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Diphenhydramine Injection

Products Affected - Description

    • Diphenhydramine injection, Pfizer, 50 mg/mL, 1 mL Carpuject syringe, 10 count, NDC 00409-2290-31

Reason for the Shortage

    • Fresenius Kabi has diphenhydramine injection available.[1]
    • Hikma did not provide a reason for the shortage.[2]
    • Mylan refuses to provide availability information.[3]
    • Pfizer has dipehnhydramine injection on shortage due to manufacturing delays.[4]

Available Products

    • Diphenhydramine injection, Fresenius Kabi, 50 mg/mL, 1 mL Simplist syringe, 10 count, NDC 76045-0102-10
    • Diphenhydramine injection, Fresenius Kabi, 50 mg/mL, 1 mL vial, 25 count, NDC 63323-0664-01
    • Diphenhydramine injection, Hikma, 50 mg/mL, 1 mL vial, 25 count, NDC 00641-0376-25

Estimated Resupply Dates

    • Pfizer has diphenhydramine 50 mg/mL 1 mL vials on back order and the company estimates a release date of August 2020.[4]

Alternative Agents & Management

    • Use oral diphenhydramine tablets and liquid where possible.
    • Ensure any intravenous diphenhydramine use is appropriate.
    • Review premedication protocols and remove injectable diphenhydramine whenever feasible. For example, diphenhydramine is not effective for preventing non-hemolytic transfusion reactions.[5]
    • Oral antihistamines including non-sedating options may be of use in allergic pruritus and urticaria.
    • Hydroxyzine is another H1 receptor antagonist available for intramuscular injection.
    • Benztropine injection is an option for patients with acute dystonic reactions.
    • Low dose nalbuphine or naloxone injection is an option for patients with opioid-induced pruritus.[6-8]


    1. Fresenius Kabi (personal communications). August 17 and 29, September 6, 14, 21, and 28, October 5, 12, 20, and 26, November 2, 16, 23, and 29, December 9, 14, and 27, 2018; January 18, February 1, March 1, 15, 21, and 29, April 19 and 26, May 24, June 27, and July 18, 2019.
    2. Hikma (personal communications). August 15 and 29, September 5, 19, and 26, October 3, 17, 24, and 31, November 7, 14, 21, and 28, December 5, 12, and 20, 2018; January 23 and 30, February 27, March 13 and 20, April 17 and 24, May 22, June 27, and July 17, 2019.
    3. Mylan Institutional (personal communications). August 15, September 19, October 22, November 2 and 8, 2018; January 22, February 19, March 29, April 22 and 30, May 23, and June 27, 2019.
    4. Pfizer (personal communications). August 17 and 29, September 7 and 17, October 5, 17, and 25, November 8, 23, and 30, December 7, 2018; January 22, March 1 and 14, and April 1, 19, and 30, May 24, and July 19, 2019.
    5. Mart­-Carvajal AJ, Sol I, Gonz¡lez LE, Leon de Gonzalez G, Rodriguez-Malagon N. Pharmacological interventions for the prevention of allergic and febrile non-haemolytic transfusion reactions. Cochrane Database Syst Rev. 2010 Jun 16;(6):CD007539. doi: 10.1002/14651858.CD007539.pub2. Review. PubMed PMID: 20556779
    6. Tubog TD, Harenberg JL, Buszta K, Hestand JD. Prophylactic Nalbuphine to Prevent Neuraxial Opioid-Induced Pruritus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Perianesth Nurs. 2018 Oct 30. pii: S1089-9472(18)30278-8. doi: 10.1016/j.jopan.2018.06.098. [Epub ahead of print] PubMed PMID: 30389225.
    7. He F, Jiang Y, Li L. The effect of naloxone treatment on opioid-induced side effects: A meta-analysis of randomized and controlled trails. Medicine (Baltimore). 2016 Sep;95(37):e4729. doi: 10.1097/MD.0000000000004729. Review. PubMed PMID: 27631221; PubMed Central PMCID: PMC5402564.
    8. Liao CC, Chang CS, Tseng CH, Sheen MJ, Tsai SC, Chang YL, Wong SY. Efficacy of intramuscular nalbuphine versus diphenhydramine for the prevention of epidural morphine-induced pruritus after cesarean delivery. Chang Gung Med J. 2011 Mar-Apr;34(2):172-8. PubMed PMID: 21539759.


Updated July 22, 2019 by Michelle Wheeler, PharmD, Drug Information Specialist. Created August 21, 2018 by Michelle Wheeler, PharmD, Drug Information Specialist. © 2019, Drug Information Service, University of Utah, Salt Lake City, UT.


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