine and dextromethorphan, please talk with your 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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer