Diphenhydramine
Diphenhydramine (DPH) is an antihistamine medication. It is mainly used to treat allergies. It can also be used to treat insomnia, the common cold, tremor in parkinsonism, and nausea. It is taken by mouth, injected into a vein, injected into a muscle, or put on the skin. It works best two hours after taking, and works for up to seven hours.