This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
When these two medicines are taken together, cimetidine may cause your body to process the blood-thinner more slowly.
What might happen:
The effect of the blood-thinner may increase.You may experience an increased chance for bleeding including bleeding from your gums, nosebleeds, unusual bruising, or dark stools.
What you should do about this interaction:
Ask your healthcare professionals (e.g. doctor or pharmacist) about taking these medicines together. If your doctor prescribes these medicines together, you may need to have your bleeding times checked more often. If you have any signs of bleeding, such as bleeding from your gums, nosebleeds, unusual bruising, or dark stools, contact your doctor right away.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Silver BA, Bell WR. Cimetidine potentiation of the hypoprothrombinemic effect of warfarin. Ann Intern Med 1979 Mar;90(3):348-9.
2.Wallin BA, Jacknowitz A, Raich PC. Cimetidine and effect of warfarin. Ann Intern Med 1979 Jun;90(6):993.
3.Serlin MJ, Sibeon RG, Breckenridge AM. Lack of effect of ranitidine on warfarin action. Br J Clin Pharmacol 1981 Dec;12(6):791-4.
4.Kerley B, Ali M. Cimetidine potentiation of warfarin action. Can Med Assoc J 1982 Jan 15;126(2):116.
5.Desmond PV, Mashford ML, Harman PJ, Morphett BJ, Breen KJ, Wang YM. Decreased oral warfarin clearance after ranitidine and cimetidine. Clin Pharmacol Ther 1984 Mar;35(3):338-41.
6.Toon S, Hopkins KJ, Garstang FM, Rowland M. Comparative effects of ranitidine and cimetidine on the pharmacokinetics and pharmacodynamics of warfarin in man. Eur J Clin Pharmacol 1987;32(2):165-72.
7.Cournot A, Berlin I, Sallord JC, Singlas E. Lack of interaction between nizatidine and warfarin during chronic administration. J Clin Pharmacol 1988 Dec;28(12):1120-2.
8.Hussey EK, Dukes GE. Do all histamine2-antagonists cause a warfarin drug interaction?. DICP 1989 Sep;23(9):675-9.
9.Hunt BA, Sax MJ, Chretien SD, Gray DR, Frank WO, Lalonde RL. Stereoselective alterations in the pharmacokinetics of warfarin enantiomers with two cimetidine dose regimens. Pharmacotherapy 1989; 9(3):184.
10.Baciewicz AM, Morgan PJ. Ranitidine-warfarin interaction. Ann Intern Med 1990 Jan 1;112(1):76-7.