Most adults should stay at 300 mg or less in 24 hours from all diphenhydramine products, unless a clinician sets a different plan.

A typical adult dose of diphenhydramine is 25–50 mg every 4–6 hours, staying within the product’s 24-hour label limit.

For most pregnant adults, diphenhydramine label dosing is 25–50 mg every 4–6 hours, capped at 300 mg per day.

For most adults, a single dose is 25–50 mg by mouth; follow the package limits, and get urgent help fast if you took more than directed.

Many vets use diphenhydramine at 1 mg per pound per dose, spaced 8–12 hours apart, after checking your dog’s meds and health history.

Plain diphenhydramine is often used at about 1 mg per pound per dose, given every 8–12 hours, after your veterinarian OKs it for your dog.

For a 70-lb dog, a common diphenhydramine dose is 70 mg per dose, given every 8–12 hours when your vet says it fits.

Typical diphenhydramine dosing is 2–4 mg/kg every 8–12 hours, and drowsiness can happen.

A 50-lb dog is commonly given 25–50 mg diphenhydramine per dose every 8–12 hours, but the right amount depends on your dog’s health and the product.

An 80-lb dog often lands around 75–80 mg of plain diphenhydramine per dose, every 8–12 hours, after your veterinarian okays it.