Josamycin and Cyclosporine Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Cyclosporine Injection
Josamycin
No brand names on record
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
Concomitant administration of cycloSPORINE and josamycin (2 to 3 g daily) has been reported to result in significant increases in cycloSPORINE plasma levels and enhancement of cycloSPORINE induced nephrotoxicity143. This interaction has been confirmed on rechallenge 4.
Why it happens (mechanism)
Inhibition of hepatic metabolism
Literature reports
5 reports — tap to read
a) Josamycin may inhibit cytochrome P-450 activity in some patients, particularly with the use of higher doses (3 g daily) 1. Until further data is available, close monitoring of cycloSPORINE serum levels is indicated during combined therapy with josamycin.
b) Five cases in which josamycin interacted with cycloSPORINE in renal transplant patients were reported 2. The patients ranged in age from 35 years to 66 years, and all had increases in cycloSPORINE levels which required dosing reductions after josamycin 1 gram every 12 hours was added to therapy.
c) Three case reports suggested a pharmacokinetic interaction between josamycin and cycloSPORINE in cardiac transplant patients 3. Patient 1, a 55-year old man, had cycloSPORINE concentrations in the range of 154 ng/mL to 249 ng/mL while taking cycloSPORINE 7 mg/kg per day for 10 days. Nineteen days later, the patients was given oral josamycin 1 g three times daily for pneumonia. Over the next few days, cycloSPORINE levels began to increase, reaching toxic levels of 811 ng/mL. The patient developed increased serum creatinine, increased serum bilirubin, and jaundice. The cycloSPORINE dose was reduced to 6.18 mg/kg per day. After discontinuation of josamycin on the fifth day of treatment, cycloSPORINE reached therapeutic levels five days later.
d) Patient 2, a 23-year old man, had concentrations of cycloSPORINE that increased to 658 ng/mL from 277 ng/mL at a dosage of 5.3 mg/kg per day after oral josamycin 1 g three times daily was given to treat an infection. After josamycin was discontinued, cycloSPORINE returned to the therapeutic range 3.
e) Patient 3, a 42-year old man, had cycloSPORINE concentrations between 320 ng/mL and 360 ng/mL at a dosage of 8 mg/kg per day. After being given oral josamycin 1 gm three times daily and 960 mg cotrimoxazole twice daily, the patient developed toxic cycloSPORINE concentrations of 1154 ng/mL, renal impairment, elevated bilirubin, and conjunctival jaundice. Serum cycloSPORINE concentrations returned to therapeutic levels six days after josamycin was reduced to 1 g twice daily and cycloSPORINE was decreased to 1.7 mg/kg per day 3.
Common questions
Can I take Josamycin 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 Josamycin and Cyclosporine Injection interaction?
It is rated moderate. Can be significant — usually manageable with 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 Josamycin 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 anything you'd monitor while I'm on both?
References (4)
- Azanza J, Catalan M, Alvarez P, et al: Possible interaction between cyclosporine and josamycin (letter). J Heart Trans 1990; 9:265.
- Torregrosa JV, Campistol JM, Franco A, et al: Interaction of josamycin with cyclosporin A. Nephron 1993; 65:476-477. PubMed
- Azanza JR, Catalan M, Alvarez MP, et al: Possible interaction between cyclosporine and josamycin: a description of three cases. Clin Pharmacol Ther 1992; 51:572-575. PubMed
- Kreft-Jais C, Billaud EM, Gaudry C, et al: Effect of josamycin on plasma cyclosporine levels. Eur J Clin Pharmacol 1987; 32:327-328. PubMed
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