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.
Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
When these two medicines are taken together, your body may not process your seizure medicine properly.
What might happen:
The blood level of your seizure medicine may rise and cause an increase in the beneficial and toxic effects.
What you should do about this interaction:
If you experience changes in vision, loss of coordination, or drowsiness, contact your doctor. You doctor may check your blood levels of seizure medicine more often. It may be necessary to change the dose of your seizure medicine or change your cimetidine to a different medicine.Your healthcare professionals (e.g. doctor or pharmacist) 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.Sambol NC, Upton RA, Chremos AN, Lin ET, Williams RL. A comparison of the influence of famotidine and cimetidine on phenytoin elimination and hepatic blood flow. Br J Clin Pharmacol 1989 Jan;27(1):83-7.
2.Levine M, Jones MW, Sheppard I. Differential effect of cimetidine on serum concentrations of carbamazepine and phenytoin. Neurology 1985 Apr; 35(4):562-5.
3.Phillips P, Hansky J. Phenytoin toxicity secondary to cimetidine administration. Med J Aust 1984 Oct 27;141(9):602.
4.Iteogu MO, Murphy JE, Shleifer N, Davis R. Effect of cimetidine on single-dose phenytoin kinetics. Clin Pharm 1983 Jul-Aug;2(4):302, 304.
5.Salem RB, Breland BD, Mishra SK, Jordan JE. Effect of cimetidine on phenytoin serum levels. Epilepsia 1983 Jun;24(3):284-8.
6.Bartle WR, Walker SE, Shapero T. Dose-dependent effect of cimetidine on phenytoin kinetics. Clin Pharmacol Ther 1983 May;33(5):649-55.
7.Algozzine GJ, Stewart RB, Springer PK. Decreased clearance of phenytoin with cimetidine. Ann Intern Med 1981 Aug;95(2):244-5.
8.Hetzel DJ, Bochner F, Hallpike JF, Shearman DJ, Hann CS. Cimetidine interaction with phenytoin. Br Med J (Clin Res Ed) 1981 May 9; 282(6275):1512.
9.Neuvonen PJ, Tokola RA, Kaste M. Cimetidine-phenytoin interaction: effect on serum phenytoin concentration and antipyrine test. Eur J Clin Pharmacol 1981;21(3):215-20.
10.Frigo GM, Lecchini S, Caravaggi M, Gatti G, Tonini M, D'Angelo L, Perucca E, Crema A. Reduction of phenytoin clearance caused by cimetidine. Eur J Clin Pharmacol 1983;25(1):135-7.
11.Griffin JW Jr, May JR, DiPiro JT. Drug interactions: theory versus practice. Am J Med 1984 Nov 19;77(5B):85-9.
12.Sazie E, Jaffe JP. Severe granulocytopenia with cimetidine and phenytoin. Ann Intern Med 1980 Jul;93(1):151-2.
13.Arbiser JL, Goldstein AM, Gordon D. Thrombocytopenia following administration of phenytoin, dexamethasone and cimetidine: a case report and a potential mechanism. J Intern Med 1993 Jul;234(1):91-4.
14.Yue CP, Mann KS, Chan KH. Severe thrombocytopenia due to combined cimetidine and phenytoin therapy. Neurosurgery 1987 Jun;20(6):963-5.
15.Wong YY, Lichtor T, Brown FD. Severe thrombocytopenia associated with phenytoin and cimetidine therapy. Surg Neurol 1985 Feb;23(2):169-72.
16.Tse CS, Akinwande KI, Biallowons K. Phenytoin concentration elevation subsequent to ranitidine administration. Ann Pharmacother 1993 Dec; 27(12):1448-51.
17.Tse CS, Iagmin P. Phenytoin and ranitidine interaction. Ann Intern Med 1994 May 15;120(10):892-3.
18.Bramhall D, Levine M. Possible interaction of ranitidine with phenytoin. Drug Intell Clin Pharm 1988 Dec;22(12):979-80.
19.Watts RW, Hetzel DJ, Bochner F, Hallpike JF, Hann CS, Shearman DJ. Lack of interaction between ranitidine and phenytoin. Br J Clin Pharmacol 1983 Apr;15(4):499-500.
20.Bachmann KA, Sullivan TJ, Jauregui L, Reese JH, Miller K, Levine L. Absence of an inhibitory effect of omeprazole and nizatidine on phenytoin disposition, a marker of CYP2C activity. Br J Clin Pharmacol 1993 Oct; 36(4):380-2.