Hi & Welcome to HCM.
I appreciate your concern for the safety of Benadryl for sneezing and running nose in presence of
rapid heart rate.
Benadryl (
Diphenhydramine) is a sedating antihistamine used for the symptomatic treatment of
common cold symptoms like running nose, nasal block, watery eyes.
It is known to cause
drowsiness, an increased heart beat,
constipation, dry mouth, blurring of vision, etc.
Since its use is associated with increased heart beat, hence it should not be used to treat running nose or watery eyes in presence of rapid heart beat due to the use of Albuterol inhaler.
Steam inhalation or the nasal decongestant are the best alternative.
A non sedating anti histamine which is less likely to cause increase heart beat like Levocetrizine can be another right choice.
Hope I could answer your query.
A feed back is appreciated.