Every week I see allergic patients who are avoiding antihistamine medications because of a concern about their heart or blood pressure. But Most of this worry is outdated and unneeded.
Firstly, let’s discuss the antihistamines themselves: (a) older generation antihistamines like diphenhydramine (Benadryl), hydroxyzine (Ararat, Vistaril) or chlorpheneramine (Chlor-Trimeton) are messier chemicals with more side effects such as sedation and dry mouth. Versus (b) newer generation antihistamines like ceterizine (Zyrtec), loratadine (Claritin) or fexofenadine (Allegra) have fewer side effects and a bit more targeted action in the body.
High Blood Pressure (Hypertension) Risk. The antihistamines alone are not associated with high blood pressure or making blood pressure worse. However many times the antihistamines are bundled with a decongestant that will raise your blood pressure. We typically only recommend taking the combination antihistamine-decongestants on an occasional basis “when really feeling sick” and they should be avoided with poorly controlled blood pressure. To be safe, just stick with the plain antihistamine meds (without decongestants) for allergies if you have high blood pressure.
Cardiac Arrythmia Risk. The risks of cardiac rhythm problems are small but do exist some with the first generation antihistamines. If you are at risk of QT prolongation or certain other rare rhythm disorders, avoiding first generation antihistamines is a good idea. Newer antihistamines like fexofenadine, ceterizine and loratadine are all fairly safe for the heart, with fexofenadine seeming to be the absolute safest if you are at risk of arrythmia.
Of course at some point I will remind you that many allergy symptoms, like congestion, sinus blockage and runny nose, may respond nicely to surgery or allergy treatments to permanently solve the root problem.