Does Benadryl Raise Blood Pressure?

In our latest question and answer, the pharmacist discusses whether or not Benadryl (diphenhydramine) can raise your blood pressure.

Does Benadryl Raise Blood Pressure?
Jul 01, 2018

Bootsie asked

I have hypertension, diagnosed years ago. Is Benadryl safe to take? I don't want it to raise my blood pressure at all.

Answer

Checking BPBenadryl (diphenhydramine) will not increase your blood pressure and is generally considered safe to take who are diagnosed with hypertension (high blood pressure). However, there are some rare cardiac side effects of Benadryl, which are most often seen in cases of overdose.

Cardiac Side Effect Of Benadryl

Cardiovascular side effects are not likely to occur with routine use of Benadryl when taken at the usual indicated dosages. However, due to the strong anticholinergic side effects of the drug, adverse cardiovascular effects could happen in susceptible individuals in or cases where high doses are taken. These side effects could potentially include:

  • Tachycardia (increased heart rate)
  • Palpitations
  • Arrhythmias
  • Hypotension
  • Elevations in blood pressure have been reported to occur, but are generally not of clinical significance.

The prescribing information for the diphenhydramine (the active ingredient in Benadryl) solution for injection only lists hypotension (low blood pressure), and not hypertension as a side effect. As mentioned however, this is uncommon with usual doses.

Summary

  • Benadryl, at usual doses, is not likely to affect blood pressure.
  • Both hypotension (low blood pressure) and hypertension (high blood pressure) have been reported, but generally only in cases of overdose.
  • Benadryl is generally considered safe to use in those with controlled hypertension.

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