Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Polypeptides

By

Brian J. Werth

, PharmD, University of Washington School of Pharmacy

Last full review/revision Jul 2020| Content last modified Jul 2020
Click here for the Professional Version
Topic Resources
  • Bacitracin

  • Colistin

  • Polymyxin B

Most bacteria have an outer covering (cell wall) that protects them. Bacitracin works by preventing bacteria from forming this wall. Colistin and polymyxin B work by disrupting the cell membrane underlying this wall in some bacteria. As a result, the bacteria die.

Colistin and polymyxin B commonly cause kidney damage, so they are used only for serious infections in which bacteria are resistant to all other antibiotics and no safer alternatives are available. When colistin or polymyxin B is used, it is given by vein (intravenously). In some cases, colistin may be inhaled through a nebulizer.

Table
icon

Use of Polypeptides During Pregnancy and Breastfeeding

With bacitracin, the risk to the fetus during pregnancy and to the newborn during breastfeeding is thought to be slight because bacitracin is applied topically and little of the drug is absorbed Drug Absorption Drug absorption is the movement of a drug into the bloodstream after administration. (See also Introduction to Administration and Kinetics of Drugs.) Absorption affects bioavailability—how quickly... read more into the bloodstream. However, its safety has not been established. The same is true for polymyxin B and colistin when they are applied topically.

Polymyxin B and colistin should be taken by injection during pregnancy only when the benefits of treatment outweigh the risks. With polymyxin B, no harmful effects on the fetus have been observed in animal studies, but no well-designed studies have been done in pregnant women. With colistin, harmful effects on the fetus have been observed in animal studies. (See also Drug Use During Pregnancy Drug Use During Pregnancy More than 50% of pregnant women take prescription or nonprescription (over-the-counter) drugs or use social drugs (such as tobacco and alcohol) or illicit drugs at some time during pregnancy... read more .)

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read

Test your knowledge

Chickenpox
Chickenpox is a highly contagious viral infection that tends to be fairly mild in most cases. Which of the following groups has the lowest risk of complications from chickenpox?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP