Does Zyrtec-D Cause Drowsiness?
In our latest question and answer, the pharmacist discusses whether or not Zyrtec-D causes drowsiness.
I just got some Zyrtec-D from my pharmacy and want to know if it will cause drowsiness?
Jul 01, 2021- Zyrtec-D combines cetirizine, which can cause drowsiness in about 10-15% of adults, and pseudoephedrine, a stimulant that tends to counteract drowsiness.
- Drowsiness from Zyrtec-D is less common than with cetirizine alone because the stimulant ingredient helps offset the drowsy effects of the antihistamine.
- It's a good idea to take your first dose at home to see how the medication affects you personally.
Hi Gail and thank you for writing to us. Zyrtec-D is actually a combination medication. It combines two different medications, cetirizine and pseudoephedrine. Let’s look at these individually.
Cetirizine
Cetirizine (or by the brand Zyrtec) is a “second generation” antihistamine. It works by binding to histamine receptors in the body so that histamine can’t bind to them. This helps to reduce the symptoms typically caused by allergies.
Zyrtec-D is generally well tolerated and lasts about 24 hours per dose. It is often advertised as non-drowsy but about 10-15% of adults will experience drowsiness while taking this according to published drug information. Have you ever taken regular cetirizine before? If regular cetirizine makes you drowsy, then Zyrtec-D may be more likely to than other antihistamine-decongestant options. Pseudoephedrine
Pseudoephedrine is a behind the counter sympathomimetic drug, or a stimulant drug that mimics the sympathetic nervous system.
It helps to clear sinus congestion but at the same time, tends to increase heart rate and blood pressure. Since it is a stimulant, some people will experience a bit of jitteriness when they take the medication. If you have blood pressure or any heart conditions, you should probably check with your physician before you begin taking anything with pseudoephedrine in it.
Will It Make You Drowsy?
Having given a brief description of each of these, you can see they have somewhat opposing side effects...one can make you tired, and the other has a mild stimulant effect.
Overall, drowsiness after Zyrtec-D isn't that common (due to the addition of pseudoephedrine). There is certainly a chance it may cause drowsiness in some people, but it would be less likely than if you were to take Zyrtec on its own. I would recommend taking your first dose at home, just in case it does make you a bit drowsy.
I hope this helps! Feel free to write back to us in the future!
References & sources
- Sedation with “non-sedating” antihistamines: four prescription-event monitoring studies in general practice — The British Medical Journal
- Pseudoephedrine — PubChem
Glossary — Terms in This Answer
- Antihistamine
- A medication that blocks histamine, a chemical in your body that causes allergy symptoms.
- Histamine receptors
- Binding sites on cells where histamine attaches and triggers allergic reactions.
- Cetirizine
- A second-generation antihistamine medication used to treat allergy symptoms.
- Pseudoephedrine
- A decongestant stimulant drug that helps clear sinus congestion by mimicking the sympathetic nervous system.
- Sympathomimetic
- A drug that stimulates the sympathetic nervous system, which increases heart rate and blood pressure.
- Sympathetic nervous system
- The part of your nervous system that controls 'fight or flight' responses, increasing heart rate and blood pressure.
- Combination medication
- A single drug product that contains two or more active ingredients.
- Sinus congestion
- Blockage and swelling in the nasal passages and sinuses that makes breathing difficult.
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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