Can you donate blood if you take antihistamines?
Yes in most cases. Common antihistamines such as loratadine (Claritin), cetirizine (Zyrtec) and diphenhydramine (Benadryl) do not stop you from donating if you feel well.
Antihistamines are widely used for hay fever, hives and other allergies. Over-the-counter medications like these usually do not prevent you from giving blood.
Common examples
| Medicine | Drowsiness | Donation |
|---|---|---|
| Loratadine (Claritin) | No | Generally no restriction |
| Cetirizine (Zyrtec) | Mild or none | Generally no restriction |
| Fexofenadine (Allegra) | No | Generally no restriction |
| Diphenhydramine (Benadryl) | Yes | Usually fine, but avoid if drowsy |
What matters more
- If your allergies are under control and you feel well, you can generally donate
- If you have an active allergic reaction, wheezing or shortness of breath, you should wait
- If you have hives or an active reaction right now, the screener will evaluate you
Tip
Mention what you took at screening. If a sedating antihistamine makes you drowsy, it is a good idea to wait until the effect has passed.
This information is general and does not replace advice from a health professional. Your eligibility is always decided at the donor screening on the day of donation. Rules change, so confirm with the American Red Cross or the blood center where you plan to donate.