Drug Interaction Report

Chloramphenicol Injection and Chlorpropamide: Interaction Details

A pharmacist-reviewed analysis of the Chloramphenicol Injection and Chlorpropamide interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Chloramphenicol Injection

Chloromycetin® Injection Mychel-S® Injection Viceton
+

Chlorpropamide

Diabinese® Glucamide®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
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.

Of 30 documented Chloramphenicol Injection interactions, 17 are rated moderate — including this one.
Onset
delayed
Evidence
probable
Severity
Moderate

What happens

Hypoglycemia (CNS depression, seizures)

Interaction Deep Dive

Doses of 2 grams chloramphenicol per day will increase chlorproPAMIDE levels. The half-life has been reported to increase from 40 to 146 hours31.

Why it happens (mechanism)

May increase chlorproPAMIDE half-life

Literature reports

1 report — tap to read

a) Chloramphenicol has previously been shown to prolong the half-life of tolbutamide presumably by impairing its metabolism by the liver 1. Preliminary results from other researchers indicate that the half-life of chlorproPAMIDE may also be prolonged by concomitant chloramphenicol administration. In five subjects receiving chloramphenicol (1.5 to 3.0 g daily), the half-lives of chlorproPAMIDE were 40, 60, 82, 116 and 146 hours. The half-life of chlorproPAMIDE is normally in the range of 30 to 36 hours. The mechanism of this interaction has not been established but may be due to inhibition of chlorproPAMIDE metabolism 2.

Common questions

Can I take Chloramphenicol Injection and Chlorpropamide together?

Hypoglycemia (CNS depression, seizures) Always confirm with your pharmacist or prescriber before making any change.

How serious is the Chloramphenicol Injection and Chlorpropamide 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 Chloramphenicol Injection or Chlorpropamide 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 (3)

  1. Christensen LK & Skovsted L: Inhibition of drug metabolism by chloramphenicol. Lancet 1969; 2:1397. DOI
  2. Petitpierre B & Fabre J: Chlorpropamide and chloramphenicol. Lancet 1970; 1:789. PubMed
  3. Petitpierre B, Perrin L, Rudhardt M, et al: Behavior of chlorpropamide in renal insufficiency and under the effect of associated drug therapy. Int J Clin Pharmacol Ther Toxicol 1972; 6:120-124.
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Chloramphenicol Injection

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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.