Is Saw Palmetto Safe To Take With Benadryl?

In our latest question and answer, the pharmacist discusses whether or not saw palmetto can safely be taken with Benadryl (diphenhydramine).

Is Saw Palmetto Safe To Take With Benadryl?
May 30, 2018

Nick asked

I take saw palmetto for my prostate and want to know if it is okay to take with Benadryl.


Saw PalmettoSaw Palmetto and Benadryl do not interact and are considered safe to take together. However, if you are using saw palmetto to treat an enlarged prostate, its most common use, it is important to know that Benadryl can worsen the symptoms of conditions that obstruct urine flow, like BPH (benign prostatic hypertrophy). If you have an enlarged prostate, it would be prudent to discuss the use of Benadryl with your doctor before use.

What Is Saw Palmetto?

Saw palmetto, also known as the American Dwarf palm tree, has been historically used to treat several conditions, including:

  • Prostatitis
  • Chronic pelvic pain syndrome
  • Benign Prostatic Hypertophy (BPH)
  • Sexual dysfunction related to BPH

It is also, although less commonly, used as a mild diuretic and a sedative.

Several studies have found saw palmetto to be as effective in treating symptoms of mild to moderate BPH when compared to the commonly used prescription drug Proscar (finasteride), and tends to be well tolerated.

Saw palmetto does not have many major drug interactions but does seemingly have anti-estrogen effects, and therefore can interact with oral contraceptives if used in women. In addition, it may prolong bleeding time and needs to be used cautiously in those taking blood thinners.

One of the more common side effects seen with saw palmetto is orthostatic hypotension, which usually results in dizziness. Since Benadryl is a drug which can cause sedation, be aware that the combination of both may cause additive sedation/dizziness.

Taking Benadryl If You Have BPH

While not a contraindication, Benadryl needs to be used cautiously in those with an enlarged prostate or other conditions which cause urinary retention or bladder obstruction.

Benadryl, a sedating first-generation antihistamine, has strong anticholinergic effects, one of which is a "drying" effect one the body. This can cause symptoms of dry mouth, constipation and urinary retention and therefore could exacerbate existing conditions that cause difficult urination, such as an enlarged prostate.

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