Cimetidine and Cyclosporine Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cimetidine
Cyclosporine Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of cycloSPORINE toxicity (renal dysfunction, cholestasis, paresthesias)
Interaction Deep Dive
Use caution when using cycloSPORINE with other drugs which are known to impair renal function like cimetidine. During the concomitant use of a drug that may exhibit additive or synergistic renal impairment with cycloSPORINE, close monitoring of renal function (serum creatinine) should be performed. Also, coadministration of cycloSPORINE (a CYP3A4 and P-gp substrate) with cimetidine ( a CYP3A4 and P-gp inhibitor) may increase cycloSPORINE exposure. If a significant impairment of renal function occurs, reduce the dosage of the cycloSPORINE and/or coadministered drug or consider an alternative treatment12. Cimetidine significantly raises cycloSPORINE concentrations in transplant recipients 5. Concurrent use of cycloSPORINE and H2-receptor antagonists results in increased serum creatinine compared to cycloSPORINE use alone 4.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of cycloSPORINE; inhibition of P-gp-mediated efflux transport of cycloSPORINE; competition between cimetidine and creatinine for renal tubular secretion
Literature reports
2 reports — tap to read
a) In a study, the effect of cimetidine was found to be more pronounced than raNITIdine on creatinine clearance, when given with cycloSPORINE. It was shown that there was no significant difference in the clearance of inulin, indicating that the change in creatinine clearance was due to competition with cimetidine for tubular secretion; not due to a decrease in glomerular filtration or nephrotoxicity 3.
b) In a case report, elevated cycloSPORINE levels and serum creatinine were associated with the concomitant administration of metronidazole and cimetidine. No significant degree of renal dysfunction developed in this case; however, metronidazole and cimetidine should be used cautiously in cycloSPORINE-treated patients 5.
Common questions
Can I take Cimetidine and Cyclosporine Injection together?
An increased risk of cycloSPORINE toxicity (renal dysfunction, cholestasis, paresthesias) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cimetidine and Cyclosporine Injection interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Cimetidine or Cyclosporine Injection need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (5)
- Product Information: NEORAL(R) oral soft gelatin capsules oral solution, cyclosporine modified oral soft gelatin capsules oral solution. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2023. DailyMed
- Product Information: SANDIMMUNE(R) oral capsules, oral solution, intravenous injection, cyclosporine oral capsules, oral solution, intravenous injection. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2023. DailyMed
- Pachon J, Lorber MI, & Bia MJ: Effects of H2-receptor antagonists on renal function in cyclosporine treated renal transplant patients. Transplantation 1989; 47:254-259. PubMed
- Jarowenko MV, Van Buren CT, Kramer WG, et al: Ranitidine, cimetidine and the cyclosporine-treated recipient. Transplantation 1986; 42:311-312. DOI
- Zylber-Katz E, Rubinger D, & Berlatzky Y: Cyclosporine interactions with metronidazole and cimetidine (letter). Drug Intell Clin Pharm 1988; 22:504-505. PubMed
Keep reading about Cimetidine
Keep reading about Cyclosporine Injection
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