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Promethazine

Phenergan is the single promethazine product on this shelf, a 25 mg sedating antihistamine tablet used to calm allergic reactions, ease motion sickness and settle nausea.

Phenergan

Allergic States, Motion Sickness

25mg

Promethazine tablets for allergies and motion sickness. It blocks histamine and dampens the brain's nausea signal.

From$0.67/ tabletView

Key points

  • Do not give promethazine to children under 2. The label carries a boxed warning because of the risk of fatal respiratory depression in that age group.
  • Severe tissue damage has been reported with injectable promethazine regardless of the route used, including gangrene, tissue necrosis and thrombophlebitis; some cases required surgery or amputation.
  • Drowsiness is a direct effect of promethazine’s action in the brain, which is why Phenergan appears under Sleep Management.

How does Promethazine work?

Promethazine blocks histamine, the chemical your body releases during an allergic reaction. By stopping histamine from binding to its receptors, it reduces the swelling, itching and sneezing behind Allergic States. It also acts on a separate signal in the brain that triggers nausea, which is why promethazine is used for Motion Sickness. You feel drowsy because promethazine works on the brain as well as the body.

Further reading