Levonorgestrel and Tysabri

• Generic Name: levonorgestrel
• Dosage Forms: n.a.
• Other Brand Names: EContra EZ, Fallback Solo, My Way, Next Choice, Opcicon One-Step, Plan B One-Step, React, Aftera, EContra One-Step, My Choice, My Way, New Day, Next Choice One Dose, Take Action, Kyleena, Liletta, Mirena, Skyla

Levonorgestrel is an emergency contraceptive that is used to prevent pregnancy after unprotected sex or after failure of another birth control method. It works by preventing a woman's egg from fully developing. It may also prevent the attachment of the woman's egg to the wall of the uterus (womb).

No contraceptive method is 100 percent effective. Birth control methods such as having surgery to become sterile or not having sex are more effective. Levonorgestrel should not be used as a regular method of birth control. Discuss your options for birth control with your doctor.

Plan B One-Step® is available as an over-the-counter medicine for any woman of childbearing potential.

• Generic Name: natalizumab
• Dosage Forms: injection
• Other Brand Names: Tysabri

Tysabri (natalizumab) is a monoclonal antibody that affects the actions of the body's immune system. Monoclonal antibodies are made to target and destroy only certain cells in the body. This may help to protect healthy cells from damage.

Tysabri is used to treat relapsing forms of multiple sclerosis.

Tysabri is also used to treat moderate to severe Crohn's disease in adults. It is usually given after other medicines have been tried without success.