DIY Injectable Benadryl as a Local Anesthetic Option

Disclaimer.  I am not a licensed health practitioner.  This is just another post on an item you might wish to have available if needed so that a physician can treat you and your family as best as possible.  No medication, including those available over the counter, should be taken without consulting a physician.  Information shared here is for educational and entertainment purposes only.  It is not medical advice nor a substitute for licensed medical care.  A qualified, licensed physician or other medical provider should be consulted before beginning any herbal or conventional treatment.

Previous blogposts on Benadryl (diphenhydramine hydrochloride) addressed this wonder drug’s numerous applications in austere medical situations and have alluded to its possible use as an injectable local anesthetic.  And while this is something that untrained people should leave to licensed medical personnel, it’s very important to understand how this form of Benadryl is made and how it can be used in an emergency when other options are lacking.

Lidocaine is generally the preferred option for local injectable anesthetics.  The lidocaine powder and production of an injectable form has previously been discussed.  While the injectable solution is a prescription-only item, the powder itself is not and is relatively inexpensive.

The injectable Benadryl solution has been in limited use since 1939 for minor surgery involving the skin, feet, and dental procedures, particularly in individuals allergic to lidocaine or other –caine family anesthetics.[1]  A 0.5% solution of diphenhydramine was shown to be as effective as a 1% solution of lidocaine as a local anesthetic for minor wound repair.[2]  However, diphenhydramine does not anesthetize as well as lidocaine for facial wounds, and it does cause more injection site-related pain than lidocaine.[3]  Nevertheless, it is an effective alternative local anesthetic for oral surgery in –caine allergic patients.[4]

Injectable Benadryl is an alternative for those late to the show, uncomfortable with the idea of ordering lidocaine, or allergic to lidocaine.  It offers another option for minimizing the pain involved with suturing wounds closed.  This information is not widely available; even Dr. Joseph Alton, doctor and author of The Survival Medicine Handbook, was unaware of the potential for using Benadryl as an injectable local anesthetic.  Unfortunately, it is a prescription-only item.  And it’s not even available through All Day Chemist.  If you can get your doctor to prescribe it for you, you’re golden. 

If not, what are your options?  Can Benadryl capsules be used to make an injectable solution?  Here’s where you’ll want to get your doctor involved.  The issue lies not just with the ability to make a sterile solution, but also with the diphenhydramine powder from the capsule.  Unfortunately, the powder in the capsules isn’t pure diphenhydramine.  Though it has far fewer fillers and additives than the tablets, it still has some additives like sodium lauryl sulfate and magnesium stearate.  They are commonly used in pharmaceutical production of capsules.  But they aren’t substances to be injected, unfortunately.  You simply must obtain the actual diphenhydramine vials.  Once you’ve got that covered, the rest is easy.  Here are the steps:

Draw up entire contents of vial containing 50 mg/mL diphenhydramine into the syringe. This should measure to a volume of 1 mL.

Dilute the contents of the syringe with 4 mL of 0.9% sodium chloride to yield a final volume of 5 mL. (Discard the remaining sodium chloride solution.)

Clearly label the contents of the syringe with the medication label as “Diphenhydramine 1% (10 mg/mL).[5] 

While clinical trials have been conducted using a diphenhydramine solution of up to 2%, most studies note the best results using a 1% solution.

 

Contraindications:  Benadryl should not be used in patients with a history of previous reactions to Benadryl in any form, nor should it be used for anesthetizing fingers, toes, nose, ears, or genitalia.  Nor should it be used in pregnant or nursing women, or those with asthma, peptic ulcers, or obstructive bowel disease.[6]

Links to related posts:

Lidocaine--Why You Want It and Where to Get It

Benadryl Uses

Wound Closure Supply Options

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[1] Peter G. Pavlidakey, et al., “Diphenhydramine as an Alternative Local Anesthetic Agent,” The Journal of Clinical and Aesthetic Dermatology, October 2009, Vol 2 No 10, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923931/ (accessed 3 March 2021).

[2] A. A. Ernst, et al., “1% lidocaine versus 0.5% diphenhydramine for local anesthesia in minor laceration repair,” Annals of Emergency Medicine, June 1994, Vol 23 No 6, https://pubmed.ncbi.nlm.nih.gov/8198309/ (accessed 3 March 2021).

[3] Peter G. Pavlidakey, et al., “Diphenhydramine as an Alternative Local Anesthetic Agent,” The Journal of Clinical and Aesthetic Dermatology, October 2009, Vol 2 No 10, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923931/ (accessed 3 March 2021).

[4] W. J. Gallo, et al., “Efficacy of diphenhydramine hydrochloride for local anesthesia before oral surgery,” Journal of the American Dental Association, August 1987, Vol 115 No 2, https://pubmed.ncbi.nlm.nih.gov/3476650/ (accessed 3 March 2021).

[5] Craig Cocchio, “Preparation of diphenhydramine for injection for local anesthesia,” EmPharmD, 27 January 2016, https://empharmd.com/2016/01/27/trick-of-the-trade-diphenhydramine-for-local-anesthesia/ (accessed 3 March 2021).

[6] Peter G. Pavlidakey, et al., “Diphenhydramine as an Alternative Local Anesthetic Agent,” The Journal of Clinical and Aesthetic Dermatology, October 2009, Vol 2 No 10, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923931/ (accessed 3 March 2021).

 

 9 march 2021