How Long After Zyrtec Can You Take Benadryl?
In our latest question and answer, the pharmacist discusses how long after taking Zyrtec you can safely take Benadryl.
I’m having an allergic reaction from going through musty files from last night for 2:5 hours. My nose wouldnt stop running all day today. I took a dissolvable Zyrtec at 5:30 PM, can I now take a Benadryl tonight at 11:30 PM?
Taking Zyrtec and Benadryl at the same time should only be done with caution due to the risk of increased adverse events. Both medications are antihistamines and taking them together greatly increases the risk of side effects such as:
- Dry mouth
- Dry eyes
Taking Benadryl After Zyrtec
Zyrtec (cetirizine) is a "second-generation" antihistamine, with a duration of action around 24 hours. To best avoid additive side effects, Benadryl should ideally be taken 24 hours after Zyrtec. However, taking Benadryl if you are having an allergic reaction is generally considered safe, even if you are already taking an antihistamine for your daily allergies. While you may be at an increased risk of certain side effects (such as drowsiness), they typically are mild in severity and the benefits of taking Benadryl to lessen the effects of an allergic reaction outweighs the risk of the mild side effects.
In addition, your doctor may recommend to take you take Benadryl for allergic symptoms that are severe, and don't seem to lessen after taking your Zyrtec. Benadryl tends to have better anti-inflammatory and anti-pruritic (i.e. anti-itch) effects than other antihistamines so use is often warranted. In general, they just shouldn't be taken together on a daily basis, only as needed intermittently.