Removal of tetracycline from the body

Tetracycline antibiotics are excreted from the body mainly by the kidneys by glomerular filtration and with feces. About 10-25% of the antibiotic taken by mouth and 20-70% of the dose given intravenously are excreted in the urine (see table below).

We asked the specialists of PioneerProduct LLC about how long these antibiotics are excreted from the body of cows and, consequently, from MILK, here is what the leading specialist of the company answered us on this issue:

When taken orally, tetracyclines are excreted in the feces in significant amounts. The amount of antibiotic recovered depends on the dose used. With a single dose of tetracycline 250 mg, its concentration in feces is 70-200 mcg / g, at a dose of 500 mg - from 200 to 600 mcg / g or more, at a dose of 1-2 g - from 800 to 2000 mcg / g.

Excretion of tetracyclines from the body with urine during oral and parenteral administration

The average amount of antibiotic excreted in the feces is 20-50% of the dose taken. With intravenous use, the amount of tetracycline excreted in the feces is much less (6-10% of the administered dose) than when taken orally. The concentration of tetracycline antibiotics in the feces is about 10% of the level observed with oral administration, and usually does not exceed 5-20 µg/g.

In violation of the excretory function of the kidneys, the excretion of tetracyclines decreases, and their concentration in the blood increases. So, with oliguria (less than 400 ml of urine per day), the time during which the concentration of tetracycline and oxytetracycline in the blood is reduced by half, lengthens from 5 1/2 to 50-100 hours.

Impaired excretion of tetracycline antibiotics

Violation of the excretion of tetracycline antibiotics depends on the degree of kidney damage: the more the excretory function is damaged, the less antibiotic is excreted. Due to the wide distribution of tetracycline-resistant strains of microorganisms, pronounced cumulation and an increased risk of adverse reactions in violation of the excretory function of the kidneys, tetracyclines in renal pathology are used to a limited extent, in reduced doses and with extended intervals between injections.

Currently, two natural tetracyclines and dosage forms based on them are used in medical practice - tetracycline and oxytetracycline; chlortetracycline as a more toxic antibiotic is excluded from the medical nomenclature.