A million-dollar wound or Blighty wound is military slang referring to a type of wound received in combat which is serious enough to get the person sent away from the fighting, but is not fatal, nor will it leave the person permanently crippled.
In conclusion, Benadryl does not cause kidney damage directly, but if you uses excessively over a long period of time and there is urinary retention, the chronic urinary retention could ending producing kidney failure.
Common Side Effects of Benadryl. The most common Benadryl side effect is drowsiness. At least 1 percent of all patients taking Benadryl report some level of drowsiness. In most cases, this does not impact the patient's ability to function. It can, however, lead to a lack of focus or other issues that may have an effect on daily activities.