If you have a diagnosediron deficiency, your doctor may prescribe Feriva 21/7 to help replenish your iron stores. Feriva 21/7 is a non-prescription iron supplement containing several ingredients to help with iron absorption and support the regrowth of red blood cells. Iron is a vital component in red blood cells, which carry oxygen to different parts of the body. Oxygen is used for various metabolic processes and is necessary for life. Symptoms of iron deficiency anemia can include headaches, dizziness, weakness, fatigue, pale skin, irregular heartbeat, shortness of breath, and cold hands and feet.