Regin asked
Is it ok to take a Zyrtec-D and a Zyrtec in the same day?
At a glance
- Zyrtec and Zyrtec-D both contain cetirizine, and should not be taken at the same time.
- Zyrtec (10 mg) has a duration of action of 24 hours, so you likely won't need to take Zyrtec and Zyrtec-D the same day.
Answer
Zyrtec (cetirizine) and Zyrtec-D (cetirizine; pseudoephedrine) should not be taken at the same time, even the same day. Both products contain the antihistamine Zyrtec (cetirizine) and taking both together would be considered a therapeutic duplication.
Given the fact that cetirizine has a 24-hour duration of action, there would be no need to take both products.
Zyrtec-D contains cetirizine and pseudoephedrine (brand name Sudafed). If you are looking for a decongestant in addition to an antihistamine, you should take Zyrtec-D. If you are just looking to take an antihistamine, you should simply take Zyrtec.
The one exception to the above recommendation is based on which Zyrtec-D product you use. Zyrtec-D comes in two different formulations:
- Zyrtec-D 12 Hour (cetirizine 5 mg/pseudoephedrine 120 mg)
- Zyrtec-D 24 Hour (cetirizine 10 mg/pseudoephedrine 240 mg)
Zyrtec-D 12 Hour has a duration of around 12 hours. After that 12 hour period, you can safely take another Zyrtec-D 12 Hour tablet or a 'regular' Zyrtec tablet.
So to answer the question specifically regarding whether or not Zyrtec and Zyrtec-D can be taken the same day, the answer is yes but only in the situation where you take Zyrtec-D 12 Hour first then "regular" Zyrtec at least 12 hours later.
About Zyrtec
Zyrtec (cetirizine) is a "second-generation" antihistamine, indicated for:
- Treatment and prevention of perennial allergies
- Treatment and prevention of seasonal allergies
- Urticaria (hives)
Zyrtec, although a "second-generation" antihistamine, has a higher incidence of sedation (~10%) than others in the class, including Allegra (fexofenadine) and Claritin (loratadine). It is not considered non-drowsy. Nevertheless, it still causes less sedation than older, first-generation antihistamines such as Benadryl.
Zyrtec is taken once daily and has an onset of action for around one hour.
About Pseudoephedrine
Pseudoephedrine is an oral nasal decongestant that is also used to relieve sinus pressure in adults and children 4 years of age and older. Unlike many nasal decongestant sprays, Sudafed does not typically cause rebound congestion and can often be safely taken for more than 3 days.
As pseudoephedrine is commonly diverted for use in the illegal synthesis of methamphetamine, a 2005 law was passed (Combat Methamphetamine Epidemic Act) which governs the sale and purchase of all OTC products containing pseudoephedrine.
Pseudoephedrine is available in a variety of formulations, including as a single ingredient in both immediate and extended-release products, as well as in combination with other ingredients, such as with an antihistamine (e.g. Zyrtec-D).
References
- CMEA (Combat Methamphetamine Epidemic Act of 2005). DEA
- Cetirizine Monograph. ClinicalKey
- Pseudoephedrine Monograph. ClinicalKey
