Question

Why we can't take antiseptic drugs such as chlorhexidine or iodine internally, while antibiotics such as penicillin can be taken internally?

Answer 1

Before we answer to this question why we can't take antiseptic drugs such as Chlorhexidine or Iodine internally, while antibiotics such as penicillin can be taken internally.

Antiseptic: Antiseptics may be defined as antimicrobial substances that are non damaging to living tissues or skin while reducing the possibilities of infection, sepsis, putrefaction. Example: hydrogen peroxide, rubbing alcohol, chlorhexidine and iodine.

Antibiotics: Antibiotics may be defined as a drug used to treat bacterial infections. Originally, an antibiotic was a substance produced by one microorganism that selectively inhibits the growth of another. Example: Penicillin, cephalosporin, Erythromycin, etc.

There are several reason why antiseptic are not used internally unlike antibiotics which can be used orally.

1. Pharmacokinetic properties:

• Absorption: Due to the large molecular size the antiseptics can not get absorbed through the lumen of internal blood vessels where as antibiotics can get absorbed.

• Distribution: Due to the unbalanced lipophilicity and hydrophilicity (HLB) the antiseptics undergo over protein binding or no protein binding.

• Metabolism: Due to the altered chemical structures they are either over sensitive or sensitive resistance to the metabolic enzymes unlike antibiotics

• Elimination: Unlike antibiotics antiseptics are not get eliminated easily from the body fluids.

2. Pharmacodynamic:

• Toxicity: Toxicity will be more if the drug remain for he longer time.
• Antiseptics are more toxic than antibiotics.
• Pleutropism / Pleutropic Phenomena: Antiseptic do not exactly bound to the 3D stucture of the receptors and also show its activity to the different different site. For example: Iodine given orally can interfere with the natural absorption of Iodine and may leads to thyroid related complications.
• Antiseptics generally shows the local action however antibiotics like penicillin shows systemic actions as well.

3. Others: Due to so many other incompatibilities issues like:

A. Physical incompatibility

B. Chemical incompatibility and

C. Therapeutic incompatibility

Prolonged retention in the GIT tract may cause severe allergy and irritation in the GIT.

Antiseptics are not used internally however the antibiotics are used orally.

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