Panadol night tablets contain two active ingredients, paracetamol and diphenhydramine. Despite paracetamols widespread use for over 100 years, scientists still don't fully understand its bio-mechanisms. The main belief is that it reduces the production of prostaglandins in the brain and spinal cord. Diphenhydramine is a sedating H1 antagonist. Diphenhydramine works by blocking the effects of histamine and causes drowsiness. The combination of the active ingredients in Panadol night can be used to relieve mild to moderate pain such as headaches, backache or period pain that is causing difficulty getting to sleep.