Can You Take Benadryl And Robitussin Together?
In our latest question and answer, the pharmacist discusses whether or not Benadryl (diphenhydramine) can be taken with Robitussin.
Is it okay to take Benadryl and Robitussin together?
May 23, 2022- Benadryl and most Robitussin products can be safely taken together because they don't interact with each other.
- Avoid combining Benadryl with Robitussin Night Time Cough DM or Robitussin Severe Multi-Symptom Cough Cold & Flu Nighttime since these products already contain an antihistamine and taking both could cause too much drowsiness and side effects like dry mouth and constipation.
- Always check the ingredient list on your specific Robitussin product to make sure it doesn't already contain an antihistamine before adding Benadryl.
Benadryl (diphenhydramine) can be safely taken with Robitussin (dextromethorphan) as there is no interaction between the two drugs.
I do want to point out that although "Robitussin" is generally associated with the drug dextromethorphan, Robitussin is itself a brand name.
A variety of over-the-counter cough/cold products use that name, many of which contain different ingredients.
Below, I list the most common Robitussin products, their ingredients, and whether or not they can be used with Benadryl.
Robitussin Family Of Products With Benadryl
Robitussin Cough & Chest Congestion DM
- Dextromethorphan (cough suppressant)
- Guaifenesin (expectorant)
Robitussin Cough & Chest Congestion DM is safe to take with Benadryl and there is no interaction between the two.
Robitussin Night Time Cough DM
- Dextromethorphan (cough suppressant)
- Doxylamine (sedating antihistamine)
Benadryl should not be taken with Robitussin Night Time Cough DM.
This Robitussin product already contains a sedating, first-generation antihistamine (doxylamine) and therefore Benadryl should not be needed.
Taking both together may cause excess sedation and side effects such as dry mouth, dry eyes, constipation, etc.
Robitussin 12 Hour Cough Relief
- Dextromethorphan (cough suppressant)
Benadryl is safe to take with Robitussin 12 Hour Cough Relief
Robitussin Severe Multi-Symptom Cough Cold & Flu
- Acetaminophen (analgesic)
- Dextromethorphan (cough suppressant)
- Guaifenesin (expectorant)
- Phenylephrine (nasal decongestant)
Benadryl is safe to take with Robitussin Severe Multi-Symptom Cough Cold & Flu.
Robitussin Severe Multi-Symptom Cough Cold & Flu Nighttime
- Acetaminophen (analgesic)
- Diphenhydramine (sedating antihistamine)
- Phenylephrine (nasal decongestant)
Benadryl should not be taken with Robitussin Severe Multi-Symptom Cough Cold & Flu Nighttime. The product already contains Benadryl (diphenhydramine).
Robitussin Severe Cough & Sore Throat
- Acetaminophen (analgesic)
- Dextromethorphan (cough suppressant)
Benadryl is safe to take with Robitussin Severe Cough & Sore Throat
Robitussin Multi-Symptom Cold CF
- Dextromethorphan (cough suppressant)
- Guaifenesin (expectorant)
- Phenylephrine (nasal decongestant)
Benadryl is safe to take Robitussin Multi-Symptom Cold CF.
Summary
As shown above, Benadryl (diphenhydramine) is safe to take with most Robitussin products. Benadryl should only be avoided with Robitussin products that already contain an antihistamine. Robitussin products that contain an antihistamine include:
- Robitussin Severe Multi-Symptom Cough Cold & Flu Nighttime
- Robitussin Night Time Cough DM
Benadryl is safe to take with all other Robitussin products.
References & sources
- Diphenhydramine Monograph — https://pubchem.ncbi.nlm.nih.gov/compound/Diphenhydramine
- Dextromethorphan Monograph — https://pubchem.ncbi.nlm.nih.gov/compound/Dextromethorphan
- Doxylamine Monograph — https://pubchem.ncbi.nlm.nih.gov/compound/Doxylamine
- Acetaminophen Monograph — https://pubchem.ncbi.nlm.nih.gov/compound/Acetaminophen
- Guaifenesin Monograph — https://pubchem.ncbi.nlm.nih.gov/compound/Guaifenesin
- Phenylephrine Monograph — https://pubchem.ncbi.nlm.nih.gov/compound/Phenylephrine
Glossary — Terms in This Answer
- Diphenhydramine
- An antihistamine medication that blocks histamine to relieve allergy symptoms and is the active ingredient in Benadryl.
- Dextromethorphan
- A cough suppressant that reduces the urge to cough by acting on the cough center in the brain.
- Expectorant
- A type of medication that helps thin mucus to make coughs more productive and easier to clear from the airways.
- Guaifenesin
- An expectorant ingredient found in cough medicines that helps thin and clear mucus from the respiratory tract.
- Antihistamine
- A medication that blocks the effects of histamine to relieve allergy symptoms, itching, and sneezing.
- Acetaminophen
- A pain reliever and fever reducer commonly used to treat aches, pains, and fevers.
- Phenylephrine
- A nasal decongestant medication that narrows blood vessels to relieve nasal congestion and stuffiness.
- Doxylamine
- A sedating antihistamine used in nighttime cold and cough products to help with symptom relief and sleep.
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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