Mylan Inc. said Tuesday that its partner Pfizer Inc. will market the EpiPen allergic reaction syringe in Japan.

The companies did not disclose financial terms of their agreement, which gives Pfizer exclusive rights to market EpiPen in Japan.

EpiPen is a pre-filled syringe used to treat severe allergic reactions. Pfizer, New York, owns the product and Mylan, based in Canonsburg, Pa., markets it in the U.S.

Japanese regulators have already approved EpiPen.

Mylan shares were unchanged at $23.25 Tuesday and lost a penny to $23.24 in after-hours trading. Pfizer shares fell 52 cents to $23.74 and declined another penny to $23.73 after-hours.