Hi,
I do not know about your question regarding "iron".
However, Tylenol, can effect your INR if you take too much of it. It will raise your INR level.
This information s from Medline.
http://www.nlm.nih.gov/medlineplus/druginfo/medmaster/a681004.html
Before taking Acetaminophen (Tylenol)
tell your doctor and pharmacist if you are allergic to acetaminophen, any other medications, or any of the ingredients in the product. Ask your pharmacist or check the label on the package for a list of ingredients.
do not take two or more products that contain acetaminophen at the same time. Many prescription and nonprescription medications contain acetaminophen in combination with other medications. Read the package labels or ask your doctor or pharmacist to be sure that you do not take more than one product that contains acetaminophen at a time.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, or herbal products you are taking or plan to take. Be sure to mention anticoagulants ('blood thinners') such as warfarin (Coumadin); isoniazid (INH); certain medications for seizures including carbamazepine (Tegretol), phenobarbital, and phenytoin (Dilantin); medications for pain, fever, coughs, and colds; and phenothiazines (medications for mental illness and nausea). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have any serious medical condition.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking acetaminophen, call your doctor.
if you drink three or more alcoholic beverages every day, ask your doctor if you should take acetaminophen. Ask your doctor or pharmacist about the safe use of alcoholic beverages while taking acetaminophen.
you should know that combination acetaminophen products for cough and colds that contain nasal decongestants, antihistamines, cough suppressants, and expectorants should not be used in children less than 2 years of age without first talking to your child's doctor and following his or her instructions carefully. Improper use of these medications in young children can caused serious and life-threatening effects or death.
if you have phenylketonuria (PKU, a inherited condition in which a special diet must be followed to prevent mental retardation), you should know that some brands of acetaminophen chewable tablets may be sweetened with aspartame that forms phenylalanine
If someone takes more than the recommended dose of acetaminophen, get medical help immediately, even if the person does not have any symptoms. Symptoms of overdose may include:
nausea
vomiting
loss of appetite
sweating
extreme tiredness
unusual bleeding or bruising
pain in the upper right part of the stomach
yellowing of the skin or eyes
flu-like symptoms