Hello When IRON infusion needed , it should be taken under strict medical supervision . Since you took few iron tablets ,so there is no chance of any reaction . Take 2 ml iron solution from an ampoule , now withdraw blood from a vein ,mix it with iron solution and see whether it is reacting or not ( but in your case we are sure that it will not react because ,you have already taken iron tablet. When such patient visit I first of all start intravenous normal saline ( until and unless not contraindicated ). Now in I/V drip introduce 10 ml iron solution and infuse it in 5-6 hours . Patient may feel chills and rigor or temperature on next day ,so tylenol orally . This is my way and different doctors use different method ,so consult your doctor and get his opinion.