Medrol is used to treat inflammatory and allergic disorders.
Phenergan is used to relieve allergies such as skin rashes, itching and symptoms of hayfever. It can also be used to treat sickness, vertigo (loss of balance or dizziness), travel sickness and problems affecting the ear. It is also occasionally used to treat insomnia (difficulty sleeping).
Periactin is used in the treatment of allergies and some other conditions.