Why does Benadryl make my heart race?

Some second-generation antihistamines, notably terfenadine and astemizole, have been associated with prolongation of the QT interval and the development of torsades de pointes, a potentially fatal ventricular arrhythmia .

A decongestant eases congestion by constricting the blood vessels in your nasal passages. This dries up nasal mucus. But these medications can also abnormally stimulate the heart and blood vessels throughout the body . “This can cause an increase in blood pressure and heart rate, or skipped beats.

In the drug realm, antihistamines such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), cetirizine (Zyrtec), and loratadine (Claritin) can help with a stuffy nose are safe for the heart . Nasal sprays deliver a decongestant right where you need it.

Cold and Allergy Medications Can Trigger Afib For most people, nonprescription medications for stuffy and runny noses are fine, but cold/allergy medicine and atrial fibrillation don’t mix well. Use caution when taking these remedies because they could cause more frequent episodes of an irregular heartbeat.