Question

Medicated enemas may be given for the local effect they exert on the rectal mucosa. A common example is one containing the antibiotic neomycin, which is used to reduce bacteria in the colon before bowel surgery. Medicated enemas can also be given to produce a systemic effect.

Answer 1

Antibiotics can disrupt gut bacteria balance leading to C. difficile infections, which may be treated by a fecal transplant. Medicated enemas like neomycin reduce bacteria locally in the colon, while some drugs are formulated for enteric administration to avoid degradation by stomach acid.

Step-by-step explanation:

Antibiotics can lead to C. difficile infections by disrupting the normal balance of bacteria in the colon. This occurs because high doses of antibiotics can eliminate many of the harmless or beneficial gut bacteria, paving the way for the overgrowth of C. difficile. This bacterium is naturally resistant to many antibiotics and can cause severe gastric problems, including chronic diarrhea. To treat this, a fecal transplant from a healthy donor to the affected patient can be used to restore the gut's microbiota, which has shown over a 90% success rate in resolving C. difficile infections.

The use of medicated enemas, such as those with neomycin, aims at reducing bacteria in the colon to prepare for bowel surgery, thereby exerting a local effect on the rectal mucosa. However, there are cases when drugs are not well absorbed from the gastrointestinal tract, leading to medications such as niclosamide for intestinal tapeworms, or topical preparations like bacitracin for skin infections. In conditions where oral drug administration is not viable, alternative routes such as enteric administration ensure that nutrients or medications reach the intended site without being degraded by stomach acids.