What is the correct IM/IV dosing for diphenhydramine?

Diphenhydramine, an antihistamine commonly used to relieve allergy symptoms, has specific dosing guidelines for IM or IV administration. The standard dose for adults is typically 25mg to 50mg, with 25mg being the recommended initial dose for many situations, including allergic reactions and as a nighttime sleep aid.

Choosing 25mg aligns with standard clinical practice and recommendations. This dose is effective for providing relief from symptoms without exceeding the typical threshold that might lead to increased side effects, such as sedation. Higher doses, like 50mg, may be appropriate in certain situations or for specific patient populations, but they are generally not the first-line choice, especially in emergency settings where minimizing side effects is often a priority.

In practice, it's important to consider the specific context and individual patient factors when administering doses, but for the purpose of this question, 25mg serves as a widely accepted standard starting point.