Iron Shots For Anemia Can Regular Iron Deficiency Anemia Be Life-threatening?

Can regular Iron Deficiency Anemia be life-threatening? - iron shots for anemia

My sister has a bad case of anemia, iron injections need. Iron pills are not sufficient to increase the amount of iron and hemoglobin in the blood. That is how it is. I know Sickel Cell Aplastic and are potentially fatal. Iron deficiency causes fatigue, listlessness, pallor, shortness of breath, nausea and dizziness. I think it can cause heart failure or cardiac arrest if not treated. Do you know if this can be very dangerous?