Taking Promethazine With Codeine With NyQuil
In our latest question and answer, the pharmacist discusses whether or not it is safe to take 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?
Oct 26, 2022- Do not take promethazine with codeine and NyQuil together because both contain sedating antihistamines that can cause excessive drowsiness and increase the risk of serious side effects like respiratory depression.
- NyQuil and promethazine with codeine both contain central nervous system depressants including alcohol, which when combined can be dangerous.
- If you need to take these medications, separate them by at least 4 to 6 hours and only do so under your doctor's direction.
Answer
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:
- Constipation
- Dizziness
- Difficulty with urination
- Dry mouth and eyes
- Changes in vision
- Fast heartbeat
- Confusion
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.
Final Words
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.
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References & sources
Glossary — Terms in This Answer
- Antihistamine
- A medication that blocks histamine, a chemical in the body that causes allergy symptoms and sedation.
- Doxylamine
- A sedating antihistamine commonly found in over-the-counter cold and sleep medicines like NyQuil.
- Promethazine
- A prescription antihistamine medication that is often combined with codeine and has strong sedating effects.
- Codeine
- An opioid pain reliever and cough suppressant that can be found in some prescription cough syrups.
- Duplicate therapy
- Taking two or more medications that work in the same way, which can increase the risk of side effects.
- Respiratory depression
- A serious condition where breathing becomes dangerously slow or shallow.
- Central nervous system depressants
- Substances that slow down brain and nerve activity, causing drowsiness and reduced alertness.
- Duration of action
- The length of time a medication remains active and effective in the body.
Dr. Brian Staiger, PharmD
Doctor of Pharmacy, board certified clinical pharmacist (BCPS), American Herbalist Guild, Medication Therapy Management certified
Brian Staiger, PharmD, BCPS, is a licensed pharmacist with more than 13 years of experience across retail pharmacy, clinical pharmacy, medication safety, pharmacy program development, and healthcare administration. He is the founder of HelloPharmacist.com, where he helps patients...
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