This article describes possible interactions with promethazine oral tablet. Interactions can cause a drug to have a different effect on the body than expected. Interactions can occur due to medications, alcohol, or certain health conditions.
Promethazine comes as tablets that you swallow. It’s also available as a liquid solution that’s injected into your muscle or vein, a syrup that you swallow, and a suppository that’s inserted in the rectum. Interactions of promethazine may vary depending on the form of promethazine you’re prescribed.
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Other drugs and promethazine
The drugs in the list below may interact with promethazine oral tablet. This article doesn’t include all drugs that may interact with promethazine.
Drug classes or drugs that may interact with promethazine oral tablet include:
- sedatives:
- drug examples: zolpidem (Ambien), eszopiclone (Lunesta)
- what might happen: can increase the sedative effect of promethazine and the sedative
- barbiturates:
- drug example: phenobarbital
- what might happen: can increase the sedative effect of promethazine and the barbiturate
- opioids:
- muscle relaxants:
- drug examples: baclofen, cyclobenzaprine, methocarbamol (Robaxin), tizanidine (Zanaflex)
- what might happen: can increase the sedative effect of promethazine and the muscle relaxant
- benzodiazepines:
- drug examples: alprazolam (Xanax), lorazepam (Ativan)
- what might happen: can increase the sedative effect of promethazine and the benzodiazepine
- tricyclic antidepressants:
- drug examples: amitriptyline (Elavil), nortriptyline (Pamelor), doxepin
- what might happen: can increase the sedative effect of promethazine and the tricyclic antidepressant
- monoamine oxidase inhibitors:
- drug examples: phenelzine (Nardil), isocarboxazid (Marplan)
- what might happen: can increase the risk of side effects of promethazine
- anticholinergics:
- drug examples: diphenhydramine (Benadryl), oxybutynin (Ditropan), dicyclomine, fesoterodine (Toviaz)
- what might happen: can increase the risk of side effects of promethazine and the anticholinergic drug
- epinephrine:
- what might happen: can make epinephrine less effective than usual
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Get free cardWhen to avoid promethazine
Certain health conditions or other factors could increase some risks with promethazine oral tablet. Because of this, doctors may not prescribe promethazine in these cases. These health conditions or other factors are called contraindications.
Here’s a list of contraindications for promethazine oral tablet:
- Children under 2 years of age: If your child is under 2 years old, taking promethazine oral tablet may cause life threatening respiratory depression (a disorder causing slow, shallow breathing that may be life threatening).
- Unconsciousness or coma: If you’re in a coma, taking promethazine oral tablet may further weaken your brain activity.
- Treatment of lower respiratory tract symptoms, including asthma: If you have lower respiratory tract symptoms, including asthma, promethazine should not be used as a treatment. Taking promethazine oral tablet may worsen your symptoms and cause respiratory depression.
- Past allergic reaction to promethazine: If you’ve ever had an allergic reaction to promethazine oral tablet, taking it again may cause another allergic reaction.
Before you start taking promethazine, tell your doctor if anything listed above relates to you. They can recommend whether you should take promethazine.
Alcohol and promethazine
Promethazine oral tablet is known to interact with alcohol.
Taking promethazine oral tablet and drinking alcohol may cause:
- drowsiness
- difficulty focusing, thinking, and reacting
- problems with coordination and balance
If you drink alcohol and have concerns about avoiding it while taking promethazine oral tablet, talk with your doctor.
Other interactions and promethazine
Interactions can occur with supplements, foods, vaccines, and some lab tests. Below you can learn whether promethazine oral tablet has these interactions.
The information below doesn’t include all other possible interactions with promethazine.
Promethazine and supplements
Before taking promethazine oral tablet, tell your doctor and pharmacist about any herbs you take, as well as vitamins and supplements. Doing so may help you avoid interactions.
Promethazine oral tablet may interact with melatonin supplements. These are supplements that help manage sleep problems.
Taking promethazine and melatonin may lead to more intense and long lasting drowsiness. It can also worsen dizziness and coordination and make it more difficult to think, focus, and react.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Promethazine interactions with herbs
Promethazine oral tablet may interact with St. John’s wort. This herb is often used to help with symptoms of depression.
Taking promethazine and St. John’s wort may lead to heart and blood vessel problems.
Because of this, ask your doctor or pharmacist before using any of these products while taking promethazine oral tablet.
Promethazine interactions with vitamins
Promethazine oral tablet isn’t known to interact with any vitamins. But this doesn’t mean interactions with vitamins can’t happen or won’t be identified later.
Because of this, ask your doctor or pharmacist before using any of these products while taking promethazine oral tablet.
Promethazine and food
Promethazine oral tablet isn’t known to interact with foods. But this doesn’t mean interactions with foods can’t happen or won’t be identified later.
Because of this, talk with your doctor or pharmacist about what foods you should avoid while taking promethazine oral tablet.
Promethazine and vaccines
Promethazine oral tablet isn’t known to interact with any vaccines. But this doesn’t mean interactions with vaccines can’t happen or won’t be identified later.
Because of this, talk with your doctor or pharmacist before receiving any vaccines while taking promethazine oral tablet.
Promethazine and lab tests
Promethazine oral tablet may interact with a urine test used to check for pregnancy. Taking promethazine and having this test may lead to false-positive or false-negative results.
Promethazine oral tablet may also interact with a glucose tolerance test (a test used to check your blood sugar levels). Taking promethazine and having this test may raise blood sugar levels.
Because of this, talk with your doctor or pharmacist before having any tests while taking promethazine oral tablet.
Promethazine and cannabis or CBD
Reports have shown cannabis (commonly called marijuana) and cannabis products may interact with promethazine. Cannabidiol (CBD) is an example of a cannabis product.
Taking promethazine and cannabis may lead to extreme sleepiness, problems with concentration and coordination, and increased effects of cannabis.
Before you take promethazine, tell your doctor and pharmacist if you use cannabis. Doing so may help prevent possible interactions.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Health factors and promethazine
Certain medical conditions or other health factors may increase the risk of interactions with promethazine oral tablet. Keep in mind that interactions could lead to side effects or affect how well the drug works. Before taking promethazine, tell your doctor about your health history. They’ll determine whether promethazine is right for you.
These health conditions or other factors might interact with promethazine oral tablet:
- angle-closure glaucoma
- enlarged prostate
- intestinal blockage
- bladder problems
- bone marrow disease
- heart disease
- liver problems
- sleep apnea
- seizures
- pregnancy or breastfeeding
- past allergic reaction to promethazine
- being age 65 years or older
- being under 2 years of age*
- lung or breathing problems*
* To learn more about this interaction, see the “When to avoid promethazine” section above.
Preventing promethazine interactions
You may be able to help avoid certain interactions with promethazine oral tablet. Before taking this drug, you may want to discuss possible interactions with your doctor and pharmacist.
Things to consider include:
- Whether you drink alcohol or use cannabis.
- Other medications and herbs you take, as well as vitamins and supplements. Your doctor or pharmacist can help you fill out a medication list.
- What to do if you’re prescribed a new drug while taking promethazine oral tablet.
Taking promethazine exactly as prescribed can also help prevent interactions.
What to ask your doctor
If you have questions about promethazine and possible interactions, talk with your doctor.
Questions you may want to ask your doctor include:
- Could I still take promethazine oral tablet even if it interacts with a health condition I have?
- Do I need to take my medications at different times throughout the day to avoid interactions?
- Does the dose of promethazine oral tablet affect my risk of interactions?
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.