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MSA Diphenhydramine-containing Medicines

SAHPRA alerts all healthcare professionals about the risk of serious heart problems, seizures, coma and death associated with the use of high doses of diphenhydramine- containing medicines.

The South African Health Products Regulatory Authority (SAHPRA) wishes to alert healthcare professionals about the risk of serious heart problems, seizures, coma and death associated with the use of high doses of diphenhydramine-containing medicines. An online challenge known as “the Benadryl Challenge” has recently been in the news. Benadryl® is not registered in South Africa (SA), but several products available in SA contain diphenhydramine and may be similarly misused (see SAHPRA website for a list of diphenhydramine-containing medicines).

“Benadryl Challenge” is a TikTok trend, which encourages social media users through an online video to overdose on over-the-counter (OTC) Benadryl® in order to hallucinate. At least one teenager has reportedly died due to complications resulting from attempting the “challenge” in August 2020. These incidents prompted the manufacturer of Benadryl® in the United States, in collaboration with the US regulator, TikTok and other social media platforms, to remove content that displays the “challenge”.

Diphenhydramine is mainly used to treat symptoms of allergic reactions (runny nose; sneezing; itchy, watery eyes; and itchy throat), insomnia, and motion sickness. Common side effects include drowsiness, dizziness, constipation, stomach upset, blurred vision, and dry mouth/nose/throat, and serious side effects include hallucination, psychosis, seizures, and coma.

Considering that there are multiple diphenhydramine-containing medicines registered in SA, SAHPRA urges healthcare professionals to be vigilant about potential misuse of diphenhydramine-containing medicines (including increased sales of OTC diphenhydramine-containing medicines) which may be motivated by the “challenge”. Healthcare professionals are advised to heed the following warnings regarding diphenhydramine- containing medicines:

  • Be aware that the “Benadryl Challenge” may be occurring among teens and alert their caregivers about it.
  • Encourage teens and caregivers to read the patient information leaflets included in the medicine package in order to familiarize themselves with the recommended doses and important safety information.
  • Advise consumers, parents and caregivers to store diphenhydramine-containing medicines and all other OTC and prescription medicines out of children’s reach and sight. It is recommended that medicines should be locked up to prevent accidental poisonings by children and misuse by teens, especially when they are home more often due to the COVID-19 pandemic and may be more likely to experiment.

Healthcare professionals are advised to report any adverse drug reactions, including product quality problems to SAHPRA via the eReporting link available on SAHPRA website (www.sahpra.org.za). Alternatively, please complete an ADR reporting form available on the SAHPRA website and email it to adr@sahpra.org.za. Healthcare professionals may also use the National Department of Health Mobile Application accessible from the Essential Medicines List (EML) Clinical Guide.


1. FDA warns about serious problems with high doses of the allergy medicine diphenhydramine (Benadryl®). (Accessed on 24 September 2020). https://www.fda.gov/drugs/drug-safety-and-availability/fda-warns- about-serious-problems-high-doses-allergy-medicine-diphenhydramine-benadryl

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