Diphenhydramine (DPH) is an over-the-counter antihistamine used to relieve symptoms of allergies and the common cold or occasional sleeplessness. Benadryl is the most common brand name for DPH, and some other medications that may contain DPH include Advil, Motrin, Sudafed and Unisom. DPH can come in tablet form, a capsule or a liquid.[1]
When taken in quantities greater than the recommended dose or combined with other substances, DPH can result in elevated mood, increased energy levels and mild euphoria, or induce hallucinations.[2]
Slang terms for DPH or its misuse include drill, benadryled, diph, pink dreamz and benny tripping.
In 2020, the Food and Drug Administration (FDA) issued a warning that taking more diphenhydramine than recommended can lead to serious health effects, including heart problems, seizures, coma or even death. This was made in response to a “Benadryl challenge” circulating online among teenagers that was reportedly associated with illness and at least one death.[4]
Side effects of DPH include drowsiness, dizziness, nausea, headache, muscle weakness, nervousness, dry mouth and constipation.[5] DPH often is present in combination products containing ingredients like dextromethorphan (DXM) that are misused by youth, which can exacerbate the dangerous effects if taken beyond recommended doses.
While DPH misuse can be difficult to identify, and antihistamine overdose is not typically fatal, some symptoms of DPH overdose include:[6]
To help prevent misuse, keep DPH and all medications out of sight and out of reach of children and adolescents and dispose of all expired and unwanted medications safely.