Taking Promethazine With Codeine With NyQuil
In our latest question and answer, the pharmacist discusses whether or not it is safe to promethazine with codeine and NyQuil at the same time.
I took 5ml of promethazine w/ codeine. Can I take a dose of NyQuil with it?
Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist Staff
Last updated Oct 26, 2022
- Combining Promethazine with codeine and NyQuil should generally be avoided due to the risk of additive side effects.
It is generally not recommended to take promethazine with codeine and NyQuil together, for numerous reasons.
Both Drugs Contain Antihistamines
First and foremost, NyQuil contains the antihistamine doxylamine, which is similar to Benadryl in that it is classified as a sedating "first-generation" antihistamine.
Promethazine is also an antihistamine, with very similar effects to doxylamine, and may even be more sedating for some individuals.
Promethazine with doxylamine represents a double dose of sedating antihistamines and is considered a duplicate therapy. You will likely feel drowsy or more tired when taking these drugs together. In addition, you may experience other side effects including:
- Difficulty with urination
- Dry mouth and eyes
- Changes in vision
- Fast heartbeat
Combining Codeine With Multiple Antihistamines Increases The Risk Of Side Effects
Not only will taking two different antihistamines likely cause some of the side effects mentioned in the section above, promethazine with codeine, of course, contains codeine. Adding on the doxylamine from NyQuil will further increase the risk of serious side effects, such as respiratory depression.
Last but not least, both promethazine and codeine and NyQuil contain alcohol. While it isn't much alcohol, you still would be combining three drugs (i.e., doxylamine, promethazine, and ethanol) that are considered CNS (central nervous system) depressants.
The drugs should be avoided with one another unless your doctor has directed you otherwise.
Although the duration of action of these drugs can vary by individual, each lasts around 4 to 6 hours and should be separated by at least that amount of time.
Thanks for reaching out to us!
- Dr. Brian Staiger, PharmD
- 3147 views
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